Papers directly focused on urban ecology
A multi-scale analysis of factors affecting the occurrence of forest songbirds in an urban landscape
Do urban areas act as a refuge from nest predation for an urban "winner", the Northern Mockingbird (Mimus polyglottos)?
Migratory stopover duration and movement of Swainson's Thrushes in an urban landscape
Effects of land-use intensity and forest patch complexity on avian diversity in an urbanized tropical island landscape [Puerto Rico]
Effect of landscape structure on bird communities in two subtropical forests of northern Taiwan
Reproductive timing of resident and migrant songbirds across an urban to rural gradient in central Ohio,USA
Papers not directly focused on urban ecology, but with urban ecology applications or aspects
The response of migrant landbirds to Tamarix invasion in riparian areas is influenced by floristics and physiognomy
Roadway mortality of raptors in southern Idaho
Papers directly focused on urban ecology
INTRODUCTION AND OVERVIEW: PAST KNOWLEDGE AND EXAMPLES OF NEW URBAN BIRD RESEARCH
Lepczyk, C. A., University of Wisconsin-Madison, Madison, United States, email@example.com; Warren, P. S. University of Massachusetts-Amherst, Amherst, United States, firstname.lastname@example.org; Machabee, L., Arizona State University, Tempe, United States, email@example.com; Pidgeon, A. M., University of Wisconsin-Madison, Madison, United States, firstname.lastname@example.org; Kinzig, A., Arizona State University, Tempe, United States, Ann.Kinzig@asu.edu; Flather, C.H., USDA, Forest Service, Fort Collins, United States, email@example.comRadeloff, V, C, University of Wisconsin-Madison, Madison, United States, firstname.lastname@example.org; Hammer, R. B., University of Wisconsin-Madison, Madison, United States, email@example.com
During the past decade, the study of birds in urban systems has come to the forefront of ornithology. This increase has been spurred by the continuing growth of urban areas, designation of two urban LTER sites, and publication of Avian Ecology and Conservation in an Urbanizing World in 2001. Five years since publication of this book, major advances have been made in several key areas of urban bird ecology that will be the focus of this symposium. In our introduction to the symposium, we will highlight one area of growth: the integration of social and biophysical science approaches to studying how urbanization influences birds. We will present and compare results of two current projects: 1) a comparison of how people influence birds on their property using social surveys from Phoenix, AZ and Southeast, MI (USA), and 2) how housing and population growth influence bird communities across ecoregions of the US. Survey results demonstrate that people actively engage in actions that influence birds, but exhibit differences across urbanization gradients and regions. Similarly, the national analysis indicates that housing and population have differential influences on bird communities across ecoregions. Both projects demonstrate the importance of integrative approaches for understanding birds in urban areas and touch upon key issues to be discussed by the symposium participants. http://silvis.forest.wisc.edu/people/lepczyk.asp
CITYWIDE MONITORING FOR BIRD SCIENCE AND CONSERVATION IN URBAN LANDSCAPES: RESULTS AND LESSONS LEARNED FROM THE TUCSON BIRD COUNT
Turner, W. R., Conservation International, Washington, DC, United States, firstname.lastname@example.org; McCaffrey, R. E., University of Arizona, Tucson, AZ, United States, email@example.com
As urban populations grow, cities can take on an increasing role in sustaining biodiversity. Yet our cities generally remain inhospitable to most native birds. Long-term data collected throughout a city can aid in developing approaches for sustaining birds in and around urban areas. But long-term, spatially extensive (i.e. citywide) data are scarce. Volunteer-based, citywide surveys offer high-visibility, efficient means to acquire data unobtainable by other methods, presenting great potential to advance conservation and organize urban ecology research. The Tucson Bird Count (TBC) has successfully monitored birds at ~1000 sites throughout Tucson, Arizona and surrounding desert for six consecutive years. The TBC uses a rigorous survey design, producing data of genuine use to scientific research and planning. TBC data have already served many purposes, including scientific research, land-use planning, and conveying ecological issues dramatically to a large local audience. This talk will discuss key results of the TBC to date, including an international study quantifying the extent to which urban humans are separated from biodiversity; particular data needs filled by citywide monitoring programs; logistical and survey-design challenges and their solutions; and the benefits of and potential for a global network of cities with long-term avian monitoring programs. http://www.tucsonbirds.org
CHALLENGES AND BENEFITS OF CITIZEN-BASED BIRD RESEARCH IN AN URBAN ENVIRONMENT
Vargo, T. L., Urban Ecology Center, Milwaukee, United States, firstname.lastname@example.org; Lepczyk, C. A., University of Wisconsin-Milwaukee, Milwaukee, United States, email@example.com; Mueller, W. P., Wisconsin Society of Ornithology and Wisconsin Bird Conservation Initiative, Milwaukee, United States, firstname.lastname@example.org; Boyle, O. D., Wisconsin Department of Natural Resources, Milwaukee, United States, Owen.Boyle@dnr.state.wi.us; Feider, M., Milwaukee Audubon Society, Milwaukee, United States, email@example.com; Guglielmo, C. G., University of Western Ontario, London, Canada, firstname.lastname@example.org; Hartmann, D. A., Riveredge Nature Center, Newburg, United States, email@example.com; Sherkow, A. M., Riveredge Nature Center, Newburg, United States, firstname.lastname@example.org; Vondrachek, S. E., Urban Ecology Center, Milwaukee, United States, email@example.com
Citizen Science, a centuries-old concept, links academic research with people in the community who are trained to become research assistants. One of the biggest challenges is overcoming the misconception in academics that citizen-collected data is unreliable. Therefore, training and coordinating volunteers adds a great deal of time and effort. On the other hand, enlisting citizens allow for sampling larger areas, providing education to the community and gaining local support. Urban areas provide an ideal setting for citizen-based projects such as the Milwaukee County Avian Migration and Monitoring Partnership, which is utilizing citizen scientists to investigate avian migration stopover habitats in an urban environment. The goal is to assess urban habitat patch quality through point-count transects, constant-effort mist-netting, vegetation analysis and blood metabolite analysis on target species. In our first year we have had a large volunteer pool (>50 people) who have collected reliable data on birds and vegetation at eight urban parks during the migration period. However, we have also encountered additional logistic issues and time considerations. Overall, the trade-off in reward to both the scientists and volunteers relative to cost strongly supports the citizen science approach, while at the same time addressing a novel question on urban bird ecology. http://home.earthlink.net/~iltlawas/id16.html
EVALUATING URBAN FOREST FUNCTIONALITY: A THREE DIMENSIONAL APPROACH USING BIRD SPECIES RICHNESS, HOME VALUES, AND RESIDENT SATISFACTION
Oleyar, M. D., University of Washington. College of Forest Resources, Seattle, WA, United States, firstname.lastname@example.org; Withey, J. C., University of Washington, College of Forest Resources, Seattle, WA, United States; Greve, A. I., University of Washington, Dept of Urban Design and Planning, Seattle, WA, United States; Bjorn, A. M., University of Washington, Dept of Urban Design and Planning, Seattle, WA, United States
Urban development often places a significant amount of pressure on forested green spaces and natural areas. While efforts are often made to protect these spaces, many policies and programs focus on a narrow range of goals, rarely considering the multiple functions of forests. We investigate three primary functions for which forests in residential areas are protected and managed along an urbanization gradient in Seattle, WA: economic, ecological, and social. We define economic functionality in terms of the added monetary value of homes directly attributable to nearby forested areas as derived from a hedonic price model. For ecological functionality we evaluate how bird species richness changes along the urban gradient. Finally, we measure social functionality of forests in terms of the non-monetary benefits that people gain from forests, such as resident satisfaction, measured via a mailed survey. Bird species richness and overall resident satisfaction increase as amount of urbanization decreases. The effects that forest size and distribution on the sales price of homes are highest in highly developed areas and undeveloped areas, and are lowest in medium density suburbs. We investigate several regions along the gradient with respect to the relationships between each measure of functionality.
EXPLORING THE ECOLOGICAL CONSISTENCY OF BIRD CONSERVATION REGIONS ACROSS A GRADIENT OF HUMAN DENSITY
Hochachka, W, M, Laboratory of Ornithology, Cornell University, Ithaca, USA, email@example.com; Fink, D.,, Laboratory of Ornithology, Cornell University, Ithaca, USA, firstname.lastname@example.org; Bonter, D. N., Laboratory of Ornithology, Cornell University, Ithaca, USA, email@example.com; Caruana, R. A., Department of Computer Science, Cornell University, Ithaca, USA, firstname.lastname@example.org; Kelling, S. T., Laboratory of Ornithology, Cornell University, Ithaca, USA, email@example.com; Munson, A., Department of Computer Science, Cornell University, Ithaca, NY, USA, firstname.lastname@example.org; Riedewald, M., Department of Computer Science, Cornell University, Ithaca, USA, email@example.com; Sorokina, D., Department of Computer Science, Cornell University, Ithaca, USA, firstname.lastname@example.org
North America has been partitioned into ecologically distinct bird conservation regions (BCRs), which contain similar bird communities, natural habitats, and resource management issues. We explored whether birds perceive differences among BCRs, specifically examining whether the intensity of anthropogenic influence weakened differences among BCRs. The data used in these explorations were winter-long counts of birds at feeders across the United States. For several species, we found that abundances of birds varied across a rural to urban gradient, and that the form of this variation differed among BCRs. However, we found no evidence that more urbanized (and presumably more human-impacted) sites were more homogeneous across BCRs. Thus, BCRs do have ecological meaning even in the face of human alteration of landscapes. We also found that BCRs differed in the relationship between observer effort and the number of birds detected for a given species, which has implications for interpretation of large-scale monitoring data. We further explored whether BCRs could be identified from avian abundance data. While the scope of inference (winter birds at bird feeders) from our analyses is limited, our analytical methods can be used to evaluate the relevance of BCR delineations for data from other sources.
TOWHEE OR NOT TO BE: ARE URBAN SPOTTED TOWHEE POPULATIONS SELF-SUSTAINING?
Bartos Smith, S., Portland State University, Portland, United States, email@example.com; McKay, J.E., Portland State University, Portland, United States, firstname.lastname@example.org; Murphy, M, T, Portland State University, Portland, United States, email@example.com
We have conducted intensive demographic studies of a color banded population of Spotted Towhees (Pipilo maculatus) in 6 greenspaces (range: 1 to 24 ha) within the urban growth boundary in Portland, Oregon, since 2004. Our goal has been to determine whether the local populations breeding in urban habitat fragments are self-sustaining (i.e. source populations; λ ≥ 1) or if they can only be maintained by immigration from outside sources (i.e. sink populations; λ < 1). Preliminary analyses based on two years of data suggest that parks ≤ 10 ha are sinks, while larger parks (>15 hectares) are sources. Towhees are multi-brooded and seasonal productivity/female did not differ among parks of different sizes, but apparent adult survival was significantly lower in the smaller greenspaces. Additionally, nesting success in these urban greenspaces appears to be negatively influenced by distance to recreational trails, but not by distance to habitat edges. Vegetation structure within Portland's parks and greenspaces closely match habitats used outside of urban areas, but an excess of trails and high adult mortality may create "ecological traps" in smaller parks.
SONG SPARROW (MELOSPIZA MELODIA) POPULATION STRUCTURE IN A FRAGMENTED URBAN LANDSCAPE
Unfried, T, M, University of Washington, Seattle, United States, firstname.lastname@example.org
When forests are fragmented by urbanization, songbird reproduction, survival, and dispersal are altered, potentially creating new population structure, such as metapopulation or source-sink population dynamics. I studied Song Sparrows (Melospiza melodia) in the Seattle metropolitan region to determine how forest fragmentation has affected population structure. Point count surveys from 1999-2004 suggest that population changes at 19 sites are uncorrelated, implying independent population dynamics typical of metapopulations. I have collected blood and/or feather samples from 251 Song Sparrows at 25 sites throughout the Seattle region to assess population structure using molecular marker methods. Analysis of a subset of 32 of the samples at three microsatellite loci revealed Weir and Cockerham's theta = 0.065, indicating moderate differentiation among populations, but assignment methods misassigned individuals to populations more than expected. A lack of relation between genetic differentiation and genetic differentiation suggests that factors besides isolation by distance, such as landscape composition, may contribute to population structure. Thus, it is possible that fragmentation has altered Song Sparrow population structure by its affect on dispersal. These results indicate that analysis of larger sample sizes at more microsatellite loci will be a fruitful approach for understanding Song Sparrow population dynamics in urban landscapes.
IDENTIFYING MECHANISMS USING A RURAL TO URBAN GRADIENT PARADIGM
Blair, R, B, University of Minnesota, Saint Paul, United States, BlairRB@umn.edu; Pennington, D, N, University of Minnesota, Saint Paul, United States, email@example.com
Urbanization creates distinct repeatable patterns in the distribution and abundance of birds. Understanding the mechanisms that create these patterns can be a challenge that requires investigation at multiple spatial, temporal, and biological scales. In this talk, we will present work from both terrestrial and riparian rural-to-urban gradients that demonstrates community composition at a specific location is the result of fine-scale processes - such as predation and nesting success - as well as large-scale characteristics � such as landscape heterogeneity and surrounding land use. Additionally, we will explore how life-history and behavioral plasticity allow some species to thrive (or at least exist) in urban settings while limiting the existence of other species.
EXTINCTION, COLONIZATION AND COEVOLUTION: AVIAN RESPONSES TO URBANIZATION
Marzluff, J, M, University of Washington, Seattle, USA, firstname.lastname@example.org
Urbanization reduces, converts, perforates, and fragments native vegetation. It also provides food, water, and shelter for birds. I review some of these processes at national and global scales and detail how they affect bird demography, relative abundance, and community composition in the Seattle metropolitan region. Bird diversity peaks at intermediate levels of human settlement primarily because of the colonization of intermediately disturbed forests by early successional, native species. Extinction of native forest birds and colonization of settlements by synanthropic birds have lesser effects on the overall pattern of avian diversity with respect to the level of urbanization. However, extinction increases linearly with loss of forest and colonization by synanthropic species decreases curvilinearly with reduction of urbanization. It appears that the response of adult survivorship (not reproduction or dispersal) to human activities is an important demographic mechanism determining which species live with or away from people. Intermediate disturbance appears to drive diversity by increasing the heterogeneity of the local land cover. The maintenance of high local and regional diversity will require planning and cooperation among a diverse group of planners, ecologists, policy makers, home owners, educators, and activists so that the same landscapes are not promulgated everywhere. Maintaining high bird diversity and contact with culturally-stimulating species where people live may engage humanity to value nature.
AVIAN RESEARCH IN URBAN ENVIRONMENTS -- WHAT ARE WE RECOMMENDING TO LAND MANAGERS?
Miller, J, R, Iowa State University, Ames, IA, USA, email@example.com
Avian conservation in urban areas has become a major theme in applied ecological research over the last decade. The goal of much of this work is presumably to provide guidance to land managers and planners on ways to improve conditions for native bird species in urban and suburban environments. Too often, however, such management recommendations tend to be somewhat vague or unrealistic. Here, I assess the extent to which the goal of providing sound advice to land managers is being met by examining avian studies conducted in an urban or suburban context that have been published over the last five years. These studies are evaluated on the basis of criteria such as the degree to which specific guidelines are offered and the extent to which the recommendations are actually supported by the data at hand. I also consider how realistic the suggested actions are in terms of monetary costs and other logistical concerns. Finally, I explore the overarching strategies embodied in these recommendations and offer some thoughts on alternative views of conservation in the context of human settlement.
A MULTI-SCALE ANALYSIS OF FACTORS AFFECTING THE OCCURRENCE OF FOREST SONGBIRDS IN AN URBAN LANDSCAPE
Tremblay, M, A, University of Alberta, Edmonton, Canada, firstname.lastname@example.org
Urbanization is predicted to be the single most important driver of extinction this century. Yet, urban landscapes have received relatively little attention by ecologists compared to more natural systems. The purpose of this study is to investigate, at multiple spatial scales, how habitat loss and fragmentation caused by urban development and transportation corridors affect the distribution, diversity, and movements of forest songbirds within a rapidly expanding urban landscape of Calgary, Canada. In 2005, I used audio playbacks of a chickadee mobbing call to lure birds across four types of small-scale features: (1) roads of varying widths and traffic volumes, (2) railways (including transit lines), (3) transportation bridges over riparian corridors, and (4) rivers. My preliminary findings suggest that such features can significantly impede the movements of songbirds, especially as the gap in vegetation exceeds 30 m. These results point to a number of simple and inexpensive strategies (e.g., the inclusion of treed medians along busy roads) for improving the permeability of the urban landscape for forest songbirds. More generally, the project, which is still in its early stages, will lead to the identification of planning strategies aimed at preserving or enhancing avian biodiversity within urban landscapes in North America and elsewhere in the world. http://www.ualberta.ca/~mariet/CHCSPhomepage.htm
SONGBIRD-HABITAT RELATIONSHIPS IN HUMAN-DOMINATED LANDSCAPES OF EXURBAN SOUTHEASTERN MICHIGAN, U.S.A.
Taylor, J, J, University of Michigan, Ann Arbor, USA, email@example.com; Brown, D, G, University of Michigan, Ann Arbor, USA, firstname.lastname@example.org; Lepczyk, C, A, University of Wisconsin - Milwaukee, Milwaukee, USA, email@example.com
The fundamental goal of our research is to investigate the ecological effects of human-induced landscape alterations at the urban-rural interface. Our first research objective seeks to answer the question "how have historical landscape changes affected avian populations at the urban-rural interface in Southeastern Michigan?' To answer this question we used land-cover interpretations completed during Project SLUCE at the University of Michigan and avian data from the North American Breeding Bird Survey (BBS) from 1970-2000. Utilizing both the landscape and BBS data, we analyzed guild-level responses of breeding birds to land-cover changes within the region. The most notable of our results indicate that between 1970 and 2000 agricultural lands have decreased by an average of 52% while the average amount of tree cover and the number of human settlements increased by 87% and 99%, respectively. Concurrently, the average number of grassland species counted per survey declined in each decade while woodland species remained relatively constant. These results suggest that agricultural row crops may serve as a surrogate habitat for grassland species, and that factors other than the area of tree cover influence the number of woodland species present at our sample sites.
FUTURE CHANGES IN BIRD DIVERSITY RESULTING FROM PREDICTED CHANGES IN LAND COVER IN THE CENTRAL PUGET SOUND, WASHINGTON, USA
Hepinstall, J, A, University of Washington, Seattle, United States, firstname.lastname@example.org; Marzluff, J, M, University of Washington, Seattle, United States, email@example.com; DeLap, J, H, University of Washington, Seattle, United States, firstname.lastname@example.org; Alberti, M, , University of Washington, Seattle, United States, email@example.com
Models that predict land use and land cover change and resulting change to biodiversity are needed to support regional planning and conservation efforts. Our approach links urban development, land cover change, and bird diversity and explore dynamic interactions in the rapidly urbanizing landscape of the Central Puget Sound, Washington, USA. We use a microeconomic development model of human behavior (UrbanSim), coupled with a land cover change model (LCCM) to predict land cover change. The LCCM includes measures of the present land cover class of the focal cell, its spatial context and the spatial pattern of development and biophysical elements at three spatial scales. The LCCM predicts potential land cover change in 4 year intervals for 20 years into the future, which are then used as input in bird diversity models generated from 5 years of extensive field studies across the urban and land use gradients. Results indicate that changes in land cover can be expected to continue the conversion of bird communities dominated by native forest species to those dominated by early successional and synanthropic species. Local bird diversity on developed sites increased, but regional diversity declined as developments aged due to biotic homogenization.
SEPARATING THE EFFECTS OF DIFFERENT COMPONENTS OF URBANIZATION ON AVIAN ASSEMBLAGES
Fuller, R, A, Biodiversity & Macroecology Group, Dept of Animal & Plant Sciences, University of Sheffield, Sheffield, UK firstname.lastname@example.org; Warren, P, H, University of Sheffield, Sheffield, UK; Arnsworth, P, R, University of Sheffield, Sheffield, UK; Barbosa, O, University of Sheffield, Sheffield, UK; Davies, R, G, University of Sheffield, Sheffield, UK; Tratalos, J, , University of Sheffield, Sheffield, UK; Gaston, K, J, University of Sheffield, Sheffield, UK
Owing to rapid growth and urbanization of human populations, many decisions by policy-makers focus on how, rather than whether to urbanize. However, our understanding of factors affecting the distribution of biodiversity within cities is much more limited than our knowledge of the general effects of urbanization on previously rural areas. Using data collected at three scales within the UK, we studied the effects of various components of the pattern of urbanization within cities on avian assemblages with a view to informing the policy debate. For example, we show that densities of many species listed as urban sustainability indicators are strongly associated with housing density, at first increasing, but then declining markedly at or below the housing density at which new developments are currently required by central government. In the city of Sheffield, species rich samples tended to be in areas of middle or high income groups in low density, suburban settings. Our data highlight the difficulties of maintaining urban biodiversity, and human contact with urban biodiversity, while minimizing land take for new development. High density urban developments are associated with declines in many of those species otherwise best able to exploit urban environments, including species that are indicators of sustainability.
EFFECTS OF LAND-USE INTENSITY AND FOREST PATCH COMPLEXITY ON AVIAN DIVERSITY IN AN URBANIZED TROPICAL ISLAND LANDSCAPE
Suarez-Rubio, M, , National Zoological Park, Front Royal, VA, USA, email@example.com;Thomlinson, J, R, California State University, Dominguez Hills, USA, firstname.lastname@example.org
An accelerating pattern of urban development is one important factor affecting bird populations. In Puerto Rico, only 1.2 % of the moist evergreen forests on the island are protected. Generally, these forests occur at the lowest elevations where rates of land-cover conversion to urban areas are highest. Puerto Rico provides a unique opportunity to assess how the spatial arrangement of urban forest patches and the interior patch structure influence the bird communities within a range of urbanization intensity. Landscape as well as the interior patch structure is influencing the bird communities. Bird assemblages differed along the urban-suburban gradient in Puerto Rico: some species were relatively unaffected by urbanization, while several increased in abundance with increased urbanization and some were sensitive to even minor disturbances by urban development. It is important to understand the sensitivity of particular bird species to habitat degradation in the urban-rural interface, areas that in Puerto Rico are used by both endemic and Neotropical migrant species. Identifying the importance of forest patches for these groups of birds will greatly aid in their conservation. In addition, we are identifying those species that are particularly sensitive to fragmentation, so that these can be used as bio-indicators of environmental health.
AVIFAUNA SURVEYS IN THE CITY OF PUEBLA AND SURROUNDINGS: ADVANCES AND PRELIMINARY RESULTS
Gonzalez-Oreja, J, A, Universidad de las Americas Puebla, Cholula, Puebla, Mexico, email@example.com; Bonache-Regidor, C Buzo-Franco, D, , Texas State University, San Marcos, TX, USA, firstname.lastname@example.org; de-la-Fuente-Diaz-Ordaz, A, A, Hernandez-Santin, L, , Sul Ross State University, Alpine,TX, USA, email@example.com
Urbanization can provoke disappearance of a high number of species in the future; however, many bird species have been able to adapt to the cities' environmental conditions. What traits allow the adaptation? What is the bird community structure in urban environments? What are their population dynamics? To answer these and other questions, we conducted a mid-term survey on the city of Puebla, Mexico and its surroundings. We determined the composition of the bird community in 21 green spaces, and we studied the temporal dynamics of bird populations in 7 of these sites. Additionally, we differentiated urban bird species as a function of their diet, body size, and phenologic regime. Furthermore, we use linear regression models to explain species richness of the sites as a function of environmental variables (area, source distance, environmental disturbance caused by noise). Finally, we found nestedness patterns of the community structure of the study site, and we examined the reasons likely to promote these patterns. Our study presents current results obtained.
SHIFTS IN AVIAN COMMUNITIES ASSOCIATED TO URBANIZATION IN A MOUNTAIN SUBTROPICAL AREA
MacGregor-Fors, I, , Centro de Estudios en Ecosistemas, UNAM, Morelia, Mexico, firstname.lastname@example.org; Morales-Perez, L, , Centro de Estudios en Ecosistemas, UNAM, Morelia, Mexico, email@example.com; Schondube, J, E, Centro de Estudios en Ecosistemas, UNAM, Morelia, Mexico, firstname.lastname@example.org
The effects of urbanization on avian communities have been widely studied on temperate regions (i.e. United States, Canada), yet our understanding of the same processes in tropical areas is rudimentary. If we pretend to maintain diverse and healthy avian communities in cities, we need to know the effects of urbanization processes on bird population parameters. In this study we explored the effects of urbanization on the avian communities within Morelia, a city located in a mountain subtropical forest matrix (interface between mixed pine tree-oak forest and dry tropical forest) in Michoacan, Mexico. Our research evaluated landbird richness and abundance (secondary population parameters) along an urban gradient by using fixed radius point counts. The urbanization gradient we studied expands from well-preserved forests sites in rural areas, to sites of high urban development in Morelia's downtown. Our results show that species richness is inversely related to urbanization degree, while total bird density increases with it. Also, we found that urban parks with different plant composition and structure present different ensembles of birds, with parks dominated by native trees having more complex bird communities than parks planted with introduced species of plants.
DO URBAN AREAS ACT AS A REFUGE FROM NEST PREDATION FOR AN URBAN "WINNER", THE NORTHERN MOCKINGBIRD (MIMUS POLYGLOTTOS)?
Stracey, C, M, University of Florida, Gainesville, USA, email@example.com; Robinson, S, K, University of Florida, Gainesville, USA, firstname.lastname@example.org
Urban environments are characterized by reduced avian species richness and evenness. Most urban studies focus on species that disappear or decline. Yet community-wide abundance and biomass is often greater in urban environments because a few, usually large species tend to become dominant. I investigated one possible mechanism underlying the increase in abundance of one of the urban "winners", the Northern Mockingbird (Mimus polyglottos) in Gainesville, FL, where census data show that mockingbirds are twice as abundant as they are in nearby non-urban habitats (natural areas and pastures). I collected data on nest predation rates to asses the hypothesis that a decrease in nest predation in urban areas leads to an increase in the abundance of mockingbirds. In Gainesville, urban areas have enhanced populations of avian predators, but data on abundance of some major nest predators (e.g. snakes) remain difficult to obtain and cannot be assessed using artificial nests. Therefore, to assess nest predation rates, I located and monitored nests of mockingbirds in three types of habitat: parking lots, residential areas, and natural areas. Nest predation rates were significantly higher in natural areas than in either parking lots or residential areas: 54%-57% of nests in parking lots and residential areas were depredated, compared with 86% of nests in natural areas. I also monitored nests of Northern Cardinals (Cardinalis cardinalis) and Brown Thrashers (Toxostoma rufum) to determine if there were consistent patterns in nest predation rates for different species. Predation rates for both of these species followed the same pattern as nest predation rates of Northern Mockingbirds. These results are consistent with the hypothesis that nest predation rates in urban areas are lower than in non-urban areas, providing, at least for some species, a refuge from predation. The species that are able to exploit this refuge may be species that can aggressively defend their nests from abundant avian predators. http://www.flmnh.ufl.edu/ordwaylab/index.html
MIGRATORY STOPOVER DURATION AND MOVEMENT OF SWAINSON'S THRUSHES IN AN URBAN LANDSCAPE
Matthews, S, N, The Ohio State University, Columbus, United States, email@example.com; Rodewald, P, G, The Ohio State University, Columbus, United States, firstname.lastname@example.org
Long distance migration involves the use of multiple stopover sites where avian migrants must refuel to meet high energetic demands. Urbanization may pose a considerable challenge to a bird�s ability to regain fuel. Using an experimental approach we studied habitat utilization and behavioral decisions of migrating Swainson's Thrushes within urban areas of Columbus, Ohio. During May of 2004 and 2005, we caught 49 Swainson's Thrushes (Catharus ustulatus) in a woodlot on the Ohio State University campus and fitted each with a radio transmitter. To simulate arrival of a migrant at a new stopover location, we relocating thrushes to one of 6 predetermined locations. Birds were monitored throughout their stopover to quantify stopover duration and movement patterns of individuals. Mean stopover duration was 5 days (sd=3.3) and ranged from 1 to 12 days. There was a significant negative relationship between stopover duration and energetic condition at capture (p=0.013). While there was no significant influence of stopover site on duration, we detected a positive relationship between distance moved per day and the area of the stopover site (p=0.014). These results indicate that Swainson's Thrushes are more limited in their movements in more fragmented urban landscapes.
AMERICAN CROW NESTLING GROWTH AND NUTRITIONAL STATE VARY WITH HABITAT
Heiss, R, S, Binghamton University, Binghamton, USA, email@example.com; Clark, A, B, Binghamton University, Binghamton, USA firstname.lastname@example.org; McGowan, K, J, Cornell Lab of Ornithology, Ithaca, USA, email@example.com
In urbanized areas many birds find sufficient foods to survive. Human foods, however, may have a negative effect on growing nestlings. We hypothesized that suburban American Crow (Corvus brachyrhychos) nestlings are nutrient limited relative to rural birds. We tested the nutritional and physiological health of nestlings by measuring plasma calcium, total serum protein, corticosterone, and growth. We quantified habitats in known crow territories and distinguished three distinct environments: suburban-residential, suburban-managed (e.g., golf courses) and rural. Nestlings in each environment were measured and bled between 24 and 30 days of age. We supplemented a subset of territories with a high protein and calcium food. Rural nestlings were significantly larger than suburban-residential birds, and had higher serum total protein. Nestlings in suburban-managed areas were intermediate in those measures, but had the lowest plasma calcium levels. Neither condition nor corticosterone levels differed significantly between habitats indicating that suburban nestlings were not near starvation. Supplemented nestlings in suburban-residential areas had significantly larger tarsi and bills than their unsupplemented counterparts, while unexpectedly, supplemented rural nestlings were significantly smaller than unsupplemented rural ones. Our results suggest that the foods available in urbanized areas are worse for the development of nestling crows than foods in rural areas.
TOWARDS A MECHANISTIC UNDERSTANDING OF URBAN-ASSOCIATED CHANGES IN BIRD COMMUNITIES
Rodewald, A, D, The Ohio State University, Columbus, USA, firstname.lastname@example.org
Although urban-associated changes in avian communities are frequently documented, most studies fail to identify underlying mechanisms. Using avian communities in riparian forests of Ohio as a model system, I examined if changes in bird communities along a rural-urban gradient were more strongly linked to demographic or behavioral processes. From 2001-2005, I sampled bird communities at 33 sites, monitored 1759 nests, and banded 177 Acadian Flycatchers and 327 Northern Cardinals to monitor condition, annual survival, and season-long productivity. Food resources, microclimate conditions, habitat characteristics, and numbers of nest predators also were measured. Most resident species were positively related to urbanization, whereas most Neotropical migrants were negatively related to urbanization. Mechanisms producing these patterns were less clear. Although winter temperatures, fruit abundance, exotic shrubs, bird-feeders, and numbers of nest predators were positively related to urbanization, avian demographic parameters were less predictably linked to urbanization in the surrounding landscape. Nest depredation rates, though generally greater in urban than rural landscapes, were spatially and temporally variable. Productivity and survival data also weakly supported the demographic hypothesis for urban-associated changes in bird communities. Instead, behavioral processes, such as settlement biases, provide better a mechanistic understanding of urban-induced changes in bird communities.
BREEDING BIOLOGY OF STERNA ANTILLARUM ATHALASSOS NESTING IN URBANIZED AREAS OF NORTH CENTRAL TEXAS
Boylan, J, T, Dallas Zoo, Dallas, TX, USA, email@example.com; Bocanegra, O, , U.S. Fish and Wildlife Service, Arlington, TX, USA, Omar_Bocanegra@fws.gov
Natural habitat for interior least terns Sterna antillarum athalassos is now virtually absent in north central Texas. However, terns have initiated breeding colonies in non-traditional habitats. In 1991, a colony of terns began using sludge fields at a wastewater treatment plant for nesting sites. In 2001, we documented the first incidence of a S. a. athalassos colony using a warehouse rooftop as a nesting site. We began an intensive monitoring project in 2001 to determine the reproductive success of these novel types of habitats. Colony sites within habitats usually changed yearly and the reproductive success of the various locations was highly variable. Weather seemed to influence some locations but not others. Number of eggs per nest was correlated with date of nest initiation. These results are comparable with other published data even though the causes of reproductive failure may be different.
JUVENILE BURROWING OWL MOVEMENT, HABITAT USE, AND SURVIVAL IN AN URBAN MATRIX
Grandmaison, D, D, Arizona Game and Fish Department, Phoenix, USA, DGrandmaison@azgfd.gov; Ingraldi, M, F, Arizona Game and Fish Department, Phoenix, USA,
Development in Tucson, Arizona, USA has led to concern regarding the status of the local burrowing owl population. Western burrowing owls living and breeding within the Tucson Basin face the challenge of dispersing through an urban matrix where natural burrows are becoming increasingly scarce. In an effort to identify dispersal corridors, we monitored post-fledging movements of 18 radio-marked juvenile burrowing owls, evaluated habitat use associated with these movements, and estimated juvenile survival during the 2004 2005 dispersal period. Eleven of the 18 radio-marked juveniles made post-fledgling movements of over 1 kilometer. Two individuals made long-distance movements of more than 30 kilometers. Dispersing juveniles utilized a wide range of urban habitats although many movements were associated with the Santa Cruz River. Cumulative weekly survival of radio-marked juveniles at the end of the monitoring period was approximately 70%. Our results indicate that dispersal movements through the Tucson metropolitan area are possible and implicate the Santa Cruz River as an important geographic corridor that may help facilitate urban burrowing owl population persistence.
RANGING BEHAVIOUR OF COMMON KESTRELS (FALCO TINNUNCULUS) ON URBAN-RURAL GRADIENT
Mikes, V, , University of South Bohemia, Česke Budějovice, Czech Republic, firstname.lastname@example.org; Riegert, J, , University of South Bohemia, Česke Budějovice, Czech Republic, email@example.com; Fuchs, R, , University of South Bohemia, Česke Budějovice, Czech Republic, firstname.lastname@example.org
Common Kestrel (Falco tinnunculus) is a small falconid bird of prey, which feeds predominantly on voles and successfully colonized urban areas of Europe. These times, the highest breeding densities of kestrels are regularly ascertained in the centres of big European cities. Generally, synurbic populations of birds are known as different, in some aspects, of natural populations. One of the least known aspects of the synurbic populations of kestrels is their territorial and ranging behaviour. The wing-tagging and the radio-tracking of breeding kestrel males from variously urbanized environments (city centre, outskirts and farmland) enabled us to study this problem. During the breeding seasons 2002-2005 we determined the home range size of 63 kestrel males in total. The home range size of kestrel males breeding in the city centre was multiple larger than of the city outskirt males or the nearby farmland kestrels. Kestrels from farmland were strictly territorial, while the kestrels breeding in the city centre shared most of their home ranges each other. We discuss possible reasons for this home range arrangement and we emphasize to the density dependent hypothesis.
DISTRIBUTION OF RIPARIAN BIRD SPECIES IN AN URBANIZING LANDSCAPE
Oneal, A, S, University of California, Riverside, USA, AmberSOneal@aol.com; Rotenberry, J, T, University of California, Riverside, USA, John.Rotenberry@ucr.edu
In coastal southern California, natural riparian corridors occur within a landscape mosaic comprised of anthropogenic land uses and undeveloped native shrublands. We surveyed 137 points in riparian vegetation along an urbanization gradient to assess bird species distribution with respect to local vegetation variables and/or the amount of development in the landscape. We used logistic regression and information theory to select the best supported model describing the distribution of each bird species. Of 52 species with sufficient detections to analyze, 49 had statistically significant (P < 0.05) models. Models based only on local-scale vegetation variables were best supported for 25 species, whereas landscape-scale (amount of urbanization) models were best supported for 15. Nine species were best predicted by models that included local and landscape variables. The only consistent response within guilds was that woodland species responded to local variables while scrub species appeared more sensitive to the landscape variable; no other habitat, foraging, nesting, or migratory guilds demonstrated patterns. The landscape matrix appeared to influence some bird species occurrences; however, the best scale to predict species occurrences varies by species. When determining the best reserve design for the riparian bird community, both the local and landscape-scale variables should be included.
EFFECTS OF HYDROLOGY AND URBANIZATION ON SHOREBIRDS OF THE ELLA BARNES WETLAND, OSO BAY, CORPUS CHRISTI, TEXAS
Smith, L, C, Texas A&M University-Corpus Christi, Corpus Christi, United States, email@example.com; Smith, E, H, Texas A&M University-Corpus Christi, Corpus Christi, United States, firstname.lastname@example.org
Tidal flats in the Texas Coastal Bend region are important for many Western Hemisphere migrating shorebirds. A large portion of the Oso Bay watershed has been increasingly urbanized within the city limits of Corpus Christi resulting in increased freshwater and saltwater effluent. Shorebird abundance and distribution were determined on the Ella Barnes Wetland to establish hydrology and the extent and usage of tidal flats on this urbanizing wetland. Birds were censused using 15-minute point counts every 7-10 days from February 2004 to February 2005. Seven species, three groups, and 1123 individual shorebirds were documented throughout the study. Calidris spp. and killdeer were most abundant, whereas Calidris spp. and dowitchers were more predominant when compared to three previous studies in the same bay system. Willets, black-necked stilts, Calidris spp., and killdeer spent significantly more time on exposed habitat while only _Calidris_ spp. spent significantly more time feeding. Identification and conservation of remaining tidal flats is vital to shorebirds. Although species richness and density were lower at the Ella Barnes wetlands, they were still used by migrating shorebirds under certain conditions. Therefore, future research and management should be planned and implemented to cover all bird habitats throughout the Oso Bay system.
SITE FIDELITY AND POPULATION TENDENCIES OF URBAN BIRDS OF OAXACA, MEXICO
GROSSELET, M, , PERSONAL, OAXACA, Mexico, email@example.com; Gonzalez Robles, R, O, UAM, MEXICO CITY, Mexico, firstname.lastname@example.org
After more than 5 years of monitoring the birds of the center of the city of Oaxaca by mist-nets, the first data on the population tendencies of migratory and resident bird species are presented. Additionally, site fidelity data for the migratory species are presented.
EFFECT OF LANDSCAPE STRUCTURE ON BIRD COMMUNITIES IN TWO SUBTROPICAL FORESTS OF NORTHERN TAIWAN
Cheng, Y, R, University of Montana, Missoula, United States, email@example.com; Lee, P, F, National Taiwan University, Taipei, Taiwan ROC, firstname.lastname@example.org
Landscape structure is an important factor to predict community structure. Most of the studies have shown how these landscape characteristics such as vegetation type, patch dynamics, and edge effect interplay to affect community structure. However, the effect of vertical structure (topography) in landscape, which is a spectacular feature in many regions, is less emphasized. We investigated the two bird communities with point count method in two isolated mountainous areas (Snow Mountains and Tatun Mountains) in Taiwan. Though the two plots have the similar vegetation type (subtropical broad-leaf forest) and elevational range (600-850m), the results in cluster analysis and detrended correspondence analysis (DCA) revealed that the two bird communities were distinctly different, especially in the non-breeding season. The regional topography surrounding the plots and the vegetation structures in a larger scale were suggested to be the process in the pattern. In contrast with the plot in Tatun Mountains where the highest peak is only 1,120m, the plot in Snow Mountains was surrounded with many peaks higher than 2,000m and was added the mid-elevational species through altitudinal migration in the non-breeding season. To better predict bird community structure, we should consider the effect of regional topography and seasonal change.
NEST-SITE SELECTION AND NEST SUCCESS OF BIRDS ON MONTREAL-AREA GOLF COURSES AND GREEN SPACES
Hudson, M, A, McGill University, Montreal, Canada, email@example.com; Bird, D, M, McGill University, Montreal, Canada, firstname.lastname@example.org
In an increasingly urbanized landscape, suburban golf courses have the capacity to serve as important sanctuaries for wildlife. Considering that the average 18-hole course covers approximately 54 hectares, and that there are well over 31,500 golf courses worldwide, the capacity for wildlife habitat is immense. Recently published research has highlighted this potential, though the results are highly species- and site-specific. The objectives of this study were to: i) calculate and compare reproductive success and predation rates of open-cup nesting passerines on golf courses and green spaces; ii) compare avian species richness between habitats; iii) examine nest-site and nest-patch selection of 4 species common to these sites, American Robin (Turdus migratorius), Gray Catbird (Dumetella carolinensis), Northern Cardinal (Cardinalis cardinalis), and Chipping Sparrow (Spizella passerina); and iv) test a new computerized camera system designed for monitoring nests in densely-leafed trees, shrubs, and emergent vegetation. This camera system allows the researcher to quickly capture high-quality colour images that are easily archived and accessible. In addition to nest monitoring and examining nest-site selection at 6 focal sites (4 golf courses and 2 green spaces), intensive breeding bird surveys were also conducted at 14 sites in the Montreal area to investigate to what degree urban fragments support different breeding bird communities. During the course of the 2003-2005 field seasons, almost 900 nests of 19 open-cup nesting species were located and monitored, and 111 nests and associated non-nest sites were examined.
COOPER'S HAWK NESTING DENSITIES IN AN URBAN INTERFACE WOODLAND IN CENTRAL NEW MEXICO
Garber, G, L, Hawks Aloft, Inc., Albuquerque, NM, USA, email@example.com; Fetz, T, W, Hawks Aloft, Inc., Albuquerque, NM USA firstname.lastname@example.org; Stake, M, M, Hawks Aloft, Inc., Albuquerque, NM, USA, email@example.com; DeRagon, W, R, US Army Corps of Engineers, Albuquerque, NM, USA, firstname.lastname@example.org
Cooper's Hawks (Accipiter cooperii) breed in a variety of forested habitats, and high densities have been documented in urban areas. In 2004 and 2005, we documented breeding activity of Cooper's Hawks in 70 km (2031ha) of riparian woodlands (bosque) along the Rio Grande, near Albuquerque, New Mexico, to determine what factors contribute to high densities. We found 1.34 active nests per 40ha (n=136), although there were differences among reaches. The Corrales section supported 2.50 active Cooper's Hawk nests per 40ha, among the highest densities reported in North America. Some nests were less than 150m apart. The Albuquerque and Los Lunas sections supported fewer nesting pairs, 1.44 and 0.64 active nests per 40ha, respectively. We suggest that nest densities in Corrales were associated with increased prey availability. In a concurrent study, we found greater songbird abundance in Corrales. Numerous feeding stations in large, adjacent residential properties may have attracted greater avian and mammalian prey. In Albuquerque, prey base was likely affected by mechanical understory clearing in the bosque. The urban and agricultural matrices in Albuquerque and Los Lunas, respectively, support suboptimal prey populations. Therefore, even in a metropolitan area, landscape and management practices can affect nesting Cooper's Hawks. http://www.hawksaloft.org
REPRODUCTIVE TIMING OF RESIDENT AND MIGRANT SONGBIRDS ACROSS AN URBAN TO RURAL GRADIENT IN CENTRAL OHIO, USA
Shustack, D, P, The Ohio State University, Columbus, United States, email@example.com; Rodewald, A, D, The Ohio State University, Columbus, United States, firstname.lastname@example.org
While most investigations of the impact of urbanization on birds focus on changes in community composition or nesting success, at an even finer and less obvious scale, the timing of reproduction also may be mediated by urbanization. Advanced reproductive phenology has been noted in urban bird populations compared to rural populations, primarily for residents or short-distance migrants. Even fewer studies focus on breeding phenology in long-distance migrants, in part because factors often suggested to be the proximate causes of earlier reproductive timing in urban areas act primarily during the time leading up to reproductive readiness (e.g., in the winter) when long-distance migrants are absent. Our study aims to understand how urbanization influences reproductive phenology of both resident and long distance migrant species. We examined reproductive timing across riparian forests ranging from urban to rural landscape matrices in Ohio. We detected small, but potentially important, differences in the timing and length of the nesting season across the rural-urban gradient. For the resident species, breeding occurred earlier in urban areas, whereas the opposite was true for long-distance migrants. Because breeding phenology can constrain number of nesting attempts within a season, these differences may have important population-level consequences.
AMERICAN CROWS RESPOND TO LOCAL LAND COVER AND LAND USE IN URBANIZING LANDSCAPES
WITHEY, J, C, UNIVERSITY OF WASHINGTON, SEATTLE, United States, JWITHEY@U.WASHINGTON.EDU; MARZLUFF, J, M, UNIVERSITY OF WASHINGTON, SEATTLE, United States, CORVID@U.WASHINGTON.EDU
American Crows use a variety of natural and anthropogenic habitats. I studied how the type of land cover and land use measured at two scales (in 20 m pixels and within a 240 m radius) affected crow abundance in urbanizing areas near Seattle, Washington, U.S.A. My predictions based on previous studies were that crows would be associated with more-open areas (impervious surfaces and grass and shrubs), edges of forests, and in more-fragmented landscapes typical of human settlement. However, crows were positively associated with all three of the local land cover types (impervious surfaces, grass and shrubs, and trees and forests) included in the resource utilization function I used for analysis. Landscape-scale metrics related to fragmentation (number of patches, contrast-weighted edge, and the interspersion of patches) were negatively associated with crow abundance. However, crow use was also negatively associated with the amount of forest in the landscape, and positively associated with the amount of anthropogenic cover (land cover and land uses that are more likely to provide food such as roads, homes and retail businesses, and maintained grass/shrubs/trees typical of parks and yards).
GRASSROOTS ALL-BIRD CONSERVATION IN HUMAN-DOMINATED LANDSCAPES
Fergus, R, , National Audubon Society, Ivyland, PA, United States, email@example.com; Present, T, , National Audubon Society, Ivyland, PA, United States, firstname.lastname@example.org; Butcher, G, , National Audubon Society, Washington, DC, United States, email@example.com; Green, P, , National Audubon Society, Ivyland, PA, , firstname.lastname@example.org; Cecil, J, , National Audubon Society, Ivyland, PA, United States, email@example.com
While integrated bird conservation can become an agency-driven exercise in top-down planning and management, effective conservation needs public buy-in and participation to produce meaningful results in human-dominated landscapes. By encouraging individuals and communities to target their conservation efforts to species of local, regional, and global conservation concern, National Audubon Society programs promote an integrated all-bird approach at a grassroots level. Our aim is to address the needs of these species across a gradient of urban, suburban, and exurban habitats through conservation actions, and to monitor the impacts of these efforts on the species of concern. We integrate these activities with site-based conservation at Important Bird Areas, and bird monitoring efforts such as Audubon's Christmas Bird Count, and cooperative programs including the Audubon/Cornell Great Backyard Bird Count and eBird. These home- and community-based bird conservation planning, habitat management, and bird monitoring activities are creating a grassroots network of people working to conserve birds in urban, suburban, exurban, and rural working lands in ways that are integrated with regional and global all-bird conservation efforts. http://www.audubonathome.org
COLONIAL BIRDS ON URBAN ISLAND AS INDICATORS OF ECOSYSTEM HEALTH
Burger, J, , Rutgers University, Piscataway, United States, firstname.lastname@example.org; Gochfeld, M, , UMDNJ-Robert Wood Johnson Medical School, Piscataway, United States, email@example.com
As human populations continue to concentrate along coasts, there is increasing interaction between people and birds. This trend will continue, and ornithologists must devise ways for birds and people to co-exist. Increasingly birds are exposed to a multiple stressors at the same time in coastal environments, and each one exerts an incremental influence on reproductive success. On top of human disturbance, are the effects of habitat loss, fisheries take, and increasing pollution from urbanization and suburbanization. With changes in energy policy, there are changes in atmospheric deposition of chemicals, such as mercury, which have major implications for biodiversity of nesting birds. Seabirds are excellent bioindicators because they are long-lived, feed at different trophic levels, are at the top of the food chain, and many are abundant and widely distributed. They can reveal spatial or temporal trends in contaminant levels. We examined temporal trends in the levels of cadmium, lead, and mercury in eggs from common terns (Sterna hirundo) nesting on several salt marsh islands in Barnegat Bay, New Jersey. Levels were highest for mercury, followed by lead. The eggs of Barnegat Bay common terns show a decline in levels of cadmium and lead. Mercury declined from 1971 to 1982, increased dramatically in 1999, then initially declined but have started to increase (perhaps due to the relaxation of standards for power plants). The data indicate that common terns can serve as useful bioindicators of temporal trends in exposure, and that some of the metals of concern in estuarine environments (lead, cadmium) have declined over the last thirty years, although mercury levels are higher than in the early 1980s. The effects of contaminants, such as lead, influence a wide range of behaviors such as begging, walking, thermoregulation, and individual recognition, as demonstrated by experimental work with Herring Gulls.
A TERN FOR THE BETTER -- COLONIAL SEABIRDS ON AN URBAN ISLAND IN THE LOS ANGELES HARBOR
Keane, K, M, Keane Biological Consulting, Long Beach, USA, firstname.lastname@example.org; Collins, C, T, California State University, Long Beach, Long Beach, USA, email@example.com; Appy, R, , Port of Los Angeles, Los Angeles, USA, firstname.lastname@example.org
The Port of Los Angeles is required, through a Memorandum of Agreement (MOA) with the U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers and California Department of Fish and Game, to maintain 15 acres of protected nesting habitat for the California Least Tern (Sterna antillarum browni), federally- and California-listed as endangered. However, prior to 1997, California Least Tern (CLT) nest numbers at the Port ranged annually from 0 to 134 (mean = 42) because of predation and fluctuations of CLT productivity throughout the state. In 1997, the Port began construction of a new island for a container terminal. The island, Pier 400, was created to support a container terminal using a perimeter of rock barged from Catalina Island 20 miles offshore and filled with material dredged from the harbor. A new CLT nesting site was provided on the island, which supported 105 CLT nests the first year, and CLT nest numbers increased to 1,331 in 2005. In addition, other tern species began nesting each year within and adjacent to the CLT nesting site; maximum annual nest numbers were over 10,000 for Elegant Terns (Sterna elegans) and 565 for Caspian Terns (Sterna caspia). Colonization of the island by these colonial waterbirds, and their nest numbers, productivity and management methods will be discussed in this presentation.
CONTAMINANT LEVELS AND ASSOCIATED BIOLOGICAL EFFECTS IN HERRING GULLS (LARUS ARGENTATUS) AT URBAN AND NON-URBAN SITES ON THE N. AMERICAN GREAT LAKES, 1981-2005
Weseloh, D, V, Canadian Wildlife Service, Toronto, Canada, email@example.com; Shutt, J, L, Canadian Wildlife Service, Ottawa, Canada, firstname.lastname@example.org; Hebert, C, E, Canadian Wildlife Service, Ottawa, Canada, email@example.com
The Herring Gull has been used as an indicator of environmental health on the Great Lakes since the early 1970s. Fourteen sites from throughout the Great Lakes have been sampled annually since 1981. Most sites (57.1%) were located in non-urban areas (<100,000 people); 42.9% were urban. Sampled parameters included: contaminants in eggs, population size, embryonic mortality, reproductive success, sex ratios at hatch, presence of vitellogenin in adult males, stress response tests, clinical chemistry, etc. Concentrations of four contaminants (PCBs, DDE, HCB and 2378-TCDD) ranged from 1.48 to 2.84 times greater in gull eggs from urban sites. From 1981 to 2005, the decline in contaminant concentrations among the 4 contaminants was similar: 65.8 to 97.7% at urban sites and 62.5 to 97.3% at non-urban sites. Only PBDE levels have increased. Between types of sites, the average difference in per cent declined was only 1.3%. Breeding Herring Gull populations at non-urban sites averaged 8.7x larger than at urban sites. Between the 1980s and the 1990s, non-urban populations were stable, growing by only 1.7%; urban populations grew by 35.6%. Although some non-urban sites supported substantially fewer than 100,000 people, they were located downstream from urban industrialized areas and had negative health measures. In this way, colonial waterbirds reflected true environmental conditions, regardless of the immediate human population or degree of apparent industrialization.
FORAGING ECOLOGY AND HEALTH ASSESSMENTS OF BLACK-CROWNED NIGHT-HERONS IN THE NEW YORK/NEW JERSEY HARBOR ESTUARY: LINKING RESOURCE USE AND WADER HEALTH
Bernick, A, J, City University of New York-Graduate Center, New York City, USA, firstname.lastname@example.org; Newman, S, , Wildlife Trust/Wildlife Conservation Society, Rome, Italy, email@example.com; Padula, V, , Columbia University/Wildlife Trust, New York City, USA, firstname.lastname@example.org
Over 1,700 pairs of colonial wading birds (e.g. herons, egrets, and ibis) breed and forage in the industrialized ecosystem of metropolitan New York City. The Black-crowned Night-Heron (BCNH), a mainly nocturnal forager, is the numerically dominant breeding wader in these colonies. Through foraging surveys on Staten Island, NY (2002-2005) and health assessments of nestlings reared at two colonies (Hoffman and North Brother islands, 2004-2005), we determined that: (1) BCNHs use a wide range of marine, freshwater, and terrestrial habitats in this urban system; (2) BCNHs use different foraging techniques in different habitats, capturing more, smaller prey in coastal habitats and fewer, larger prey items in fresh water; and (3) nestlings from Hoffman Island in 2004, likely provisioned by adults foraging near Staten Island, showed significantly different concentrations of enzymes, proteins, and electrolytes than chicks reared on North Brother Island or Goose Island, or from chicks reared on Hoffman Island in 2005. This suggests that in 2004, prey resources contributed to a significantly different physiological health for chicks from Hoffman Island. As local foraging resource quality influences both the health of adults and nestling BCNHs and the persistence of breeding colonies, understanding the link between adult resource use and nestling health is critical to the protection and conservation of urban wading bird species.
Papers not directly focused on urban ecology, but with urban ecology applications
WARBLER HABITAT DEGRADATION ACCELERATED BY INVASIVE PLANTS
McDonald, M, V, Smithsonian Conservation and Research Center, c/o Dept Biology, Univ Central Arkansas, Conway AR, United States email@example.com
Habitat data on invasive plant species have been taken as a part of an ongoing study of Kentucky Warbler demography and behavioral ecology. Since beginning the long-term population study project in 1979, habitat choice and nesting success of KEWAs and other targeted forest and edge-dwelling migrant and resident bird species have been studied continuously at the Smithsonian Conservation and Research Center near Front Royal, Virginia. The overall population numbers as well as the density (birds per ha) of Kentucky Warblers and several of the other targeted species have declined in the second-growth oak-hickory forested habitat. Specifically, within suitable and preferred habitat, shifts in habitat occupancy have occurred due to various, and not unexpected phenomena, including natural succession, during the 27 years of the project. Notable, however, is that during the past five years several aggressive invasive plant species have rapidly changed certain sub-areas, but not all, of the 2000 ha study site. Because of the large overall size of the study area, and because the variable rate of encroachment throughout the study area, it was possible to test the effect of invasives using several non-parametric statistics. The most rapidly advancing plants and also apparently the species of most negative consequence are Tree of Heaven (Ailanthus altissima [Mill.] Swingle, [Simaroubaceae]) and Mile-A-Minute Weed (Polygonum perfoliatum [L.] [Polygonaceae]). To a lesser extent, forest bird habitat at this research site has been degraded by the encroachment of Wineberry (Rubus phoenicolasius [Maxim] [Rosaceae]), Russian-Olive (Elaeagnus angustifolia L. [Elaeagnaceae]), and Japanese Barberry (Berberis thunbergii [Berberidaceae]). Two tree species, Black locust (Robinia pseudoacacia) and Princess Tree (Paulownia tomentosa), considered to be invasive, have indeed increased significantly within the core areas of the birds' habitat, but the encroachment of these plants does not appear to have deterred the expected bird occupancy or their nesting success. Overall, invasive plants encroachment into oak-hickory second-growth forest bird habitat at this north-central Virginia site, and its effect on bird occupancy and nesting success is probably typical of mid-Atlantic piedmont and Appalachian forests.
ORGANOCHLORINE PESTICIDE CONTAMINATION IN RESIDENT NORTH AMERICAN PASSERINES
Cadwallader, A., Illinois Wesleyan University, Bloomington, IL, USA, firstname.lastname@example.org; Latman, K., Illinois Wesleyan University, Bloomington, IL, USA, email@example.com; Horvath, J., Illinois Wesleyan University, Bloomington, IL, USA, firstname.lastname@example.org; Capparella, A, P, Illinois State University, Normal, IL, USA, email@example.com; Frick, J, A, Illinois Wesleyan University, Bloomington, IL, USA, firstname.lastname@example.org; Harper, R, G, Illinois Wesleyan University, Bloomington, IL, USA, email@example.com
Organochlorine (OC) pesticide and metabolite levels were determined in resident North American passerines and woodpeckers obtained in Illinois from 1990-2004. Sixty-nine of 77 individual birds contained OC compounds above detection limits, including all eighteen species examined. Total contamination levels in individual birds ranged from 7.47 to 2,274.23 ng/g (ppb). The most prevalent OC compound was p,p�-DDE, which was present in 45 birds across 15 species; dieldrin was found in 30 birds across 13 species, heptachlor and heptachlor epoxide were each found in 27 birds across 8 and 10 species, respectively, and p,p�-DDT was found in 25 birds across 13 species. There was no significant difference in total OC levels between males and females, between HY and AHY birds, and there was no significant effect of latitude. There was a significant difference in total OC levels between diet categories as omnivores had significantly higher total OC levels than granivores. House sparrows had significantly lower total OC levels than both white-throated sparrows and American robins.
AN UNPAVED ROAD AFFECTS THE DISTRIBUTION, REPRODUCTION, AND PHYSIOLOGICAL STRESS RESPONSE IN A MIGRATORY LANDBIRD
Dietz, M, S, University of Michigan, Ann Arbor, USA,
Murdock, C., University of Michigan, Ann Arbor, USA,
Romero, L, M, Tufts University, Medford, USA,
Foufopoulos, J., University of Michigan, Ann Arbor, USA,
Studies of road effects on birds often have not considered demographic measures or mechanisms. I investigated the effects of an unpaved Forest Service road on the distribution, reproduction, and stress physiology of White-crowned Sparrows (Zonotrichia leucophrys oriantha) in Colorado. I found and monitored 152 nests over three years and captured 123 individuals over two years for standardized stress series experiments. I found that the road has a substantial impact on reproductive success (p < 0.001) primarily due to high rates of roadside desertion of nests. The probability of a nest succeeding increased as distance to road increased up to 40 m, but nests beyond 40 m experienced lower nest success, possibly due to an increase in the diversity of predators near the habitat edge. I also found that the magnitude of the stress response of male sparrows subjected to an experimental stressor was related to distance to the road (p = 0.01) and corresponded inversely to sparrow nest success at those distances. My study is the first to document the effects of roads on blood corticosterone levels -- a stress hormone -- in any bird species, and the first to investigate nest success in relation to roads in the western United States.
THE EFFECTS OF MERCURY CONTAMINATION ON THE NESTING SUCCESS OF TREE SWALLOWS (TACHYCINETA BICOLOR)
Brasso, R, L, The College of William and Mary, Williamsburg, USA, firstname.lastname@example.org; Jefferson-George, R., The College of William and Mary, Williamsburg, USA, Cristol, D, A, The College of William and Mary, Williamsburg, USA, email@example.com
Mercury released from an industrial source into the South River between 1929
and 1950 has contaminated this tributary of the Shenandoah River. We chose tree
swallows (Tachycineta bicolor) as bioindicators because they forage on flying
insects with aquatic larval stages and so might be a likely non-piscivorous
route for mercury entering the food chain. In February 2005, 200 nest boxes were
placed along the South, Middle, North, and South Fork Shenandoah Rivers. Half of
the nest boxes were placed along contaminated portions of the watershed, the
other half on uncontaminated reference tributaries. Samples of blood and
feathers were taken from breeding adults and nestlings to determine mercury
levels. All nests were assessed for basic reproductive parameters including
first egg date, clutch size, number of eggs hatched, and nestling survivorship
to fledging. There was a significant difference in mercury levels between the
adults nesting in the contaminated and reference areas. However, we detected few
differences in nesting success between the two groups. There was no apparent
correlation between a female's blood mercury level and her nesting success.
Current study is addressing whether exposure to mercury on the breeding grounds
in 2005 impacted the survival of tree swallows through migration and winter into
INVASIVE TAMARISKS MAKE BETTER NEST SITES FOR PHAINOPEPLAS (PHAINOPEPLA NITENS) THAN DO NATIVE MESQUITES IN MIXED SPECIES BOSQUES
CRAMPTON, L, H, UNIVERSITY OF NEVADA RENO, RENO, United States, CRAMPTON@UNR.NEVADA.EDU; MURPHY, D, D, UNIVERSITY OF NEVADA RENO, RENO, United States, DDMURPHY@BIODIVERSITY.UNR.EDU
As tamarisk invades riparian areas and replaces native species, its contribution to avian habitat is debated. Although tamarisk's habitat value may be inferior to that of native species, it may be better than a complete absence of trees, thus essential for conservation of riparian species of concern. We show that when tamarisk codominates in riparian bosques, it provides better nesting habitat for Phainopeplas, a species of concern in Nevada, USA, than does native mesquite. While Phainopeplas are absent from tamarisk-dominated bosques, they reach high densities in mixed tamarisk-mesquite bosques (3.9 birds/ha vs 1.1 birds/ha in mesquite bosques). Overall nest success (from Program MARK) is similar in mixed and native bosques (~60%), but in mixed bosques, Phainopepla nests in tamarisks are more successful (90%, n=10) than those in mesquites (37%, n=11). Phainopepla nest selection and success are positively correlated with tree height, tree density, vegetative cover and berry abundance (best-supported models in Program MARK and Logistic Regression). Tamarisks are better nest sites than mesquites, despite lacking berries, because on average they are taller (4.2 vs 3.8m), and their nearest mesquite neighbors are more numerous (2.92 vs 1.83 trees/0.04ha), closer (14.9 vs 15.7 m) and have more berries (2437 vs 1518) (stepwise logistic regression, X2=16.3, df=6, p < 0.05). This study suggests that while tamarisk should be prevented from establishing local monocultures, riparian restoration perhaps should incrementally replace pockets of tamarisk, not remove it wholesale.
THE RESPONSE OF MIGRANT LANDBIRDS TO TAMARIX INVASION IN RIPARIAN AREAS IS INFLUENCED BY FLORISTICS AND PHYSIOGNOMY
Walker, H, A, USDA Forest Service Rocky Mountain Research Station, Albuquerque, USA, firstname.lastname@example.org
To address whether the response of migrating landbirds to exotic Tamarix (tamarisk: saltcedar) invasion in riparian areas is dependent on plant species composition (floristics) and vegetation structure (physiognomy), mist netting and vegetation surveys were completed during the fall migrations of 1999 through 2002 within twenty-four study sites varying in floristics (from 100% native to 100% exotic) and physiognomy along the middle Rio Grande, New Mexico. Nearly all of the measured avian community variables were significantly correlated with both floristics and physiognomy, likely due to floristic influence on the composition and the timing of availability of arthropod prey, and physiognomic influence on the number and types of horizontal and vertical microhabitats. After controlling for covariance between floristics and physiognomy, avian species composition and abundances were equally associated with floristics and physiognomy, while avian species richness was more strongly correlated with physiognomy. For those management efforts seeking to control tamarisk while protecting both migrant landbirds and their stopover habitats, results from this research indicate that structurally homogenous, monocultures of tamarisk should be a priority for removal, while removal of horizontally and vertically complex stands of tamarisk that contain some attendant native plant species should be deferred until some native vegetation has been restored.
AVIAN DIVERSITY AND PREVALENCE OF WEST NILE VIRUS INFECTION IN THE CHICAGO, ILLINOIS, EPICENTER
Loss, S, R, University of Illinois, Urbana-Champaign, USA, email@example.comBrawn, J, D, University of Illinois, Urbana-Champaign, USA, firstname.lastname@example.org; Hamer, G, L, Michigan State University, East Lansing, USA, email@example.comWalker, E, D, Michigan State University, East Lansing, USA, firstname.lastname@example.org; Ruiz, M, O, University of Illinois, Urbana-Champaign, USA, email@example.com; Goldberg, T, L, University of Illinois, Urbana-Champaign, USA, firstname.lastname@example.org; Schotthoefer, A, M, University of Illinois, Urbana-Champaign, USA, email@example.com; Kitron, U, D, University of Illinois, Urbana-Champaign, USA, firstname.lastname@example.org; Smith, R, J, University of Illinois, Urbana-Champaign, USA, email@example.com; Brown, W, M, University of Illinois, Urbana-Champaign, USA, firstname.lastname@example.org
West Nile virus (WNV) has emerged as one of the most dominant vector borne diseases in North America since its initial U.S. introduction. Birds are fundamental to WNV transmission as reservoirs and amplifying hosts in the virus life cycle. Understanding host diversity is necessary for determining patterns of occurrence of vector borne diseases at coarse spatial scales. The dilution effect of host diversity is one process that appears to operate on regional scales, but its occurrence at local scales is uncertain. We related avian diversity to WNV bird seroprevalence in the Chicago area, Illinois, U.S.A., an area of historically high WNV activity. Preliminary results indicate variation in seroprevalence across host species, but show no clear association between species diversity and seroprevalence at local scales. Highly infected host species included Northern Cardinal, House Sparrow, and American Robin. Thus, our preliminary findings suggest that host diversity may not strongly affect WNV infection rate in birds at local scales; rather, species composition by highly infected bird species may be a determinant of WNV prevalence. Alternate hypotheses regarding mosquito vectors or environmental factors should also be considered. Continued sampling at a wider range of urban sites will clarify diversity-prevalence patterns at local scales.
RESPONSE OF BIRDS TO LANDSCAPE MATRIX IN FRAGMENTED FORESTS IN JAMAICA: DISPERSAL OR RESOURCE-LIMITATION?
Kennedy, C, M, University of Maryland, College Park, USA, email@example.com; Marra, P, , Smithsonian Migratory Bird Center, Washington, D.C., USA, firstname.lastname@example.org; Neel, M, , University of Maryland, College Park, USA, email@example.com; Fagan, W, , University of Maryland, College Park, USA, firstname.lastname@example.org
We examined how resident bird communities and different foraging guilds are affected by vegetation structure, patch area, patch isolation, and landscape context (i.e., matrix) in the wet limestone forests in Jamaica. Over 400 point counts were conducted within the forest and matrix of three types of fragmented landscapes -- agriculture, bauxite mining, and urban -- as well as intact forest. We found that communities within forested landscapes were significantly different than agriculture, bauxite, and urban (p<0.002); and agricultural patches were significantly different than urban (p<0.003) and bauxite (p<0.03). The variance in community composition was not strongly correlated with patch-level variables or within-patch vegetation, but rather by species abundance within the matrix. Nectarivores, ominivores and frugivores were least sensitive to forest fragmentation and actually thrived, particularly in urban areas, where they were abundant within the matrix. Insectivores were the most sensitive to forest fragmentation, with significantly lower abundances in urban and bauxite than agricultural and forested landscapes (p<0.01), and were largely absent within the matrix. All three fragmented landscapes displayed a significant richness-area relationship. Agricultural landscapes had the strongest richness relationship with patch size (R2: 0.71), as compared to bauxite (R2: 0.58), and urban (R2: 0.18). Urban landscapes exhibited the weakest species-area relationship, with the least amount of variance explained by patch area, attributed to the fact that urban areas provide additional resources (i.e., gardens) surrounding forest fragments as compared to agricultural and bauxite landscapes. In contrast, only bauxite landscapes displayed a significant richness-isolation relationship (p<0.01), thus, supporting that corridors in agricultural landscapes and garden plots in urban landscapes are potentially aiding dispersal among forest remnants.
PAINTED BUNTING CONSERVATION IN THE CAROLINAS: TRADITIONAL MONITORING MEETS CITIZEN SCIENCE
Rotenberg, J, A, University of North Carolina Wilmington, Wilmington, email@example.com; Barnhill, L, M, South Carolina Department of Natural Resources, Columbia, , firstname.lastname@example.org; Meyers, J, M, USGS Patuxent Wildlife Research Center and The University of Georgia, Athens, , email@example.com; Demarest, D, , US Fish and Wildlife Service, Atlanta, , firstname.lastname@example.org
Avian citizen science projects successfully focus on research and/or monitoring that are otherwise impossible to carryout by employing a few field technicians. Reliability of volunteer observations is high, with quality datasets used in many peer-reviewed publications. By using a citizen science approach, we initiated the Painted Bunting Monitoring Project, studying the eastern population of Painted Bunting (Passerina ciris) in North and South Carolina. BBS data shows that eastern Painted Buntings have declined at least 3.2% annually over a 30 year period, possibly due to increased coastal development and agricultural practices, both of which clear shrub-scrub brush vital to breeding Painted Buntings. Since Painted Buntings readily visit backyard bird feeders, citizens, acting as scientists, assist in a variety of data generating components to aid us in comparing subpopulations breeding in suburban vs. natural habitats. Along with backyard banding, these data include quantifying: demographic parameters such as population distribution, density and abundance; productivity and adult survival; and, behavioral patterns of site-fidelity and habitat use. Here we report our results from our Painted Bunting Observer Team volunteer (PBOTs) datasets. In addition to these data, our program resulted in an increase in public awareness for species conservation, contributing to environmental education and public outreach.
THE VALUE OF INSTALLING NEST BOXES FOR PEREGRINE FALCONS _FALCO PEREGRINUS MACROPUS_ IN AN URBANISED LANDSCAPE
Hurley, V, G, Deakin University, Burwood, Australia, email@example.com
During the 1970-80s Peregrine Falcons (Falco peregrinus macropus) in Victoria in SE Australia, were laying thinned shelled eggs at many nest sites (eyries). These coincided with the use of DDT at the time. Eggshell thinning across Victoria during these years reduced hatch rates to an average of 58.3%. Research elsewhere in Australia established that Peregrine egg hatch rates could also be influenced by the physical quality of a cliff eyrie. Quality here refers to the level of protection from rainfall and water run-off at the eyrie. In this current study we found Peregrine egg hatch rates in Victoria have now increased to an average of 83.4%. At 14 nest sites across Victoria nest boxes were installed at sites with especially low egg hatch rates. These eyries were in active quarries or urban buildings. The average egg hatch rate at these sites prior to the installation of nest boxes was 21.7%. Hatch rates increased to an average of 79.7% and egg clutch size also increased from 2.48 to 3.13 eggs per clutch with the adoption of nest boxes. We conclude that in recent years low egg hatch rates are due more to poor drainage and exposure at these eyries than impaired reproduction from chemical contaminants. http://www.unisolve.com.au/vpp/2005/contents.html
ROADWAY MORTALITY OF RAPTORS IN SOUTHERN IDAHO
Boves, T, J, Boise State University and the Raptor Research Center, Boise, USA, firstname.lastname@example.org; Belthoff, J, R, Boise State University and the Raptor Research Center, Boise, USA, JBELTHO@boisestate.edu
Especially in North America, we know little about what appears to be an increasingly serious wildlife conservation issue: mortality of raptors along highways. Roadway mortality is the leading cause of direct mortality of wildlife in North America. We are (1) quantifying raptor mortality along an interstate highway in s. Idaho, including portions that traverse the Snake River Birds of Prey National Conservation Area, and (2) gathering information on seasonal trends; species, ages, and sex classes involved; and cover types and geographic features within the adjacent areas of highways at locations where raptors are being killed. Beginning in July 2004, we surveyed a 250-km portion of Interstate 84 twice per month. This stretch of highway traverses grasslands, rangelands, and croplands. Surveys (n = 45 to date) located an average of 18.1 dead raptors per survey, representing 12 species. Barn Owls (Tyto alba) were the most frequent species found dead along the highway (n = 712, range = 2 - 103 per survey). Barn Owls seem to be most susceptible to roadway mortality because of attraction to agricultural areas along the roadway, their use of roadways during winter months, the proximity of roadways to nesting areas, or a combination of these reasons.
BIRDS AS MERCURY MONITORS FOR NORTH AMERICA
Evers, D, C, BioDiversity Research Institute, Gorham, United States, email@example.com; Murray, M, , National Wildlife Federation, Ann Arbor, United States; Wolfe, M, , California State University, Chico, United States; Zillioux, E, , Florida Power and Light, Juno Beach, United States; Bowerman, W, , Clemson University, Clemson, United States; Burger, J, , Rutgers University, Piscataway, United States; Atkeson, T, , Florida Dept. of Environmental Protection, Tallahassee, United States; Hames, R, , Cornell Lab of Ornithology, Ithaca, United States
The elevated level of anthropogenic mercury (Hg) in the environment is a long-term problem that requires coordinated solutions. Air emission sources are varied and releases can lead to transport that is local, regional, and global in nature. The need for reducing the level of environmental Hg input has been demonstrated for both human and ecological health purposes. Described here are birds that best meet a slate of criteria reflecting logistical, biological, social, and scientific attributes developed during a USEPA workshop in 2003. Several piscivorous and insectivorous birds were chosen based on a growing number of studies. Species that are of greatest concern for MeHg availability include those that are in sensitive habitats, are at the highest trophic levels, and are long-lived. Preliminary evidence indicates that multiple species of high conservation concern could be negatively impacted by elevated levels of environmental Hg in many areas of North America. A long-term monitoring program will provide an ability to monitor temporal trends as well as identify biological hotspots that may reflect high Hg deposition areas, habitats that are most sensitive to MeHg production and availability, and species that have behavioral, foraging, and demographic attributes that collectively create a high risk to MeHg bioaccumulation.
ACID RAIN, CALCIUM DEPLETION, AND MERCURY AS MULTIPLE STRESSORS OF FOREST-BREEDING TERRESTRIAL BIRDS IN NEW YORK
Hames, R, S, Cornell Laboratory of Ornithology, Ithaca, NY, United States, firstname.lastname@example.org; Lowe, J, D, Cornell Laboratory of Ornithology, Ithaca, NY, United States, email@example.com; Evers, D, C, BioDiversity Research Institute, Gorham, ME, United States, firstname.lastname@example.org; Rosenberg, K, V, Cornell Laboratory of Ornithology, Ithaca, NY, United States, email@example.com
Forest-breeding songbirds in northeastern North America are exposed to atmospheric deposition of acidifying ions and mercury, especially at higher elevations. Concomitant decreases in soil calcium pools and in abundance of calcium-rich invertebrates may make it difficult for insectivorous and granivorous birds to sequester sufficient calcium for laying a clutch of eggs and raising nestlings to fledging. In the presence of low dietary calcium, uptake of trace metals such as mercury is enhanced and these anthropogenic stressors in combination may have multiplicative, not additive, negative effects on bird populations. We report the results of a study of the effects of acid rain on soils and calcium-rich invertebrate abundance, as well as mercury contamination of soils, invertebrates, and birds of four common species at forty sites across New York. We show that soil pH and Cation Exchange Capacity (CEC), as well as calcium, zinc, and mercury content, varied widely by region, and that mercury content was significantly negatively correlated with pH and positively with CEC. We show that invertebrate abundance varied with pH and invertebrate mercury contamination varied with trophic level. Mercury contamination of birds varied between species and regions, and with soil properties. We discuss these results and future research.
ARSENIC RESIDUES IN BARK BEETLES AND WOODPECKERS OCCUPYING MOUNTAIN PINE BEETLE INFESTED STANDS TREATED WITH MSMA- EXPOSURE AND EFFECTS OF PESTICIDE TREATMENT
Morrissey, C, , Canadian Wildlife Services, Delta, Canada, firstname.lastname@example.org; Dods, P, , Canadian Wildlife Services, Delta, Canada; Albert, C, A, Simon Fraser University, Burnaby, Canada, email@example.com; Cullen, W, , University of British Columbia, Vancouver, Canada; Williams, T, , Simon Fraser University, Burnaby, Canada, firstname.lastname@example.org; Elliott, J, , Canadian Wildlife Services, Delta, Canada
The current Mountain Pine Beetle (MPB) epidemic has destroyed over 7 million ha of pine forest in British Columbia, Canada. An arsenic-based pesticide, monosodium methanearsonate (MSMA) has been used to suppress the beetle. We scored 597 reference and 558 MSMA trees for the amount of debarking, an index of woodpecker activity, almost 1 year after infestation. 40% of MSMA trees were debarked, but treated trees had significantly less debarking than untreated trees. Total arsenic in MPB from MSMA treated trees varied widely and the organic metabolite MMAA contributed over 90% to the total arsenic extracted. MPBs from reference trees had lower concentrations that averaged two hundredths of MSMA trees. Focal observations and point counts confirmed several species of woodpeckers regularly used MSMA stands while breeding. Analysis of blood from woodpeckers and other forest birds breeding near MSMA treatments further showed elevated blood arsenic levels. MSMA strongly reduced the emergence of several bark beetle species including the MPB, and there was a highly significant positive relationship between Dendroctonus beetles and Three-toed woodpecker abundance. This study identifies the potential negative impact that use of pesticides for bark beetle suppression can have on woodpecker populations that rely on the beetles and their host trees.
BIOENERGETICS-BASED MODEL FOR THE ACCUMULATION OF ORGANOCHLORINE POLLUTANTS BY TREE SWALLOW NESTLINGS
Sebastian, M, , University of Windsor, Windsor, email@example.com; Ciborowski, J, H, University of Windsor, Windsor, , firstname.lastname@example.org
Our research investigates the biomagnification of organochlorine pollutants by nestlings of insectivorous birds. This work uses bioenergetics principles and type of food consumed to validate bioenergetics based models. Tree swallows are migratory passerines that breed in Point Pelee National Park. They are aerial insectivores that feed mainly on the adults of recently emerged aquatic insects. They feed their nestlings with locally available insects. Insects are affected by environmental contaminants and they in turn transfer the contaminants to their consumers. The developmental history and habitats of insect larvae greatly influence the types of contaminants accumulated and passed on to predators. So, depending on the fraction of aquatic and terrestrial insects consumed, nestlings accumulate different types and amounts of contaminants. The feeding strategy of organisms is an important component to consider when studying contaminant biomagnification, especially in terrestrial organisms. Insectivorous passerine nestlings are good indicators of contaminant biomagnification from their immediate surroundings. We measured nestling body weight, dietary composition, and contaminant content of insects from Point Pelee National Park in 2002 and 2003. Other model parameters are derived from previous studies of tree swallows. The bioenergetics model provided a good fit to observed growth data and contaminant bioaccumulation for swallow nestlings.