For over a decade, volunteer bird banding station operators in North America have donated their time and expertise to collect feather samples to enhance and expand the Neotropical Migratory Bird Conservation Genetics Project. This project, which originated at the Center for Tropical Research at San Francisco State University, was moved to UCLA in 2002 and is currently housed at UCLA’s Conservation Genetics Resource Center (CGRC). CGRC is managed by the Center for Tropical Research (CTR) and the UCLA Department of Ecology and Evolutionary Biology.
The feather sampling efforts have resulted in a rapidly growing collection of approximately 60,000 feathers, which will expand by 15-20 thousand feathers per year for the next four years. This expansion is due in large part to the operators participating in the UCLA/Institute for Bird Populations (IBP) and UCLA/Landbird Monitoring Network of the Americas (LaMNA) avian influenza sampling efforts. The UCLA Conservation Genetics Resource Center feather collection is a unique and incredibly useful resource for researchers interested in population genetics, migratory connectivity, and disease ecology. Several published and ongoing studies have made use of this collection. The following is a summary of projects that have taken advantage of the feather collection and that have benefited from the generous contributions of bird banding station operators and banding networks.
Past and Current Projects Utilizing the UCLA Conservation Genetics Resource Center Feather Collection
West Nile Virus Infection in North American Migratory Birds
UCLA researcher Ryan Harrigan is using the feather collection to examine the ecological correlates of West Nile virus (WNV) infection in migratory birds. This research is aimed towards determining: 1) how disease hotspots vary with climate and ecological change, and 2) whether WNV can be detected in birds that were previously infected but have since recovered from the disease. WNV RNA can be extracted from a feather calamus of previously exposed individuals. WNV can then be genetically detected using a technique called real time RT-PCR (reverse transcription-polymerase chain reaction). To date, Ryan has detected WNV in feathers of several American Crows (Corvus brachyrhynchos) that were known to have died from the disease. In addition, WNV was detected in American Robins (Turdus migratorius) from Georgia, Texas, and New Jersey that were suspected of carrying the infection. For more information on Ryan's research, please click here.
Population Biology and Ecology of Corvidae in California
Holly Ernest, Associate Director of the wildlife and Ecology Unit in the Veterinary Genetics Laboratory at the University of California, Davis, was provided feather collection samples to study the ecology and population biology of Corvidae in California. She received feather samples that were collected from two species of Corvidae native to California: the Western Scrub Jay (Aphelocoma californica) and Steller’s Jay (Cyanocitta stelleri). Holly and her team of researchers are examining genetic markers (including microsatellites and mitochondrial DNA [mtDNA]) in a variety of Corvidae species in addition to the two mentioned above. For more information about Holly's work, please click here.
Range Expansion and Lineage Diversification in the Genus Junco
CTR researchers Borja Milá, John McCormack, and Gabriela Castañeda used feather collection samples to study the range expansion and lineage diversification in Juncos. They were interested in the role that Pleistocene glacial cycles play in the diversification in North American temperate and boreal bird species. It is generally assumed that the diversification seen today between sister taxa is the result of the long-term isolation of populations in glacial refugia over glacial cycles. Alternatively, it is hypothesized that that rapid postglacial range expansion and recolonization of northern latitudes following glacial maxima could account for speciation events. The researchers used genetic variation (mtDNA and amplified fragment length polymorphism [AFLP]) data to understand the mechanism of Junco diversification in North America. They discovered that the genus underwent a rapid diversification as a result of a range expansion event that occurred within the last 10,000 years. The genetic data shows that the Yellow-eyed Junco of Mesoamerica expanded northward at the end of the last glacial maximum and speciated into the Dark-eyed Junco. This species then diversified into at least five distinct and geographically structured morphotypes which are found today in the U.S. and Canada. For more information about this research, click on the following links: Borja Mila, John McCormack.
The Migratory Divide in the Hermit Thrush
UCLA researcher Allison Alvarado is using Hermit Thrush (Catharus guttatus) feathers from the CGRC feather collection to identify the mechanisms responsible for creating and maintaining a migratory divide between different populations of Hermit Thrush. A migratory divide is a situation in which neighboring breeding populations of the same species follow different migratory routes to overwintering areas. The current hypothesis for why neighboring populations do not migrate together is that different migratory behaviors are the result of divergence between eastern and western populations that were isolated in geographically separate glacial refugia. After the last glacial maximum, both eastern and western populations expanded their geographic ranges north into the Pacific Northwest to where they now come into contact. Preliminary genetic analysis of the feathers supports this hypothesis. Continuing research is aimed at identifying the exact location of the contact zone and assessing the extent to which eastern and western populations interbreed. For more information about Allison's research, please click here.
Migratory Patterns and Population Connectivity in Wilson’s Warbler
Several researchers are conducting migratory connectivity research on Wilson’s warbler using samples from the feather collection, using genetic and/or stable isotope methods.
CTR researchers Sonya Clegg (Imperial College, London) Jeffrey Kelly (Oklahoma University), and Mari Kimura (Cornell University) used feathers from the collection to study population connectivity and migration patterns in Wilson’s Warbler (Wilsonia pusilla). These researchers used genetic markers (microsatellite DNA variation) and hydrogen stable isotope analysis to identify the migratory routes that connect populations of Wilson’s Warbler to wintering areas in Mexico and Central America and breeding grounds in Canada and the northern U.S. Genetic data indicated population structure across the North American continent; microsatellite markers of western birds were found to be significantly different than those of eastern birds. Isotope analysis revealed a migration pattern in which genetically identified western birds that breed at the most northern latitudes overwintered at the most southerly latitudes in Central America. This is consistent with the "leap-frog" pattern of migration. In addition, coastal-breeding birds overwintered in western Mexico, whereas inland-breeding birds overwintered in eastern Mexico. To read the article on this reasearch, please click here, or click on the following links for more information on the past and present work of these researchers: Sonya Clegg, Jeffrey F. Kelly, Mari Kimura.
Northern Arizona University researcher Kristin Paxton and her colleagues studied spatial and temporal patterns of Wilson’s Warbler migration. The goal of this research was to understand long-term population trends in this migratory bird by linking migration period to other stages of the annual cycle and the degree of population segregation in both time and space. Stable hydrogen isotope (dD) analysis was used to identify the breeding locations of migrants passing through five sites spanning a cross-section of the species’ southwestern migration route during the spring of 2003 and 2004. The researchers found a negative relationship between the date Wilson’s Warblers passed through the sampling station and dD values of their feathers. This data agree with an earlier hypothesis (see the work above) that this species follows a “leap-frog” migration pattern. They showed that this pattern was consistent across sites for multiple years. In addition, the mean dD values became more negative across sampling stations from west to east, with the mean dD values at each station corresponding to different geographic regions of the Wilson’s Warbler's western breeding range. This means that Wilson’s Warblers passing through a station are region-specific, with birds from western breeding regions traveling through farther west migration stations, and more eastern breeding birds traveling through the farther eastern migration stations. This indicates that habitat alterations for specific areas across the east–west expanse of the birds' migratory route in the southwestern U.S. could unequally affect different regional breeding populations of Wilson’s Warblers. This study shows that information on migration patterns of Neotropical migrants can prove critical for the management of breeding populations of these birds. For more information about this research, please click here.
University of British Columbia researcher Darrin Irwin, in collaboration with CTR, is making use of the CGRC feather collection to study migratory connectivity in Wilson’s Warbler via genetic variation. The feathers are being used to survey the genetic variation within this species across both its breeding (Canada and the U.S.) and wintering (Mexico and Central America) areas. This genetic variation will be used to link individuals to specific breeding and wintering grounds. This information can be used to: 1) study the ecology and evolution of these birds, and 2) develop conservation strategies for the long-term survival of the species. In addition, this data will also be used to elucidate the relationship between avian influenza virus (AIV) and migratory connectivity. For more information about Darrin's research, please click here.