Most populations of migratory birds are now threatened. It is estimated that the populations of 1 out of every 2 songbirds are declining in the Western Hemisphere with impacts predicted to worsen with climate change. However, because migratory birds have both breeding and wintering areas and may move vast distances between them, understanding where the steepest population declines are occurring has been difficult or impossible. To address this critical issue, researchers at the Center for Tropical Research recently launched the Bird Genoscape Project, an effort to map the population-specific migratory routes of 100 species of migratory songbirds by harnessing the power of genomics. Identifying these migratory connections provides an effective tool for monitoring declining populations and for developing effective conservation strategies.
What is a Genoscape?
A genoscape is a map of genetic variation across the geographic range of a species. Once a genoscape has been created, it can be used to trace the breeding origin of a bird captured anywhere along its migratory pathway using DNA contained within a single feather.
How does it work?
The first step towards determining the population-specific migration routes involves building a Genoscape, or a map of genetic variation across geographic space. By harnessing recent advances in next-generation sequencing, we can scan the genomes of these birds and identify base pairs that are unique to a particular population.
For example, in the Wilson’s warbler, this analysis helped identify six genetically distinct groups: Alaska to Alberta (purple), eastern North America (red), the Southern Rockies and Colorado Plateau (orange), the Pacific Northwest (green), Sierra Nevada (pink) and Coastal California (yellow; Fig. 1B). Using DNA from feather samples collected during migration, we were then able to trace migrants back to their breeding origin, and hence determine population-specific migratory routes. Compared to the existing species-wide range maps (Fig 1A), genoscapes provide more detail about population specific ranges and migratory routes (Fig 1B).
Read more about the Wilson’s warbler Genoscape Project here.
Vision: The Next 100 Species
We are working with many governmental and non-profit partners to expand the development of high-resolution molecular tags to species and populations of conservation concern across the Western Hemisphere. The goal is to build genoscapes for 100 species of migratory birds, 50 of which will be built by 2020. The resulting information will provide an excellent tool for monitoring declining populations of migratory species in the face of global climate change and other anthropogenic stressors.
We are currently developing genoscapes for Yelllow Warblers, Willow Flycatchers, Swainson’s Thrushes, Common Yellowthroats, American Kestrels, Painted Buntings, Burrowing Owls and Tricolored Blackbirds. Over the next few years, we will expand the project to include many more species of concern.
Highlighted species: American Kestrel
Although American Kestrels are a common and widespread species, their populations have been declining since the 1970s. Determining the source of this decline, however, has been tricky because little is known about where they go when they migrate. The Bird Genoscape Project will help identify wintering range and migration routes for specific breeding populations, which will provide crucial information that will aid in conservation efforts.
Listen to podcasts and watch videos about the American Kestrel Genoscape Project here.
The Bird Genoscape Project is a highly collaborative, multi-year project that relies on the participation and contribution of bird biologists all over the Western Hemisphere. If you work with one or more of our target taxa and would like to contribute blood, feather or DNA samples to the project, please email Dr. Thomas Smith (firstname.lastname@example.org) or Dr. Kristen Ruegg (email@example.com).
The following links provide more information about The Bird Genoscape Project:
News article: Hidden Bird Migrations Revealed by DNA
Webinar by Kristen Ruegg: High Resolution Molecular Tags for Tracking Migratory Birds