Swainson’s Warbler migratory connectivity

Collaborators: Erik Johnson, Katie Percy, Garrett Rhyne, Phil Stouffer, Alicia Brunner, Bryant Dossman, Pete Marra, et al.

Swainson’s Warblers are among the least-known of North American warblers, partly because they inhabit thick forest with difficult access, where they lead secluded lives in the shady understory—at least on the breeding grounds. Their wintering grounds include parts of Central America and the Caribbean, but little is known about which birds go where, how and when they get there, etc.

To answer some of these basic questions, I put some money together with Louisiana Audubon to buy 10 light-level geolocators, which at this time constitute the best option to track birds < 20 g (SWWAs are ~ 15 g). We deployed geos on birds at three sites around Louisiana in 2018 and recovered five the following year. At that point we were contacted by folks from the Smithsonian, who were independently tagging SWWAs in Jamaica and had comparable bird numbers and timeline. We decided to join the two projects and are currently writing the results up for publication.

Garrett Rhyne, the newest member of the Stouffer Lab, is now developing a much more comprehensive study of SWWA migratory connectivity. Several collaborators will deploy dozens of geos across the breeding range. Within the next several years, our knowledge of which birds winter where should be much improved.