Anyone who regularly reads our newsletter, blog, or attends our programs knows that Audubon North Carolina has spent a lot of time and effort over the last few years working to learn about and conserve Golden-winged Warblers (GWWA). And we are not alone. The Golden-winged Warbler Working Group (GWWAWG)was established in 2005, by more than 75 partners, to dig deep into the science and life cycle of this species. In this series of blog posts, learn about all the work of the GWWWG and what this collaborative effort has done to protect this tiny gem of our forests.
Post by Curtis Smalling, Coordinator NC IBA Program & Mountain Program Manager
We are on the cusp of having some geo-locators small enough to use on Golden-wings, but are probably one to two years away from that. (See our story on Wood Thrush geo-locators at our same study site in Nicaragua).
But other methods exist and are starting to be used. The most promising of those methods is what is known as stable isotope analysis. This method uses trace isotopes of certain elements that correspond to certain geologies and locations. Some of these are remarkably precise in the ability to map where the element was absorbed into the bird. The most common thing to use for this work is feathers. Most birds molt their feathers at least once per year, and many do this both on the breeding and wintering grounds.
A recent analysis of a sample of feathers collected from the wintering grounds suggests a basic slip southward for Golden-wings. This means that birds from the northern part of the breeding range winter the farthest north (Honduras, Nicaragua), and the birds farther south slip father south into northern South America. From this we’ve determined our birds likely winter in Colombia, but more study is needed to confirm this– exciting stuff as we start to figure out some of the limiting factors on the wintering grounds, as well as what we can do on the breeding grounds to conserve the species!
In fact, I just returned from a trip to Salt Lake City for the fifth international Partners in Flight conference meeting, at which we started writing conservation plans for wintering grounds conservation projects across the region. And by no surprise, I have been working on the highlands regions of Central and South America where Golden-wings winter. The primary goal is forest protection, just as it is on the breeding grounds. As an example, if our birds winter in Colombia, that country has only 7 percent of its historical montane forest remaining. This could explain a lot of the declines we have seen here on the breeding grounds if birds are not finding sufficient winter habitat to survive and return.