One of the best parts of my job as director of The Nature Conservancy’s migratory bird program is reading the reports that come in from the research we sponsor — especially on birds about whose wintering habits we previously knew little.
I recently received the final report of the field research being conducted by my colleague Gabriel Colorado, a Colombian ornithologist now working on his Ph.D. at The Ohio State University. Gabriel is studying the wintering ground ecology of the Cerulean Warbler in Colombia, the heart of its wintering range in the Andes Mountains of South America. The Spanish name for the warbler is “Reinita Cielo Azul,” which, roughly translated, is my title for this post.
The Cerulean Warbler is the subject of research since it is one of the fastest declining songbirds found in the eastern deciduous forests of North America and is on the WatchList compiled by American Bird Conservancy and National Audubon Society. It is almost unique among North American migratory birds because it winters exclusively in South America from Venezuela to Peru (it used to occur as far south as Bolivia, but we have found no recent sightings there). As with many other migratory birds, little is known of its ecology, habitat preferences, diet, and behavior in the winter — the Conservancy’s Migratory Bird Program has been actively working to address these information gaps, including sponsoring Gabriel’s research.
This research is so exciting that every time I read the reports, I immediately want to head to the field to help out. Gabriel and his team have, since 2003, captured 49 individual Cerulean Warblers. They have used an innovative technique with aerial mist nets suspended on bamboo poles high in the canopy, which is what you have to do to capture this species. Most incredible, the team has recaptured 4 of these birds in different wintering seasons.
This has demonstrated, I believe for the first time, that some individual Cerulean Warblers return to the same wintering area in succeeding years — something we’ve always suspected, but have never proven. So you can meet some of the characters, on the left is a photo of a female Cerulean named Aleja, who was caught and banded in March, 2009. You can see some of the color bands that were placed on her, so she could be followed to study her behavior and diet.
Gabriel’s research efforts have also taken him, over the years, to Venezuela, Ecuador, and Peru. The latter country provided some unique challenges for the field team, including really bad roads, rivers that had to be crossed with a rolling carriage on cables (see left), and inaccessible terrain. A far greater challenge, however, was that after securing permission from community leaders to work in a remote area, unfounded rumors began to circulate which meant that the team had to abruptly leave the area! Despite these issues, the team has gathered large quantities of very valuable data and made very useful contacts for future work.