— Excerpt from Wiliam Vogt’s 1937 paper, Preliminary notes on the behavior and ecology of the eastern willet.
It’s been almost 80 years since Vogt shared his observations of willets at Fortescue, New Jersey, but the quest continues to outwit and understand these birds.
I have been working with the Smithsonian Migratory Bird Center, Biodiversity Research Institute, Biodiversity Works and the Gulf Coast Bird Observatory to use migration tracking tags to increase our understanding of the willet’s year-round cycle.
The outwitting part remains vital because we need to capture the birds once to deploy the tags — and capture them again, one year later, to recover the data the tags recorded.
Having recovered 31 of these geolocator tags so far, one of our key discoveries is the high level of migratory connectivity between east coast nesting areas in North America with nonbreeding areas on the coast of northern South America.
Although we knew the winter distribution of willets in general, the job of sorting where the two subspecies (eastern and western) spend the winter still needs much refinement.
We’ve refined one part of this winter range by tracking the majority of our willets from New Jersey, Massachusetts and Maine to a single stretch of coastline in northern Brazil.
This isn’t just any old chunk of coast — it is the largest contiguous tract of mangroves in the world.
This stretch of coast is a critical wintering site for not just willets, but also for other shorebirds such as red knots and whimbrels.
Beyond our geolocator tracking data, data from old-fashioned band recoveries tell a similar tale. Band recoveries happen when someone catches or kills a bird with a numbered leg band. The person who recovers the band then reports the number to the appropriate agency. In the case of eastern willets, birds were banded in the U.S. and Canada on their nesting grounds and all recoveries occurred in northern South America.
There has never been a winter recovery of banded willet anywhere else. This additional migratory connectivity information suggest that northern South America could be the only place that eastern willets winter. The map below shows recoveries of willets in South America that were banded at salt marsh breeding sites in Eastern North America, from Georgia to Nova Scotia.
One more bit of evidence that northern South America is the place for wintering Eastern willets is the map below. It depicts counts of willets during surveys of the entire South American coastline. The orange dots indicate southbound stopover sites of our geolocator-tracked willets and the blue dots indicate wintering sites.
MORE ON THE WILLET PROJECT
At The Nature Conservancy:
Secrets of Willet Migration Revealed
A 3-year research project is helping to lift the veil on migration
To Catch a Willet
New technology is transforming the study of migratory birds
In Birdwatching Magazine, April 2013 Issue: