Tracking "Chatham": Understanding How Young Shorebirds Find Their Way

By Brad Winn, Director, Shorebird Habitat Management

 

During World Shorebirds Day last year, Brad Winn, Director of Manomet’s Shorebird Habitat Management Division, and partners from the Georgia Department of Natural Resources tagged a juvenile Whimbrel on Cape Cod with a 5-gram solar-powered tracking device, representing the first “hatch-year” Whimbrel ever fitted with satellite transmitter technology.

 

 

 

The Whimbrel, aptly named Chatham, was captured in a saltmarsh on the outer edge of Cape Cod near the town of Chatham, across from Monomoy National Wildlife Refuge. While it has been known that Whimbrels use the beaches and marshes of Cape Cod in late summer and early fall, their daily movements to feed on fiddler crabs in the marshes, and the locations of nighttime roosting sites have been a mystery. Chatham helped reveal those secrets before she launched south as the sun set on September 26 after a brief stopover on Nantucket Island.

 

Another important aspect of this research is to understand how young Whimbrels like Chatham make their way down to the tropics for their first migration, and select wintering habitats they will return to every year of their lives. While the adult Whimbrels that have been tracked during the last seven years have exhibited high levels of site fidelity—flying direct point to point flights between nesting, staging, and wintering sites—the behavior of a first-time migrant is totally unknown.

 

Chatham was just an egg in June 2015, so it is amazing to think, that after feeding heavily on fiddler crabs throughout Mill Creek Marsh during late August and September, this young Whimbrel flew non-stop for 60 hours over 1,759 miles of open ocean to land in the British Virgin Islands. Chatham has been island hopping since she first touched down on Anegada. She has spent time on six different islands, including Eustacia, Prickly Pear, Virgin Gorda, Anguilla, and Dog Island (bird sanctuary), and has retraced her flights back to Anegada where she has spent most of the winter, spring and summer. She is expected to fly north again in April of 2017 in her third year. We believe that she is from the Hudson Bay Lowlands of Nunavut, Canada, but she could surprise us and go all the way across Canada to the Mackenzie River Delta to breed for the first time.

 

Tracking Chatham is helping us understand how naïve birds learn their landscapes. Understanding the needs of shorebirds by tracking them through their migrations over several years has helped the conservation community to learn where there might be threats to shorebird populations, and guide our work with partners internationally to address the threats impacting them.

 

This work has been funded by the Emily “Paddy” V. Wade Fellowship for Science.