Willet migration, new research

This video from the USA is called Marbled Godwit and Willets.

By Darci Palmquist in the USA:

Secrets of Willet Migration Revealed

August 7th, 2012

Olympic athletes are impressive, no doubt. But when it comes to athletic prowess, few creatures compare to migratory birds like the eastern willet.

A large shorebird with distinctive white racing stripes and a unique penchant for nesting in salt marshes, the willet flies at speeds up to 57 MPH to cross the Atlantic Ocean in just 3 days. Leaving its nesting grounds at the Delaware Bayshores by early August, willets cover some 3,500 miles before eventually settling down for the winter in … where?

The secret location of willets’ wintering grounds had been a mystery—until now. Conservancy ecologist Joe Smith studied willet migration for the past 3 years and discovered that the eastern willet winters in estuaries on the northern coast of South America, mostly in Brazil and Suriname.

His discovery comes with the aid of new geolocator tags that rely on hours of sunlight to pinpoint latitude and longitude. Geolocators are lightweight, small and cheap—allowing scientists to track more types of birds, like willets, that were considered too small for the bulkier satellite tags traditionally used.

Such advances in technology are ushering in a new era of bird studies and giving scientists deeper insight into the full annual life cycle of migratory animals, a burgeoning field known as “migratory connectivity.” It goes beyond discovering where birds like willets winter to answering more complicated questions about how they migrate—such as how many miles they travel per day and how many places they stop. Migratory connectivity even uses advanced analysis of birds’ chemical makeup to understand what the habitat conditions are like at their wintering grounds.

“It’s a golden age for tracking migration,” enthuses Smith. “We’re learning that it’s a big world, yet it’s a small world for these birds because they use very discrete places.”

And these advances in science can mean better conservation for birds like the willet.

(See a photo slideshow of Smith catching willets as part of his research.)

An Overlooked Species of Scientific Research

Very few studies have been conducted on eastern willets, with only one significant research project in the 1970s. Smith’s study will provide the richest collection of data about the migration of this species to date.

In addition to the geolocator tags, Smith’s team collects feather and blood samples that are then analyzed for mercury and carbon and nitrogen isotopes by experts at the Biodiversity Research Institute (BRI) and Smithsonian Migratory Bird Center. Together they’re piecing together a more complete picture of the annual life cycle of an eastern willet.

The birds’ primary wintering area in Brazil happens to be a shorebird hotspot—it has the largest tract of intact mangrove forest in the Western Hemisphere and is sparsely populated. It’s not a big surprise that the willets spend their winter here, where the mangroves are lush and the food is plentiful.

What is a surprise is the other discovery that Smith’s team has made: willets are picking up mercury pollution at potentially harmful levels at these seemingly pristine wintering grounds.

“We know this because of the feather samples,” explains Smith. “Feathers retain a signature of the habitat conditions where they were grown. When the birds arrive here to nest, we can get a really good sense of what their winter habitat conditions were like from feather samples.”