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Studying Migratory Shorebirds, Researchers Zero In on the Wily Willet

Courtesy photo

Migratory birds historically have been difficult for scientists to study. Where they go, how they get there and how long it takes them have been mysteries for many species including the willet, a shorebird that nests along the Atlantic Coast.

Now, new technology is allowing scientist to track the birds -- but first, they need to catch them.

Liz Baldwin is standing with a clipboard at the edge of Fuller Street Beach, using her pen to sketch the beach’s terrain, and the possible pathways to catch willets. Catching willets requires careful planning. So it’s a good idea to have multiple strategies and tools. Although petite in size, she said these birds are very smart and territorial.

“So this is a mist net," Baldwin said. "It is a very long mist net because ideally, the willet stay on the nest for the last possible second. So having a really long mist net on two big bamboo poles we can get over the net without the bird even knowing that we are there.”

After instruction the team walks stealthily through the seagrass, and in a planned motion they drop the net on a nest. The female willet escapes in time before the net lands. That gives the team time to analyze the unhatched eggs to see if predators, like skunks or crows have eaten them.

“This is probably one of our birds," said Luianne Johnson, the director of Biodiversity Works MV team and Baldwin's assistant. "See how fast they move? These guys are built for speed. So if you see them fly versus an oystercatcher its way different. These guys move like fighter jets.”

Together, Johnson and Baldwin work with interns and volunteers on multiple wildlife projects on Martha’s Vineyard. Using new geotagging technology they are on the hunt to catch the shorebird native to the area…willets. Johnson said that geography plays a huge part in catching willets. Sand dunes can offer a great advantage, whereas tall plains of seagrass are not too helpful.  

“So, this is a really tough nest because it's in really tall grass," she said. "So it limits our ability to use a couple of the kind of traps that we use to catch willets on the nest. It’s a female that we are trying to catch, when the female is incubating, the male’s job is to be on alert and a sentinel. So, he called her and told her that we were coming, and she scurried out before we got there and left the nest. This female we called her Can’t Even because, we can’t even, we been trying to recapture her for a long time and she's been wise to our methods and this little area here, we call it the fortress of solitude, because its really a tough spot.”

Sometimes it takes more than just different types of nets to lure willets. Sometimes you need to get creative.

Baldwin and her intern Sammi Chaves bring me to Poucha Pond on Chappaquiddick island. They also brought a new variety catching tactics. Instead of using a bamboo net, Baldwin and Chaves brought a metal grate with small plastic nooses wrapped around, called a noose carpet.

This device works when a willet lands on it by cinching its legs with small noses, making it unable to fly away. After placing the noose carpet on a small cedar tree, the duo divide themselves around the dunes and marsh area. Baldwin takes position on the left far end, and Chaves on the right. Now, they wait.

“He or she keeps standing on it, so, I think that is probably where it wants to be," Chaves said. "So, if we put the noose carpet there…maybe it will work? But they can see it so, a lot of the time they will pick another cedar tree. So what we will do is we will put the noose carpet on the cedar tree and push them onto the cedar tree, so we wont them use the other cedar tree….and force them to use the one with the noose carpet…or at least try."

Strategies are helpful, but willets are intelligent and unpredictable. Baldwin and Chaves try to set up a decoy on a cedar tree to lure the birds onto a noose carpet. But it doesn’t work out as planned.

“I was walking down towards the birds were hoping to keep them from going farther away and bring them and closer to were the noose carpet was," Chaves said. "It did prove to be unsuccessful, but we are going to move ourselves down that way and hopefully and have a little more success.”

Unfortunately, no willets are caught at Poucha Pond, even with the use of a willet-call decoy to attract them…the birds are too aware of the noose carpet trap. But, Johnson has a more stealthier alternative.

“You can use a remote triggered nest trap, called a bow net, which is a small net that you fold back on itself," she said. "And then you spring it, and it goes WOOSH. And it puts like a little hoop on top of the nest. So, you wait for the bird to come back to the nest for an hour or so, and get all cozy sitting there and then you spring it remotely with the bow net trap.”

Sometimes you just can’t catch a willet. And oftentimes you can blame the female’s mate.

“When you got a really alert male," Johnson said, "and he’s ready to protect the nest and protect the female, you get alarm calls and you cannot approach the nest.”

When you're trying to catch a male it’s much easier because the female won’t alert him. Why? It’s another mystery of the willet.