Outdoor Radio: Counting Endangered Terns On Champlain's Papasquash Island

May 14, 2017

Hard hats in hand, Biologists Kent McFarland and Sara Zahendra head to the docks at Lake Champlain. They are taking a boat to Papasquash Island, owned by Audubon Vermont, to help count the new breeding population of common terns.

Leading the excursion is Mark LaBarr of Audubon Vermont, who has been taking this trip for over 20 years.

“The common tern is a state endangered species, and because of that, and with help from the Vermont Fish and Wildlife Department, Audubon has been visiting the islands,” explains LaBarr. “We protect the islands by putting buoys out to keep people off … We work to just get an assessment of the numbers of birds that are out there, how many chicks are getting off, and just keep track of them over time.”

Zahendra asks LaBarr what happened to terns that caused the Audubon to have to protect them. “Back in the late '60s there were probably 300 to 400 pair of common terns on Lake Champlain, and over the course of the next 20 years, their numbers basically dropped to about 50 pairs,” he says, adding that a lot of factors contributed to the rapid decline in terns, including the population explosion of ring-billed gull and human disturbance. “The work is really designed to bring the numbers back up,” he says.

Their efforts have been successful. “Two years ago we had our highest count of birds. The pairs were up to about 275 breeding pairs,” says LaBarr. He says the numbers have been going up each year and that they are proud of the work they’ve done. “Audubon owns the island, protects the island. I’ve been doing it for a long time. It’s great to go out and visit and hear the terns and smell the terns,” he says.

Papasquash Island, owned by Audubon Vermont, is very small, rocky and has a flat top to it.
Credit Kent McFarland

As the biologists reach the island, LaBarr explains that he usually turns the boat engine off and drifts by the island to get the adult tern count.

“Are they going to start attacking our heads yet?” asks Zahendra. (This is where the hard hats come in handy.)

“Not until we get up on the island,” answers LaBarr.

“So you’re calling this an island, but that’s a big rock,” says Zahendra. LaBarr agrees: The island is very small, rocky and has a flat top to it.

“As you can see, when we approach the island the birds are getting a little more flightened. Usually they’ll lift and resettle, but they realize we are going to be up there,” says LaBarr.

At first glance, Zahendra and McFarland note that the birds are gorgeous.

LaBarr, Zahendra and McFarland walk on Papasquash Island. LaBarr notes that when you hear the birds making a certain "cacaca" noise, you'll start to feel them pecking on your hard hats.
Credit Chris Albertine / VPR

“One of the things we do every year to minimize human disturbance on the island is we put four buoys around the island … Human disturbance can be a problem, but for the most part, you know, the birds have gotten pretty used to having fishing boats. There are very few people who would actually land on the island,” says LaBarr.

“Yeah, you’d get dive-bombed and pooped on,” adds Zahendra.

Terns feed off of the top 6 inches of the water, according to LaBarr. "They don't enter the water when they are feeding, so they are kind of like flying tweezers," he says.
Credit Kent McFarland

LaBarr explains that at this time of the year, the vegetation on the island hasn’t come up as much, so he can get a good estimate of the number of birds just by counting those incubating in plain site. He does note that the birds are always coming and going, so the numbers on the island can change constantly. “Right now I can see some terns flitting around up there. Just keep your eyes open. Certainly, once we get close to the island and when we land in order to get the nest data, and hopefully find some chicks, the birds will be right there with us,” he says.

LaBarr notes that when you hear the birds making a certain “cacaca” noise, you’ll start to feel them pecking on your hard hats. “Basically, they feed off of the top 6 inches of the water, they don’t enter the water when they are feeding, so they are kind of like flying tweezers,” he adds.

Tern eggs and chicks are speckled with greenish-brown color, helping to camouflage with the nest.
Credit Chris Albertine / VPR

McFarland asks if there are a lot of new nests due to the weather. “I think what we’re seeing is some late nesting birds, but I also think we’re seeing birds that have re-nested …” LaBarr answers.

“You look at these nests in front of us, the eggs are speckled with greenish-brown, and sitting down on that nest right there, we really do have to be careful we don’t step on them. They are camouflaged,” says McFarland.

“And the chicks are too,” adds LaBarr. “We found those chicks in the other nest and they kind of look just like the eggs.”

Scattered on the island are tiny, wooden triangular shelters that Audubon Vermont calls chick shelters. “They give them a place to get out of that weather, because if they do get wet at this time, they’ll die of exposure. Within a couple—  two, three, four — days, they start putting on other feathers and they can thermoregulate a little better, but the first two days are really key,” says LaBarr.

Scattered on the island are tiny, wooden triangular shelters that Audubon Vermont calls chick shelters. LaBarr explains that these help to keep the chicks dry until they are old enough to thermoregulate themselves.
Credit Kent McFarland

They find several newly hatched tern chicks on the island, including one LaBarr estimates is only about a day old.

“How fast is he going to grow? When can he fly?” asks McFarland.

“About 18 to 21 days,” says LaBarr. “Those parents are going to be busy bringing those small fish back and forth to the two in this nest that we found.”

LaBarr seems to be pleased with the count they’ve taken on their trip out to Papasquash Island. “We have our first new hatches of the year, we have a lot of new nests out there. This is great,” he says.

You can find more information about Common Terns at these links:

Vermont Common Tern Recovery Project.
Vermont Breeding Bird Atlas.
A map of sightings on Vermont eBird.

Outdoor Radio is produced in collaboration with the Vermont Center For Ecostudies with support from the Jack and Dorothy Byrne Foundation.

This episode was first broadcast on June 18, 2015.