Razorbills, puffins, terns, guillemots – thousands of seabirds flock to Maine islands each summer. They socialize, lay eggs, feed their chicks, and as the summer cools into autumn, they depart.
Biologists have witnessed this natural cycle for decades as they’ve worked to restore seabird colonies off the east coast. Yet little is known about what happens when the birds leave the islands, in the hours that they forage for their chicks and during the winter months, when they migrate.
This lack of information about seabird flight patterns has become a concern to biologists as plans for offshore wind energy development come closer to fruition.
In response, the U.S. Fish and Wildlife Service has recently begun using a combination of radio and satellite telemetry to trace seabird migration patterns and pinpoint crucial foraging and nesting areas.
“What we’re trying to do is be more proactive and gather information to help identify areas that are really important to seabirds, then provide that to (wind power station) developers,” said USFWS biologist Linda Welch, who studies seabirds on the 58 islands of the Maine Coastal Islands National Wildlife Refuge.
“We’re concerned that (seabirds) could fly into the turbines, particularly if it’s really foggy,” Welch said. “These birds are already traveling long distances, and if they have to fly around a wind turbine array – some of these they’re proposing are hundreds of turbines – will they have the ability to make the same flights, or will this be too much for them?
“We’re hoping we can find a place that will be good for wind development that will also not be harmful to seabirds.”
Maine seabirds become high tech
Since 2010, Maine biologists have used three types of devices to track the movement of seabirds – geolocators, nanotags and satellite transmitters. Each device has its benefits and downfalls.
A geolocator costs about $180, according to Welch, and records the approximate location of a bird – give or take 110 miles. Its weighs just 1.6 grams and determines the location of a bird based on the length of daylight and the time of sunrise and sunset.
“Geolocators can track migration, but they aren’t very accurate,” Welch said. “They give us a general idea of where the birds are spending time, but it’s not accurate enough for us to identify foraging grounds or a colony they’re visiting.”
In 2010, Maine Coastal Islands NWR, in collaboration with the National Audubon Society, deployed 30 geolocators on Arctic terns breeding on Maine’s Metinic Island and Eastern Egg Rock. The following year, they recaptured the terns to recover the data, which is stored inside the devices. The project confirmed that Arctic terns have the longest known annual migration, an average of 55,250 miles. Arctic terns can live for over 30 years, so during their lifetime they may fly an equivalent of 66 times around the Earth or three round trip flights to the moon, according to the USFWS.
Putting a price on wildlife
In 2012, the USFWS biologists in Maine received a federal grant of $94,000 to collect more specific information about seabird flight patterns by using nanotags and satellite transmitters. The grant proposal specified that this information would be used to inform wind power station developers of areas that are important to seabirds such as Maine’s beloved Atlantic puffin.
Satellite transmitters, costing about $3,000 each, provide instant and accurate coordinates of their carriers globally, making them ideal for tracking both migration and foraging behavior.
This summer, Welch is deploying solar-powered satellite transmitters on razorbills, a fairly large black-and-white seabird in the Alcidae family, the same family as the Atlantic puffin. And they bite hard, Welch said.
“It’s the first time this project has ever been attempted,” said Welch. “And we already have 10 (out of 11) tags out.”
Razorbills are listed as a threatened species in Maine, where an estimated 650 pairs currently breed on six islands. Since Maine is the southern limit of the razorbills’ breeding distribution, it is the only state with a breeding population.
“Nobody had attached a tag like this to a razorbill,” Welch said. “One of the amazing feats of razorbills is that they can dive up to 100 meters to find food, and so we were really worried about [the tag] changing the aerodynamic shape of their bodies and influence their ability to find food. So I worked with the developer of the tag to try to make it as small as possible and to kind of curve the front of the tag to try to make it as streamlined as possible. So far, so good.”
Welch began capturing razorbills on Matinicus Rock and Petit Manan Island in June. She uses a simple but effective trap called a noose carpet, handmade with a bait bag, cardboard and monofilament fishing line. She weighs the noose carpet down with bricks at the mouth of a razorbill burrow or along ledges, then sits in a blind to wait for the bird to walk over the trap and its legs to become ensnared in loops of monofilament.
Welch attaches the satellite tag to the skin on the bird’s back with sutures that will dissolve within 12 months.
“Hopefully we’ll learn a lot about this bird – where it goes in the fall, where it spends the winter, when it starts to return to Maine in the spring,” Welch said. “And then hopefully we’ll see it again in its burrow next summer.”
Small tags for small birds
One of the chief reasons razorbills were selected for satellite tracking is they’re large enough to carry the transmitters. Other seabirds, such as Atlantic puffins and terns, are too small, and the transmitters would hinder their movement.
For these smaller seabirds, biologists are using nanotags, coded radio tags that work with automatic radio stations.
“It’s a new technology where the receiver automatically scans for them, and you can pick up like 500 tags on one frequency,” Welch said.
Nanotags (about $175 each) have a limited range, making them ideal for collecting data about foraging behavior when birds are nesting in a colony.
As part of a pilot project to test this technology, the refuge tagged 21 incubating seabirds – Arctic terns, common terns and guillemots – on Petit Manan Island. The refuge also established automated receiving stations on Petit Manan Island, Petit Manan Point, Jordan’s Delight and Nash Island. Each station cost about $3,000, Welch said.
So far, biologists have learned a great deal of specific information about seabird foraging behavior from these tags. For example, they learned that one common tern nesting on Petit Manan Island made eight foraging trips to the Jordan’s Delight region in a 10-hour period while feeding two chicks.
Tracking birds the traditional way
In May, four young field technicians stepped onto Petit Manan Island, their home for the next 10 weeks while they conducted research on the island’s nesting seabird colony.
“Petit Manan is historically one of the most important seabird colonies on the coast of Maine,” said Welch.
The treeless, 16-acre island is the breeding grounds for Arctic terns, common terns, roseate terns, Atlantic puffins, razorbills, black guillemots, Leach’s storm petrels, common eiders and laughing gulls; and so far this summer, field technicians have identified 101 bird species that have at least visited the colony.
The island is also the location of Maine’s second tallest lighthouse, which the field technicians climb each morning to count birds from above.
In addition to Petit Manan Island, the refuge employs researchers to live on the Maine islands of Metinic, Eastern Brothers and Ship. And through a partnership, the National Audubon Society’s Project Puffin employs researched on the islands of Matinicus Rock, Seal and Pond.
On each island, they conduct an annual census of all nesting seabird species, monitor what adults feed to their chicks and record how many chicks survive to adulthood. Their presence on the island also helps deter predators.
“A lot of our monitoring we really try to be hands off and unobtrusive. We try to do mostly observation in silence, far away, through spotting scopes or binoculars,” said Christa DeRaspe, a field technician who has worked two seasons on the island.
However, on three special days each summer, the field technicians visit the nests and burrows, first to count eggs, then later in the season to secure leg bands on chicks and gather information hands on.
“It’s kind of the pinnacle of the whole field season,” said DeRaspe. “This is one of the rare days when we really get to dive in and get our hands dirty and actually be able to handle the birds.”
A unique number on each band gets recorded at the U.S. Geological Survey Bird Banding Laboratory.
“So if that bird is ever observed anywhere, people will know where it was banded and when it was banded – how old it is,” Welch said.
DeRaspe says that the field technicians call the chick-banding day “Christmas.” So this year on Petit Manan Island, Christmas landed on July 25.
Mapping out the future for seabirds
Today, when field technicians climb to the top of Petit Manan Lighthouse to observe the colony below, they have to duck under wires and maneuver around antennas and solar panels.
“It kind of ruins the view, but it’s important,” said Welch.
The historic lighthouse now doubles as a nanotag station, recording every tagged bird that flies by.
Eventually, the information gathered by these stations and satellite transmitters will be used to develop foraging habitat maps for seabirds, which will be used to guide wind turbine development away from areas that are important to seabirds.
This year, 11 razorbills will contribute to the project as they carry satellite transmitters during their migration.
“We’re hopeful we can get that last tag out next week,” said Welch. “And then we can monitor the birds through the rest of the summer, and hopefully for the next 12 months as they migrate to their wintering grounds and then come back to Maine, the breeding colony, next summer.”
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