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Posts Tagged ‘Terns’

This weekend the Ship Island crew headed over to Pond Island to take part in a beach cleanup along the shore. Morgan and I, as well as several other volunteers, collected dozens of trash bags filled with lost buoys, cans, bottles, and more. This year is the first year the group will be able to actually recycle the plastic that was collected. Through the company, TerraCycle, our collection of plastics, no matter how dirty or broken they may seem, will be sent over to be thoroughly cleaned and re-purposed. Typically, most objects made out of recycled plastic only consist of about 30% reused material. Though it doesn’t seem like a lot, or maybe even not enough, if the concentration is increased then the new object becomes closer to the end of its lifespan and can no longer be reused. It was good to get off the island and spend some time with others working to keep our environment clean, but we’re glad to be back on Ship with our terns!

 

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Section of a boat that was found washed to shore. We needed all hands on deck to carry this one over!

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Beach Cleanup Volunteers

Back home on Ship, we’ve had problems with other birds predating on our Common Terns and their eggs. Currently, Great Black-backed Gulls, Herring Gulls, American Crows, Peregrine Falcons, and Northern Harriers are our main concerns. Almost every day we spend two hour shifts in the blinds to observe the tern behavior and keep an eye out for any of these predators that might pass by. During the evening we’ve been marking nests with predation sticks so we can notice if any eggs have gone missing. By doing this we are also able to get a good idea on how many terns we really have on the island. It doesn’t look like it, but so far we have counted over 500 nests, which means we have over 1000 terns! So far so good! In a few days we will be doing a GOMSWG census which will give us an even closer estimate on our tern population size. We’re excited to share the results with you next week!

-Amanda

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Things are getting busy on Metinic. Common and arctic tern eggs typically hatch after about three weeks, so we’ve been making preparations before we have an abundance of chicks scurrying around. Based on when the first egg was found, we’re anticipating the first chick to pop out before next weekend. Ahead of hatching, we will conduct a census of the colony, which in turn has several precursors that we have been working on this past week.

As we have two species of terns on the colony, it is important to determine an approximate ratio of these two species. Nests cannot always be reliably told apart without looking at the bird attending. Arctic terns tend to nest higher on rocks and usually only have two eggs, while common terns typically nest in grassy areas between the rocks and will have a complete clutch of three eggs. However, exceptions abound. Perched up in the blinds, we sit and watch as adult terns fly in to their nests. Then we note the locations of a few nests and run down to place a colored flag near the nest: red flags for arctic, blue flags for common. Based on the 152 nests we flagged, it appears that we have a pretty even split, with arctic terns slightly more prevalent.

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Red and blue flags blowing in the breeze around arctic and common tern nests

Another task before the census is the placement of predation nest markers. While we will also be monitoring nests for predation in our productivity plots later in the season, these markers allow us to note egg predation early in the season and outside of the densest parts of the colony. Tongue depressors are painted, and then placed around nests in the colony, denoting the number of eggs in the nest when placed. These will be collected during the census and any nests with fewer eggs than written on the stick will be noted as likely depredated.

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This two egg nest marker will be easy to spot with its brilliant chartreuse top

Metinic isn’t the only island in the area with breeding seabirds. On Wednesday, we went along with Refuge staff to nearby Two Bush Island. The shrubby vegetation around a small lighthouse serves well to conceal a few eider nests, while some guillemots likely nest in the rocky ledges. On our way back, we circled Crow Island to check on an eagle nest. Two adults were around, but we couldn’t see any eaglets from the boat.

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Two Bush Island lighthouse surrounded by thick brush

This weekend is the annual Metinic Island sheep shear. We helped to drive most of the sheep from across the island to a corral on the southern end, where they are processed. Watching the shearing in action, it is really amazing how much wool some of these sheep have grown. Hopefully some of that wool will be made into warm layers so that those wearing it can be as cozy as the sheep out here off the coast of Maine.

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Sheep from the drive waiting to get sheared along with a few that had already been

Until next time!

Mark

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Arctic Terns have arguably the most impressive migration of any bird – they travel from the Arctic to the Antarctic and back again just about every year of their lives.  While we’ve known for a while where the terns travel, how they get there has been something of a mystery. Do they travel along the coastline? Do they take a direct route from Maine to the Antarctic coast? Do they do a marathon flight from pole to pole, or make pit stops along the way?  These questions were nearly impossible to answer until very recently, for the simple reason that following a single tern (or even a flock of them) is nearly impossible. Terns are small birds – a little over 100 grams, or 3.5 ounces – so they can’t be equipped with heavy satellite tags. They also do mostof their traveling over water, so the odds of spotting a tern on its migration are slim.

Enter the light-level geolocator, here to solve these problems and answer many of our migration questions

A geolocator, wrapped in a waterproof cover, attached to the leg of an Arctic Tern

A geolocator, wrapped in a waterproof cover, attached to the leg of an Arctic Tern

Four years ago, in the summer of 2010, the Refuge deployed 30 geolocator tags on 30 separate Arctic Terns. These tiny tags are lightweight enough that they don’t hinder the terns as they travel (in fact, they’ve been used on even smaller birds, like Purple Martins). They work by using detecting light levels and recording the time of sunrise and sunset every day. Since the length of day and the time of sunrise and sunset are slightly different at every point on the globe, this information can be converted into a rough map of everywhere the tag, and by extension the tern, has been.

A pretty miraculous little gadget, isn’t it? But there’s a catch: to reduce weight, the geolocators don’t transmit the data they gather, they simply record it. To get at all that information, the tag must be retrieved and physically attached to a computer. This means the tagged birds must be recaptured and the tags removed before they do us any good.

A geolocator (right) and a field-readable band (left)

A geolocator (right) and a field-readable band (left)

Recapturing a bird can be difficult. The best way to do so is to find the bird’s nest, and use a trap that springs while the bird is incubating. That, however, requires the bird to be able to find a mate. Last year on Metinic, Zak and I spotted a geolocator-equipped tern who had eluded capture for 3 years, but we couldn’t get our hands on him because he didn’t have a mate or a nest.  He spent all summer trying to court various female terns with fish, but there were no takers.

Hard to believe such a good-looking guy couldn't find himself a date

Hard to believe such a good-looking guy couldn’t find himself a date

This year, our lonely tern returned and found himself a mate. Syd and I set up a trap called a bow net trap, which is triggered by the tern attempting to incubate a set of fake wooden eggs (the real ones are safely stored in a blind so they aren’t crushed by a struggling tern). It took a couple of tries, but today we succeeded in capturing the handsome gentleman we have nicknamed Giovanni (Geo, for short).

Syd and Geo

Syd and Geo

Geo was released back to his mate and eggs, probably glad to be rid of his extra baggage. The geolocator will be returned to Refuge staff, who will hopefully be able to use it create a roadmap of Geo’s travels from the past four years. That could be up to eight traps between Maine and Antarctica – more than 70,000 miles!

Geo, free of the geolocator and sporting a shiny new band

Geo, free of the geolocator and sporting a shiny new band

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Hello from Metinic! I’m Amy, and If you’re a regular reader of this blog (there must be a few of you out there!) you might remember me from last summer.  This is my third summer working on a seabird island for MCINWR, and I can’t tell you how glad I am to be back on Metinic. Joining me this year is Syd, a recent University Maine graduate, and Maine native. This is her first summer living on a seabird island. Our first task on the island has been a bit of spring cleaning. Over the winter, trash and debris have a tendency to wash up into the colony, so Syd and I have been picking up bags of trash including the ordinary (plastic bottles, aluminum cans, a lost sandal or two) and the unusual (snow shovels, cans of cheez whiz, and a section from a car dashboard).  We’ve also rounded up some buoys. IMG959995 Lots of buoys. IMG953530 Our other job for the first few days on the island was to send Metinic’s year-round wooly residents south for the summer.   The sheep of Metinic normally have the run of the entire 300+ acres of Metinic, but during the summer, they are restricted to the southern end of the island so that they don’t disrupt the colony or accidentally step on a nest. Thanks to help from Refuge staff and volunteers, we managed to herd the whole group out of the colony and down to their summer home.

Syd helps a lamb that was separated from the flock

Syd helps a lamb that was separated from the flock

Our terns seem to be appreciating their cleaner surroundings. About 300 of them have been house-hunting and checking out potential nest sites

Common Terns going house hunting

Common Terns going house hunting

Best of all, a handful of birds have really settled in: we found our first eggs yesterday!

Our first egg!

Our first egg!

The countdown to chicks has begun! In the meantime, we’ll be sure to update you on the other happenings on Metinic, so stay tuned! –          Amy

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It’s the end of the season and migration time for all of us. Hard as it is to believe, Zak and I have already been off Metinic for more than week.  We’re not the only ones heading out – our tern chicks will soon be off on their own travels.
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Common Terns will head for South America, a pretty long haul for chicks only a few weeks old. The Arctic Terns have even farther to go – all the way to Antarctica! Lucky for them, they’ve got parents to guide them. Chicks will often complete their first migration by following Mom or Dad. This is because tern parents usually have lots of migratory experience – Common Terns can live to be twenty years old, Arctic Terns more than thirty, and they typically migrate every year.

 

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The rest of our feathered friends are getting geared up for migration too. Shorebirds that we haven’t seen since May are flying south from their Arctic breeding grounds and stopped by to say hi before we left. It’s only a matter of time before the songbirds head out, too.
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It’s been a pretty good breeding season for our terns, especially in light of last’s years troubles. The Arctic Terns in particular did very well thanks to good food, good weather, and few problems with predators. We hope this bodes well for future years on Metinic. We (or next year’s crew) will let you know, starting next May!

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Thanks for following along with our work here on Metinic. Zak and I have had a fantastic time out here and we hope you’ve enjoyed reading about what we and the birds have been up to.

Wish our terns chicks luck!

– Amy

(All photos by Zak)

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Although I may have spent the first few posts talking about songbirds and gulls, terns are our focus around here. These feisty seabirds are what bring us to Metinic, so it’s high time I let them have their “tern” as the center of attention.

Metinic’s terns, both Common and Arctic, had a rough season last year. Because of an unfortunate combination of bad weather and lots of egg-eating gulls, the terns were forced to abandon their nests shortly after they began laying eggs.

A Common Tern soars over Metinic - Photo by Zak

A Common Tern soars over Metinic – Photo by Zak

We were all holding our breath to see if the terns would take a chance on Metinic again this year. Even if they did, we had no idea how many would actually return.

After completing our annual tern census this week, we’re pleased to say we have 350 pairs of terns nesting on Metinic this year!

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An Arctic Tern on the nest – Photo by Zak

We’ve also had chicks of both species start hatching – more than fifty of the island’s most adorable residents have popped out of their shells. The adult terns are already hard at work bringing in enough fish to feed their new chicks. It will be about a month before these little fluffballs are ready to fly, so the adults have their work cut out for them.

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An Arctic Tern brings back a fish for its chicks – Photo by Zak

These days, Zak and I are out banding chicks in our productivity plots so we can chart their growth. Unlike tern parents, we can’t tell chicks apart without some kind of marker, so all productivity chicks are banded within a day or two of hatching.

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Amy banding a tern chick – Photo by Zak

We’ve also been trapping and banding adult terns. As with gulls, the best way to trap a tern is on their nest. We replace the eggs with wooden dummy eggs and set a trap that springs when the adult returns to incubate. We then band the tern and take a few measurements before releasing it. The dummy eggs are removed and the real ones are put back in the nest.  The terns aren’t too happy with the process, but they always seem to return to the nest within 15 minutes of being released.

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Banding an adult tern – Photo by Zak

By banding adult birds, we have a better chance of seeing the bands again – any breeding adult has already proven its ability to survive at least one migration, so it’s likely that it will survive another year. Some terns can live to be more than thirty years old, and every time we see the band we add another piece of information about that bird’s life.

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An Arctic Tern – Photo by Zak

You may notice us wearing some strange looking hats in our photos. While we’d like to pretend these are the very latest in high fashion, they’re actually a practical method of tern defense. When protecting their nests, adult terns aren’t afraid to peck an invader, be it gull or eagle or human, on the head. They typically aim for the highest part of the body, so adding a flag to the top of you hat is a good way to keep your head from getting pecked.

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Tern attack! Adult Common Terns defend their nests from an invading mammal (aka Amy) – Photo by Zak

We’ve got a few more terns stories coming up, plus an update on some of our other seabirds, like Black Guillemots and Leach’s Storm Petrels, so stay tuned!

-Amy

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Our Island Home

The cabin we are going to call home for the summer.

Finally, after weeks of anticipation and planning, we (Julia and Katie) have arrived at the island we are going to call home for an entire summer. Our island is called Ship Island, and it lies in Blue Hill Bay, Maine, just a few miles off shore. At just 11 acres, the small island will be called home to not just ourselves, but to a variety of various song birds, sparrows, and seabirds. Our focus, of course, will be on the seabirds, and we are looking forward to a wonderful summer with them.

May on the islands provides a fantastic opportunity to witness the migration of birds. As islands along critical oceanic migration routes, the Refuge’s islands are essential to providing migrating birds a place to refuel and refresh. For the biologists, it is an exciting time to witness new species and observe them closely as they forage voraciously in trees and shrubs just feet away.

Northern Parula

Northern Parula from the back window.

Like Petit Manan and other islands, Ship Island has been privy to sundry migrants: 72 in total at the close of today. It seems that nearly every morning we wake up to a new bird song. This morning, it was the Bobolink with his “R2D2” voice.

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Bobolink singing his “R2D2” song in front of a tern blind and West Barge Island

But the migrants are not the only exciting birds we see here – shorebirds flock to our sandy beaches, scouring the rack line for tasty morsels as they probe incessantly with their long bills. Lately we have been seeing up to 50 Black-bellied Plovers, still in the process of molting into their striking summer plumage. Others have included Least, Semipalmated, and Purple Sandpipers, Ruddy Turnstones, Dunlin, Willets, Whimbrels, Short-billed Dowitchers, Greater and Lesser Yellowlegs, Semipalmated and Piping Plovers.

Until next time,

Julia

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