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Posts Tagged ‘Common Eider’

Hello again from Ship Island! Jill and I have been off the island for about 4 days as part of a mid-season break provided for us by the refuge staff. Now that we’re back and catching up on our work, here’s the second part of  ”Citizens of Ship Island”, as promised.

In my last post, I wrote about the songbirds that call Ship Island home during the summer. This time, it’s all about water birds of all kinds. While we have songbirds breeding right on the island, most of our seabirds and shorebirds are found on the three islands surround Ship: East Barge, West Barge, and Trumpet.

Take for example the Great Black-backed and Herring Gulls. Because both of these species of gulls will eat tern eggs and chicks, they aren’t permitted to breed on Ship itself. Both species, however, make (usually unwelcome) appearances on Ship and have nests on both the Barges and Trumpet. Great Black-backed Gulls are one of the biggest North American gulls, with a wing span of over 6 feet while Herring Gulls are a bit smaller. Check out the photo below for a comparison.

Great Black-backed Gull on the left, Herring Gull on the right

Also nesting on Trumpet are North America’s largest sea duck: the Common Eider. While the females may look like a standard brown duck, the males have flashy black and white plumage.

A handsome Common Eider male with two Common Terns on the beach of Ship Island

Most often we see these large ducks paddling around with their heads under the water before they dive down for mollusks and other invertebrates. As you can see, they are quite a bit bigger than a tern!

A male Common Eider on the left, a female on the right, and a Common Tern in the middle

Eiders are best known for the incredibly warm down they produce – the females actually line their nests with these soft feathers. Eider ducklings take to the water the same day they hatch. Females with ducklings will gather together to form crèches, made up of several females and their young, to help protect the ducklings from predators like gulls. Although eiders pose no threat to our terns, they find people a bit intimidating and so prefer to nest on Trumpet.

A female Common Eider and her ducklings

Out on West Barge, in addition to lots of Great Black-backed Gulls, we have a colony of Double-crested Cormorants. Like the eiders, the cormorants prefer to nest on human-free islands, but we see them every day in the waters around Ship.

West Barge’s Double-crested Cormorant colony

They also sometimes come to shore to gather seaweed for nesting materials, like the one flying off in the picture below. The colony on West Barge seems to be doing well – we’ve counted about 50 cormorants on the south side of the island.

A Double-crested Cormorant flies off with some nesting material.

Not all of the water birds find us so intimidating. We have several Mallards on and around Ship, including a female with her ducklings. We usually see this fluffy gang paddling around in a swampy depression in the middle of the island.

Female Mallard paddling with her ducklings. Photo taken by Jill


Finally, we have our beloved Spotted Sandpipers. The only shorebirds that nest on Ship Island, Spotted Sandpipers are easily identified by their “teetering” behavior: as they walk (or even when they stand), they bob their rumps up and down. The purpose of this behavior is still unknown, but it makes them easy to pick out of a crowd.

An adult Spotted Sandpiper on the shores of Ship Island

We have several pairs of these nesting on the island, and we recently spied our first chick running around on the beach. Compared to other young birds, Spotted Sandpiper chicks are quick and agile. This one was already practicing its teetering! Jill snagged a photo of him bobbing his way down the beach.

A Spotted Sandpiper chick out for a run on the beach

Next time, the terns will be back in the spotlight with fuzzy chicks galore!

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We are packing our gear and cleaning the cabin!  Jennie and I head back to the mainland today and we wanted to give you one last update on our season.

We crossed off each day after we finished the dinner dishes. Its wild to think that its all over for 2011...

Census

The Gulf of Maine Seabird Working Group (GOMSWG) census was started on June 17, 2011, and finished on June 20, 2011.  The Tern nest count for the census was 484, with a Lincoln Index of 1.029, resulting in a corrected total of 498 Tern nests on the North End of Metinic.  This represents about two thirds of last year’s population.  Common Tern nests were marked with a blue flag, while Arctic Tern nests were marked with a red flag.  On the NE Point we identified 307 of 498 nests (61% of NE Point colony).  We counted 122 ARTE, 185 COTE nests.  We estimated that the colony was comprised of 40% Common Terns, 60% Arctic Terns. The South End of the island is privately owned and was surveyed by boat, 2 pairs of Terns were present, but no nests were confirmed.

Productivity

Fledging/reproductive success was low this year for Arctic Terns (under the 1 chick/nest USFWS goal), but Common Tern productivity improved from last year and met this goal.  The Arctic Terns suffered from widespread predation events early in the season which resulted in the loss of many eggs and young chicks.

Provisioning

We were able to follow 6 Common tern and 8 Arctic Tern nests throughout the season, for a total of 96 observational hours and 599 feedings. COTEs fed at an average rate of 1.6 feedings/hour, while ARTEs fed at 0.7 feedings/hour.  Both Arctic and Common Terns delivered Atlantic Herring most frequently to their chicks consisting of about 55%and 30% of their diet respectively.  Butterfish was the next most frequent delivery for both species, making up about 30% of deliveries.  Herring deliveries gradually declined and butterfish deliveries gradually increased as the season progressed.  Feedings overall slowed considerably starting in the third week of July especially for Arctic Terns.

Guillemots

32 Guillemot nests were located with a hatch success of 62% and an egg depredation rate of 12.9%.  This data is not a complete set because of the number of guillemots incubating through all checks.  Three adults were still incubating at the end of July, so hatch success could be higher than calculated. 19 chicks were found and 14 were banded, weighed, and measured.

Petrels

53  Leach’s Storm-petrel burrows showed signs of activity (smell, fresh piled dirt, activity at night) early in the season, however only 7 were noted to have eggs or adults present at the end of July.  At the end of our field season, 17 burrows were no longer active and 29 still showed some activity yet nothing could be seen with the burrow scope.

Common Eider

Eider numbers were very low this year averaging only 50-100 eiders at each morning count. Previous years Eiders had averaged between 150 and 300 for morning counts.  Only 30 observations of eider crèches were documented (at least 4 separate crèches).  Five eiders were banded by USGS and MDIFW.

Incidental Sightings

Species highlights: Northern Gannett, American Oystercatcher, Razorbill, Atlantic Puffin, Whimbrel.

We had a tremendous amount of fun out here this summer, and we hope you all enjoyed being able to follow along!  If we peaked your intrest and you would like to get involved or support our efforts makes sure to check out the Friends of Maine Seabird Islands site: http://maineseabirds.org/html/home.html!

Signing off!

-The Metinic Crew

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Eider Parade!

These Common Eider hens decided that our front yard was the safest route for leading their ducklings to the water!  I just happened to glance out the window at the right moment.  We thought you may appreciate how adorable the scuttling little ducklings are.  We are truly lucky to be out here and so close to all of these birds.

-The Metinic Crew

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Kelsey and Jennie make their way through the Bayberry.

This week on Metinic we had the opportunity to participate in the annual Common Eider round up!  We grabbed our boots and our nets and headed into the brush!  Now finding an Eider in the bushes isn’t easy, and getting a net in front of her before she can flush to the water is even harder.  Jennie disagrees; she scared one right into her net!

Maine Department of Inland Fisheries and Wildlife biologist Brad Allen bands an Eider hen that Jennie caught.

Common Eiders are devoted mothers.  They do not feed during incubation, and may lose up to 45% of their initial body mass!  Within the first week of incubation females will leave the nest to drink freshwater, then stay on their nests around 20 days unless disturbed.   Once ducklings hatch, the hen leads them to the water and nonbreeding hens join them to create a protective “crèche”.  These crèches are crucial for defending the ducklings against predation from Great Black-Back Gulls

Common Eiders are an important harvest species in Maine, and require management to protect the populations from decline.  Mark and recapture roundups like ours on Metinic, combined with band reports from hunting mortalities allow biologists to set bag limits.  In recent years those limits have had to decrease in response to increased hunting pressure.

A Eider in the hand is definitely worth two in the bush on Metinic, Charlie didn't catch a thing!

These long lived ducks have reproductive models more similar to seabirds then other ducks.  They have deferred sexual maturity, small clutches, and long lifespans. Because of this, females have the option of taking a year off from breeding.  Traditionally there were 300 Common Eiders nesting on Metinic Island, this year it was estimated to be about 25 on the north end.  There were plenty of female Eiders on the water so hopefully they are just taking a year off.  At least our new ducklings will have a lot of “aunts”!

A giant Metinic Thank You goes out to Maine Departmaent of Inland Fisheries and Wildlife biologists Brad Allen and Kelsey Sullivan, and U.S. Geological Survey biologist Dan McAuley.  We had a blast on our Eider round up!

~ The Metinic Crew (Charlie Walsh, and Jennie Wiacek)

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