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Posts Tagged ‘Great Black Backed Gull’

We found our first Common Tern nest, and couldn’t be more excited! Since finding our first nest, we have marked over 50 nests and have been monitoring them daily for signs of predation. We have taken note of close to 100 nests in our little colony, while keeping a close eye on any signs of unusual activity that could result in predation. We have been observing more and more terns visiting the colony and spending the night with us.

Yesterday, we headed over to Trumpet Island with refuge staff to conduct a census. While on the island, we walked 3m apart and counted all gull (Great Black-backed and Herring) and Common Eider clutches observed. Not only did we census Trumpet, we also got to observe a Great Black-backed Gull chick hatching!

Although the gull chicks were adorable, we cannot wait for our tern chicks to start hatching!

Your 2018 Ship Island Crew!                                                                                                                 ~Olivia and Bailey

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I can’t believe the season is more than halfway over! Yet there is still so much to observe and enjoy here on Petit Manan island. Recently we have begun to see the first of the arctic migrants, such as dowitchers and sandpipers. We have even seen some wandering passerines like mockingbirds, mourning doves and a fledgling robin. It says something about islands life when seeing a robin is a big surprise!

Unfortunately, the terns have had a rather bad stretch of luck. The combination of bad weather, predation and (seemingly) lack of food have had a huge impact on chick numbers. Parts of the island have done better then others. However, the colony doing okay. We even have a few fledglings flying around!

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Most disconcerting, for us researchers, has been watching the great blacked-back gulls swooping in and picking off tern chicks. They are efficient predators. It is equal parts interesting and terrifying to see them hunting. Jill got a great photo of one taking an eider duckling, so you can see one in action below.

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This weekend we have been joined by Bangor high-school student Max. He’s been an excellent addition to the crew and has been a great help with our research. Here he is examining a tern egg this evening.

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You’ve seen them on docks. You’ve seen them on dumpsters. They eat fish, french fries, and everything in between. But where do all these gulls come from? And where do they go once they’ve finished their lunch?

 Gulls can be found just about everywhere there’s water (and plenty of places where there isn’t). There are plenty of them around, and they’ve gained a reputation as garbage-eating pests.  But there’s way more to a gull than dumpster diving.

Some gulls, like this Great Black-backed Gull, are actually quite handsome! - Photo by Zak

Some gulls, like this Great Black-backed Gull, are actually quite handsome! – Photo by Zak

First of all, gulls are actually cousins of the terns we’re working so hard to protect out on these islands, and these cousins have a lot in common. Both terns and gulls prefer to nest in large colonies, and lay their eggs in nests on the ground. They’re both strong fliers, capable of traveling long distances over the ocean (although nothing quite tops the pole-to-pole migration of the Arctic Tern).  Males and females of both tern and gull species are almost identical (although males tend to be a little bigger) and both parents work together to raise their chicks.

So why have gulls done so well when terns are in trouble? It all comes down to food. Gulls are opportunistic – they’ll eat anything. Terns are picky eaters – they generally only eat fresh-caught food they pluck from the water themselves. Like a tern, gulls also love fish. But they’ll also eat mussels, urchins, crabs, and in recent years, human refuse. They’ve learned to follow fishing boats, flock to open dumpsters, or sometimes snatch food right out of people’s hands. So gulls have thrived on these new abundant food sources, while terns have been struggling.

A Herring Gull, Metinic's most common gull - Photo by Zak

A Herring Gull, Metinic’s most common gull – Photo by Zak

But we and the Refuge have been wondering, where exactly do Refuge Island gulls get their food? Does a gull here on Metinic fly all the way to the mainland for a meal? Or do they stay local and snack in the intertidal zone? This year is the pilot year of a study to answer those very questions with the help of GPS.

So, what’s the plan?

Step 1: Catch a gull.

The best way to do this is on the nest. The setup is simple enough: the gull sits on a string tied to a wooden prop. The prop separates into two pieces and the box falls down, capturing the gull. We replace the real eggs with wooden ones so they won’t accidentally get crushed. Sounds easy enough, right? Maybe not.

Some people call gulls rats with wings – and it’s not a total misnomer. Both rats and gulls are a lot smarter than many people think.  It took us several hours of trapping to catch our first Herring Gull.

Catch me if you can!

Catch me if you can! AKA, Gulls – 3, Biologist-0

Step 2: Attach a GPS Logger

These little boxes, called igotU tags, are programmed to take a GPS reading every 3 minutes for about 4 days. To attach one to a gull, we put it in a waterproof casing then tape it to the gull’s back feathers with extra strong tape. The tag is light enough that it won’t hinder the gull when it flies, and hopefully the tape will keep the gulls from preening the tag off.

igotU tag getting taped to a Herring Gull's back - Photo by Amy

igotU tag getting taped to a Herring Gull’s back – Photo by Amy

We also band the gull and take a few measurements to determine if it’s a male or female.

Zak checks a GPS tag

Zak checks a GPS tag on a Herring Gull

Step 3: Release the gull!

Amy releasing a tagged and banded Herring Gull - photo by Zak

Amy releasing a tagged and banded Herring Gull – photo by Zak

Step 4: Trap the gull again.

To get the data from the GPS loggers, we have to trap the gull again and remove the tag. Stay tuned for Part 2 to see what we find out!

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A GPS-tagged Herring Gull on its way – Photo by Zak

– Amy

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Petit Manan in the foreground and Green Island, connected to PMI by a rocky bar at low tide.

Petit Manan in the foreground and Green Island, connected to PMI by a rocky bar at low tide.

Last Tuesday, the crew headed over to Green Island, joined by biologists Linda, Sara, and Christa, and two SCA students, to survey the seabirds nesting there. After being dropped on the Northeast side of the island, we were all issued “egg rings,” PVC pipe connecters that are sized to allow herring gull eggs to pass through but not great black-backed gull. We formed a line going from the berm through the vegetation and headed west counting gull and common eider nests as we went along.

Egg ring for determining whether a nest belongs to a Herring or Black-backed Gull

Egg ring for determining whether a nest belongs to a Herring or Black-backed Gull

Common eider nests are hidden in the vegetation and beautifully made from the mother hen’s down feathers. She incubates her clutch of 2-9 eggs for around 25 days, only taking breaks in the evenings to drink and feed. After the first week of incubation females are reported to stay on the nest night and day unless disturbed. They go up to 3 weeks without leaving their clutch!

An eider nest lined with down.

An eider nest lined with down.

Skirting the western edge of Green Island, we found the first great black-backed gull chicks of the season and a Canada goose gosling. As we headed back to Petit Manan along the bar from Green Island we spotted two oyster catchers in the cove. In years past they have nested on Green Island, we are hoping they do so this year as well.

Andrea holding a Black-backed Gull Chick.

Andrea holding a Black-backed Gull Chick.

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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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This week on Metinic we have spent a few of our afternoons scouring the coastlines for Black Guillemot burrows.  Black Guillemots are the only bird of the Alcid family (the Puffin family!) nesting on Metinic since other Alcids prefer to stay farther offshore.  Black Guillemots nest in rock crevices along the shorelines and in order to monitor their nesting success we have to find their burrows! A burrow with an egg in it is pictured in our previous post “Eggcellent”.

As we were hunting for burrows, Charlie happened to stick his head in a crevice that was occupied, not by a Black Guillemot, but by a Great Black-backed Gull Chick! The chick was probably only a couple days old and screamed defiantly at us as we ogled at its cuteness.  We have also seen our first few Common Eider ducklings of the season swimming on the water with their mothers.  These groups of Eider ducklings and mothers are called “Creches”.  We have certainly been excited to have our first tastes of what is to come; chicks galore!

Great Black-Backed Gull chick!

~The Metinic Crew, Jennie and Charlie

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