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Posts Tagged ‘Arctic Terns’

Recently on Petit Manan Island we have been conducting chick provisioning studies. The purpose of these observations is to determine what prey species are being fed to tern chicks in order to see how prey composition is related to tern chick survival rates. We also record the time of the feedings, which chick is being fed, and the size of each prey item. Over the last decade the fish diversity on Petit Manan has increased. Although it allows us to see new and exciting fish species, it is not a positive sign for the terns. Increased feedings of invertebrate species such as moths, dragonflies, and other insects are also not great signs. Invertebrates and some fish are not as nutrient rich as herring and similar fish species, making them less beneficial for tern chicks. In 2006, common tern feedings consisted of 95% herring. Data from more recent years show that herring has dropped to 25% in 2010 and 34% in 2013 for common terns. Other fish species, such as hake and sandlance, have increased in feeding frequency. Although we do observe feedings of herring, hake, and sandlance, a large proportion of the feedings have consisted of tiny invertebrates and low quality fish species. Throughout the summer we have seen a total of 14 fish species, two aquatic marine invertebrate species, and at least 2 terrestrial invertebrate species being fed to chicks.

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Herring and Hake, respectively

Species like butterfish, lumpfish and three-spined stickleback are not high quality prey items because often tern chicks are unable to swallow the fish. Butterfish are disc-shaped, and often they are too wide for chicks to swallow. Lumpfish are a rough, round fish species that chicks can only eat when the fish are very small. Sticklebacks, as their name implies, have spines on their back that catch in the chicks’ throat when being swallowed.  We often find them uneaten near nest bowls.

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View from Chick Provisioning Blind

Some of the factors that are believed to be causing these changes in fish composition are ocean warming and overfishing. Over the last two years ocean warming has been affecting seabird populations on both the Atlantic and the Pacific Ocean. Seabirds are indicators of marine ecosystem health. Tern breeding pairs have been decreasing on Petit Manan Island for at least the past seven years, and this season marked the first time the total count of tern nests dropped below 1,000. As recently as 2009 Petit Manan was home to 2,500 pairs of terns. This could be indicating that the food availability in the Gulf of Maine is failing, and the terns are not able to find enough prey to be able to reproduce after their migration. To get a sense of what prey species are available to seabirds, we can use our provisioning data as a sample of the prey availability in the waters around Petit Manan Island. Also we can look at provisioning data to see how the rapid warming of water in the Gulf of Maine is affecting prey populations; in particular the herring population.

Using data from all of Maine Coastal Islands NWR and Project Puffin islands, we can learn what is happening in the Gulf of Maine system. This data will assist in monitoring the effects of a warming Gulf of Maine on the marine food web and what this means for the future of our seabirds and fisheries in Maine.

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Butterfish and Three-Spined Stickleback, respectively

I have really enjoyed doing these studies because it is exciting to watch the chicks’ daily activities and often the time goes by quickly. For our provisioning studies, each person has a blind that they spend time making observations from every other day. Returning to this specific area every other day is a great way to allow us to see the progress of the chicks and allows us to get to know each chick’s habits. These studies also allow us to see many different fish species as the terns bring them to feed their chicks. This is another great part of the job because it helps us work on our fish identification skills.

-Jimmy and Jill

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Hey folks! Jill and Morgan here! It’s been a surprisingly beautiful first week on Petit Manan Island; let’s hope it’s a sign for the whole season! The island has been lively thus far with approximately 200 prospecting Common and Arctic Terns, but we’re expecting many more to come! Although PMI isn’t the largest of islands, it still receives a good deal of visitors, especially early in the season when birds are migrating North – we’ve seen 61 species thus far! Not all our guests have been of the bird variety though; we also stumbled upon a juvenile Grey Seal on our rocky shores earlier in the week!

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Downy Woodpecker sighting!

The start of the season means preparing the island for all the work to be done in the months ahead. This means setting up observation blinds, for band resighting and future monitoring of foraging habits and chick health, as well as collecting marine debris, building burrows for Black Guillemots and Atlantic Puffins, and marking potential Leach’s Storm-petrel burrows. Daily Alcid counts from the top of the Petit Manan Light have also begun. On a windy day it can get rather cold up there, especially for Jill, who hasn’t quite gotten used to the Downeast summer having just returned from a seabird job in the Galapagos!

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Can you spot the Leach’s Storm Petrel burrow? We’ve been searching the island for these small holes in the ground this past we week, and we have found 170 potential burrows!

As we prepare ourselves for the research season ahead, the birds are doing the same. The puffins and guillemots are seeking out rock crevices and other sufficient and creative hiding spots for their burrows. The male terns are attracting their mates with a Sandlance dowry. The Common Eiders are seeking out areas of high vegetation to form their nests. And the Peregrine Falcons, Merlins, and gulls lurk about hoping to catch a bite to eat with all these new dining options in town.

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The Atlantic Puffins have already begun choosing burrows!

Till next time, here’s a joke to hold you over – Why did the Puffin have a stomach ache? Because it had Alcid Reflux!

Best,

Morgan & Jill

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Common Tern on flagpole

Common Tern on flagpole

Another year on PMI! After two weeks of cold weather and high winds the terns have finally started to nest. Maybe not in the numbers that we are used to but it’s still early enough for more terns to arrive and settle in for the nesting season. The Alcids on PMI don’t seem to waste any time, Atlantic Puffins and Razorbills have already laid eggs at least 3 days ago and hundreds of Black Guillimots are still prospecting all over the island.

First Actic Tern egg

Actic Tern egg

Atlantic Puffin egg

Atlantic Puffin egg

Razorbill egg

Razorbill egg

Tern eggs are made to blend in with beach materials such as sand, pebbles, and seashells but nesting up and away from the beach can be risky as some tern eggs can stand out against the vegetation and island dirt. Puffin and Razorbill eggs don’t need to be camouflaged as most Alcids nest in deep, dark burrows away from the eyes of arial predators. Puffin eggs are all white and a little smaller than the Razorbill’s bigger, speckled egg.

Banded American Oystercatcher resighted  on Green Island

Banded American Oystercatcher resighted on Green Island

Last week while over on Green Island, which is ajacent to PMI and only accessible at low tide, we resighted an American Oystercatcher! We know they try to nest there every year, but haven’t yet been able to resight one yet. Now with the numbers on his bands we can find out who he is.

Memorial Day cookout on PMI

Memorial Day cookout on PMI

Thanks to MCINWR we have a grill this year! Until next time….

Wayne and Julia

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Hi there!

I’m Meaghan. I’m a fourth year wildlife ecology major at the University of Maine at Orono. This is my first summer living and working on a seabird island, and I am very excited to be able to do so! Last summer I worked as an intern at the MCINWR visitor center in Rockland. While there, I had the opportunity to visit several of the seabird islands and very quickly ‘caught the bug’ for island life and could not wait to get out here myself.

Working as my supervisor is Derek. He is a fourth year environmental geography major at Central Connecticut State University. He is a Rhode Island native who has a lot of experience living and working on seabird islands in Massachusetts. However, this is his first year working with MCINWR on a Maine seabird island.

Our home for the summer (Picture: Meaghan Hall)

Our home for the summer (Picture: Meaghan Hall)

Our first week on the island was a lot of fun!

The first couple days were spent settling into our new home and familiarizing ourselves with the island. We conducted a sheep round up in order to move the sheep, that graze across the island during the off-season, off of MCINWR land so they do not disturb the seabirds during the nesting season. We have also been walking the island checking for and collecting garter snakes. In previous years these snakes have been observed preying on tern eggs and chicks, so we are trying to exclude them from the seabird nesting area. Lastly, we have been conducting morning bird counts. So far we have observed 31 different species of birds, including some migrants along with Common Eiders, Black Guillemots, Double-Crested Cormorants, and Spotted Sandpipers.The flock of Arctic and Common Terns that nest here annually have been observed visiting the colony in the morning hours and leaving around noon – presumably to look for nutritious fish. We were also pleasantly surprised to observe two Rosette Terns visiting our island! We are hoping that the terns will settle in the colony within the next week and lay their first eggs shortly after that.

Common Eider

Common Eider (Picture: Meaghan Hall)

Black Guillemot

Black Guillemot.  (Picture: Meaghan

We are very excited to be working as the technicians on Metinic this year and are more than happy to keep you updated on all things seabirds throughout the season!

-Meaghan and Derek

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As the heat of July settles in on Metinic, our birds, especially all those chicks we have, all need ways to keep cool.

Like humans, birds need to keep their bodies at a specific temperature. However, birds lack one of the key ways humans keep cool: the ability to sweat . So how does an animal covered in feathers and/or down make it through the summer without suffering from heatstroke? (No, the answer isn’t air conditioning or lots of ice cream)

A guillemot chick, sporting a black down coat for the summer

A guillemot chick, sporting a black down coat for the summer

This isn’t that hard for swimming seabirds like Common Eiders. Even though these ducklings are dressed in down coats for the summer, they don’t run the risk of overheating because they hop straight in to the cold coastal waters, sometimes on the day they hatch! Adults and ducklings alike will spend almost all their time in the water, occasionally hopping up onto rocks to preen.

Four eider ducklings tag along with mom

Six eider ducklings tag along with mom

However, chicks that aren’t ready to swim on day one can’t just jump in the water for a nice cool dip. Black Guillemots have found one of the simplest solutions to keeping their chicks comfortable – keep them out of the sun. Along with providing protection from hungry gulls, a guillemot’s burrow is shaded and cool. The chicks won’t leave the burrows until they are ready to swim, and then they can chill like the eiders.

A guillemot parent and two chicks (one freshly hatched) in a nice cool burrow

A guillemot parent and two chicks (one freshly hatched) in a nice cool burrow

So what if you’re stuck on the land, without a shady burrow like, say, a tern chick? You start out getting a little help from mom and dad. When tern chicks are small enough, they can be brooded by their parents. This behavior does double duty: it keeps chicks warm on cold nights and mornings, and provides cool (or at least cooler) shade during hot days.

An adult Arctic Tern brooding a chick

An adult Arctic Tern brooding a chick

Some chicks still seem to want to be brooded even when they are far too big.

A patient Arctic Tern parent "broods" a chick

A patient Arctic Tern parent “broods” a chick

If the parents are off fishing, something they spend most of their time doing once the chicks are a bit bigger, the chicks have to keep themselves cool. The simplest strategy is familiar to anyone with a pet dog: panting. Adults and chicks alike can be seen panting on hot days.

A panting tern chick

A panting tern chick

Once mobile, usually just a few days after hatching, tern chicks can seek out shade on their own by escaping under a rock or into the cooler grass. It isn’t unusual for us to find “chick tunnels” marking the path chicks take back and forth between their nests (where they get food from their parents) and a safe spot in the grass. We also put out three-sided structures known as “chick huts” in more exposed areas without much natural shelter.

 

A Arctic Tern chick (colored for a provisioning study) takes shelter in a shady chick hut

A Arctic Tern chick (colored for a provisioning study) takes shelter in a shady chick hut

Hope all our readers are staying cool as well!

-Amy

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We’re up to our elbows in chicks out on Metinic. In my last post, I mentioned that our tern chicks have started to hatch. A week later, our little fluffy friends are growing up fast.

Arctic Tern Chick

Arctic Tern Chick

We can often see our older chicks testing out their wings, although they are still a long way from being airborne.

An Arctic Tern chicks, stretching its wings

An Arctic Tern chicks, stretching its wings

Our resident Savannah Sparrows also have chicks of their own. These buzzy-sounding birds build a classic cup-shaped nest in grass on the ground. It can be easy to miss until you see the five squawking mouths.

A nest full of Savannah Sparrow chicks

A nest full of Savannah Sparrow chicks

Spotted Sandpipers are Metinic’s only nesting shorebird this year, and our first sandpiper chicks have made an appearance. Despite their small size and their resemblance to a cotton ball standing on a pair of toothpicks, these chicks are up and running around by day one. They do have a parent around to keep them out of trouble though!

Spotted Sandpiper adult (left) and chick (right)

Spotted Sandpiper adult (left) and chick (right)

Finally, we found our first Black Guillemot chicks. It’s hard not to love these little black puffballs. Guillemots are also the only alcid to lay two eggs at once, so guillemot chicks usually come in pairs.

Our first pair of Black Guillemot chicks

Our first pair of Black Guillemot chicks

Of course, Syd and I didn’t want to miss out on the fun of Guillemot Appreciation Day, so we celebrated in the most delicious way we could!

Our tasty guillemot cake

Our tasty guillemot cake

More updates as our chicks continue to grow!

 

-Amy

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For the past few weeks, a lot has been going on with Petit Manan’s tern colony!  We have been focusing much of our time on trapping and banding both Arctic and Common Tern adults, which is an essential part of our research.

In order to capture terns, we use two types of traps—the bownet and treadle trap—to catch adults on their nests.  First, we temporarily remove the eggs from the nest so that the bird does not crush its eggs if it struggles in the trap.  The real eggs are replaced with painted wooden ones, and a trap is set over the nest. Trappers then hide out in a blind and wait for terns to return.

The bownet is a spring trap that is set behind the nest cup and triggered when the adult sits on two monofilaments stretching over the “eggs.”  This trap has a metal frame and netting which springs harmlessly over the bird to contain it.  The treadle is a small cage trap with a door, which the tern must walk through to trigger its closing mechanism.

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a Common Tern being removed from a treadle trap

When a tern is captured, a researcher runs out from the blind to retrieve it and replaces the fake eggs with the real ones.  Each tern receives a metal band with a unique number on one leg.  Every Arctic tern also receives a field readable band with an alphanumeric code on the other leg, so that it can be easily resighted from a distance.  We take several measurements, including mass, wing chord (wing length), and head/bill length before releasing the tern.

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Julia banding an Arctic Tern

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Wayne releasing an Arctic Tern

By banding these birds, we can learn about their migration paths, longevity, nest site fidelity, and productivity.  Banded birds may be re-trapped or resighted in the future.  If a banded bird is found along its migration path or on wintering grounds, we can learn about where it has been travelling.  If a bird that was banded as a chick is later found as a nesting adult, we know that it has lived to breeding age and laid eggs.  Speaking of chicks…

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first Common Tern chicks hatched on 6/20

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first Arctic Tern chicks hatched on 6/22

We found our first tern chicks of the season on June 20!  Every day we are finding more chicks, and banding them as well.  As the season continues, we will be closely monitoring their growth, survivorship, and diet to learn about the colony’s overall health.  Stay tuned for more posts about these little cuties!

-Anna

 

 

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