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That’s all, folks!

Our summer has come to a close here on Eastern Brothers, and we’re finding it hard to say goodbye. This season has been very successful on many fronts, especially with black guillemot chick survival and fledging rate. From just last year, hatch success has increased 20%, nests with surviving chicks has increased 22.5%, and abandon nests has decreased by 20.8%! These number are very encouraging, also due to the fact that small mammal trapping has been a huge success this year compared to those previous.

The majority of our black guillemot chicks are fledging and are being seen floating around the intertidal with their parents, although we sort of feel like their parents after spending so much time with them.

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A black guillemot fledgling showing off its full-grown wings

The terns have officially left the island with their fledglings, a sign that their southern migration has begun. They’ll fly all the way to South America to fatten up during the winter months, making their way back up north to start all over again. We’ve had a high of three nesting pairs with 8 successful fledglings this season, and hope to see the same return with some more friends to get this island full of terns like Petit Manan!

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A tern fledgling trying out his alarm call on Eastern Brothers (photo cred: Steve M.)

 

We hope you all have enjoyed keeping up with us this summer! We can’t wait to see what the future holds for The Brothers and our other island neighbors.

Signing off,

~Nate & Dawson, EBI 2016

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

Metinic Depature

We’re coming to a close here on Metinic. Most of our tern chicks are flying around or landing near the water’s edge. We’ve taken down most of our productivity plots, since we can’t monitor chicks that can fly out when we get close. The guillemot chicks get closer to fledging every time we check the burrows.

Shorebirds are becoming more and more plentiful, with dozens of short-billed dowitchers and semipalmated sandpipers flitting around the north end of the island every day. Several whimbrels have taken up residence atop the hill by the gull colony and a few semipalmated plovers, least sandpipers, ruddy turnstones, and yellowlegs have been gleaning the tide line for food.

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Short-billed dowitchers use their long bills to probe deep into the seaweed

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Ruddy turnstones got their name from their habit of flipping small rocks to seek food

It’s the time of year for berries, and the island is covered in raspberry bushes in full fruit. A few early blueberries can also be found growing low to the ground. On one of our birding trips through the woods, we came across a bountiful clearing rife with raspberries. It was a great spot for a snack break.

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Snack time!

We’ll be heading back to the mainland on Tuesday. It’s been a great summer out here of monitoring birds, racking up bird species (still at 96), and chasing sheep. The weather has generally been fantastic, and the sunsets continue to be beautiful. It’s bittersweet to leave, but as the terns depart, so must we.

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Sunset from the tern colony

So long, and thanks for reading!

-Mark and Helen

Metinic 2016 Crew

Metinic 2016 crew banding an arctic tern

Living on an island

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A sunny afternoon overlooking Eastern Brothers 

As we’re adjusting to our first week back from break, we thought to talk a little bit about how it is living on a seabird island for the summer. Although checking burrows, surveying for alcids, and keeping the island predator free takes up a majority of our time, we still find time to enjoy all the coast of Maine has to offer.

One would think being stationed on a small island would become somewhat monotonous, but we find that the little things keep it lively and help pass the time. When the weather cooperates, we enjoy taking walks around the island looking for more species to put on our list, mainly migrating songbirds and shorebirds.

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Chestnut-sided warbler 

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Magnolia warbler 

However, on those foggy or rainy days (sometimes lasting for a few days), we turn to books and cooking. Dawson is a trained chef when it comes to whipping up a batch of delicious Polish pancakes.

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A pancake waiting to be flipped

We also have identified a variety of wildflowers that are dispersed throughout the island, filling in the wet meadows and the sunny hillsides.

 

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Slender Blue Flag (Iris prismatica)

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Blue Marsh Bellflower (Campanula uliginosa)

Since we’re roughly 5 miles off the mainland, the temperatures rarely rise above 70 with a constant cool ocean breeze. However, on the days where the wind dies down and the sun’s out, the ocean water (~56 degrees) is quite refreshing.

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Nate meditating in mid-air

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Dawson mid-flip and dangerously close to a belly-flop

Lastly, we always end our days, usually cleaning up from dinner and watching the sunset and the moon rise. However the day goes, it always seems to end in a beautiful sunset overlooking the Englishmen Bay.

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A glowing full moon captured with our spotting scope

~Nate & Dawson, EBI 2016

To Catch a Predator

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Armed to the teeth: by the end of our owl adventures, there were 15 padded leg-hold traps on perches stationed around the island. Not all of them worked out so well, though; the owl actually perched on the taller trap on the left without triggering it!

Most people who do bird work get into a rigidly defined schedule. More often than not, it involves waking up early– often hours before sunrise– and going to bed early to accommodate for our early-bird hours. Seabird work here on the Refuge is a bit nicer, with our day officially starting at a relaxing 7:00 am. For the past few weeks, however, the Ship Island crew has had to turn our schedule topsy-turvy, thanks to a dastardly nocturnal visitor: a great-horned owl.

Kelby first spotted the owl on an inauspicious morning in late June. We tossed up a first round of traps that very day, but the owl didn’t return for almost two weeks! When it did return, we knew it had discovered the tern colony from the number of bodies left behind. Over the next few weeks, we gradually increased nighttime monitoring, starting with midnight trap checks and escalating until we had somebody present in a blind during every single hour of the night.

Thankfully, our efforts paid off. At 12:17 am on 7/21, as I was tucking myself into bed after the 9-12 blind stint, I received a phone call from Kelby: we captured the owl!

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Handling raptors is a bit different than handling little seabirds. For one, terns don’t have knives on their feet…

Our adult and fledgeling terns face predation from various birds of prey, and not all of them are equally problematic. We have near-daily predation events from nearby nesting peregrine falcons, which accounts for dozens of casualties over the course of the season. This doesn’t seem to disturb the terns outside of the five minutes or so that the falcon is present, however. The same goes for merlin, northern harrier, and even the occasional Cooper’s hawk that finds its way out to Ship.

Terns and other seabirds have evolved a colonial defense against aerial predation, accomplished by banding together to evade capture in spectacular dread flights or by chasing off the predator altogether with brutal dive-bombing and excrement-shooting tactics. Nocturnal predation, however, is a different game altogether; the adult terns panic when they are threatened by a predator they cannot see, and will simply leave the colony for the night if they feel unsafe. If an owl is visiting for consecutive nights, fattening up on a steady diet of tern chicks and fledgelings, the adults will eventually decide not to return the next morning at all. That leaves the entire year’s worth of chicks to starve and fall victim to plundering by gulls.

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Built to kill: with long talons, powerful feet, and a toe configuration that can rotate to restrain prey, owls are well-adapted to surprise prey under the cover of darkness.

It turns out that this particular owl has been visiting more than just Ship Island for its nighttime escapades. A brief trip to Trumpet Island revealed at least five gulls recently killed, and we have heard nighttime disturbances from the birds nesting on nearby East and West Barge Islands at well. Even though we will only be able to see the positive effects of apprehending the owl here on Ship, we can rest easy knowing that the threat to the other nearby seabird colonies has been mitigated.

What happens next? Our big “friend” spent the night here on Ship but was picked up promptly the next morning. It will spend the rest of the week in a fancy flight cage with a local wildlife rehabilitator until it’s time to drive far, far inland. The owl will be released at a lush forest camp teeming with plenty of non-seabird prey, where he can live out his days hunting responsibly.

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Roger hurried out for an early-morning pickup. Here, he pushes the boat off with the owl (left) safe on board.

That’s all for now. We’ll have one last update on island news within the week. Closing is on 7/26 (!), but work will continue right until the end.

Meredith, Ship I.

Bonus bird fact: the great-horned owl’s closest North American relative is actually the striking snowy owl. While they may seem quite different at first glance, they share many morphological and ecological similarities. This even includes those striking “horns”; if you see a snowy in the right wind, you might catch a glance of its miniature ear tufts.

More tern chicks are fledging with each passing day here on Metinic!   It is great to walk out into the colony and see the chicks take off into the air rather than running to the tall grass for cover, especially after a couple of weeks of limited food coming in.  Some of the older chicks are starting to venture out into the intertidal and over the water; we even saw a fledgling way down at the very southern end of the island when we walked down there one afternoon.

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A fledgling watching us carefully.  It took off as soon as we got closer.

The chicks aren’t the only ones venturing out.  This week during a provisioning stint, Mark spotted a roseate tern resting on a rock in the intertidal!  While this tern appeared to only be passing through and not a resident, this is still exciting because they are federally endangered, and so it is nice to see that they are at least in the area.  This brings our island species list up to 96!

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The roseate tern Mark spotted on the right, and a common tern on the left.  Roseate terns have a longer bill and tail than the Arctic and common terns.  Their bill is also mostly black and their body is paler in color than the other terns.

Earlier in the week we spent an afternoon searching for Leach’s storm-petrel burrows.  Previously, we had been doing this by smelling holes along the old rock walls as the petrel burrows give off a distinct scent that is described to be like old musty books.  After reading on a previous blog that the petrels could also be found by playing their call from our phones and listening for a response from the birds, we were able to find even more burrows.  So, a big thank you to our friends on Petit Manan Island for that suggestion, it seems to work well!  If you’re curious what a Leach’s storm-petrel sounds like, here is a link to website with audio recordings of them: Click here to get to the website.  We do have petrels burrowing underneath our house, so it is funny to hear this at night and periodically during the day!

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One of the entrances to a Leach’s storm-petrel burrow along the old rock wall. 

I’ll leave you with a fun thing happened this week as I was walking along the shore back to the house from checking burrows.  I came across a plastic water bottle that looked like it had something inside it, and to my surprise, it was a message in a bottle!  It’s true that you never know what you’ll find working out on the Maine coastal islands!  I will email whoever sent it out to let them know where we found it!

 

 

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Other than our continued provisioning, productivity, and guillemot burrow checks, that’s about it for this week!

– Helen

Why band birds?

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How many chicks do you count in this nestcam still?

Hey again from Ship Island, where the summer’s swelter presses ever-onward. Since our first hatching on 6/16, the crew here has put out over 500 bands on emerging chicks, but even this is just a small fraction of the total number of young birds growing up on Ship. With an average overall clutch size of 2.35 and over 680 breeding pairs of terns, there could be over 1,600 chicks swarming Ship Island right now! …And that’s ignoring all of the non-seabird species our tiny chunk of land in Blue Hill Bay plays host to. Of course, it’s just about impossible to catch and band them all; after barely 24 hours of life, the downy chicks will start making their first forays away from the nest bowl, making them quite difficult to locate and catch.

Lately, tern wrangling hasn’t been the only bird research conducted at Ship! Last week, we had a guest researcher and technician from the University of Maine come ashore with mist nets in tow. They are pursuing an ambitious project looking at character displacement and niche partitioning in multiple populations of coastal sparrows, from generalists like song sparrow (Melospiza melodia) and Nelson’s sparrow (Ammodramus nelsonii) to specialists like the rapidly-declining saltmarsh sparrow (Ammodramus caudacutus). We had a great few days of intellectual exchange; Kelby got to learn all about passerine capture and handling, and our guests had the chance to get immersed in an aggressive common tern colony!

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We were very excited to learn that this male Nelson’s sparrow was not the only of his kind on Ship; he has a mate, and a nest that has fledged at least two young!

No matter what kind of biological research with wild bird you are conducting, be it conservation/management, behavioral ecology, population demography, migration dynamics, or otherwise, there is one core action taken with the birds that is a constant across all of these disciplines: banding the bird.

With this in mind, I thought I’d take a moment to answer the single most common question I’m asked by laypeople when doing fieldwork: “why do you band birds in the first place?

Like many questions, this one has both a short answer and a much longer answer. In its simplest form, bird banding serves one fundamental purpose: permanently mark an individual within a population.

An individual is typically marked with a federally-issued metal band that contains a unique combination of numbers (for example, most Ship Island bands this year lie somewhere between 1332-71600 and 1332-72000). Different countries issue different types of bands; here at Ship, we have resighted several common terns originally banded in Argentina. They have a totally different band format! There are hundreds of bird banding stations placed across the United States, Canada, and the neotropical wintering grounds of our many species; collaborative data collection from all of these stations gives us a detailed view of where birds are moving.

Federal bands aren’t even the only ones that you can use to mark birds; different varieties of field-readable bands allow researchers and birdwatchers alike to gather data on a bird without having to recapture it. A couple examples: the Refuge’s Arctic terns (Sterna paradisaea) receive metal field-readables with an alphanumeric code; numerous seabirds and waterfowl are labeled with colored field-readables with numbers or letters; songbirds everywhere are given colorful plastic color-bands in unique combinations to distinguish individuals.

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We were able to read this common tern’s band number from the blind using a camera, and learned that the bird was first banded on Ship Island in 1998!

These applications only brush the surface of all the research and management activities enabled by bird banding. If you think long enough about it, many more ideas spring to mind: hunters report banded ducks that they have taken; birders everywhere go out of their way to report field-readable bands; recapture data allow us to positively determine a bird’s age. The possibilities are nearly limitless, and all stem from the simple application of a small metal ring to a bird’s leg.

Back to the birds for me, now. The common terns on Ship are getting ready to fledge, and work presses ever onward.

Meredith @ Ship I.

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