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Posts Tagged ‘Petit Manan Island’

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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Petit Manan Island is well known for its seabird inhabitants, most notably our Atlantic Puffins and Arctic Terns. However, a total of eight species of marine birds return yearly to nest on Petit Manan Island. Most of these birds have conspicuous nests, such as the terns and Laughing Gulls which lay their eggs on the ground’s surface. The Alcids, such as Puffins, Black Guillemots, and Razorbills, lay their eggs in burrows or rock crevices, but the adults are still easily observed on the rocks and surrounding waters. But Leach’s Storm-Petrels, the smallest seabird denizen of Petit Manan, are a little bit trickier to detect.

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Jimmy holding an adult Leach’s Storm Petrel that was grubbed from a nearby burrow

Leach’s Storm-Petrels differ from the other seabirds on PMI in a variety of ways. Taxonomically, they are the only species representing a group of seabirds called the Tubenoses to be found on PMI. Also, they are nocturnal and nest in often long, twisting sod burrows.  The burrow entrances are smaller than the size of a fist, and tucked underneath rotting logs, debris and rocks. These life history traits make observing storm-petrels quite the challenge, and prevent accurate estimations of breeding pairs on nesting islands.

This summer we have been testing a new methodology to s
urvey for active storm-petrel burrows. Instead of just reaching as far into each burrow to feel for birds and eggs, we have been playing a recording of storm-petrel vocalizations outside of each potential burrow entrance. The results have been extremely exciting! The birds have been responding with their strange, goblin-giggling call from deep within their burrows. But more importantly, this method has allowed us to find more birds than just by feeling in the burrows. In fact, 63% of the storm-petrels we located only because we heard them – their burrows did not allow us to reach them. Overall, 93% of the adults we located using both methods responded to playback. Hopefully this monitoring technique will provide new insights into Leach’s Storm Petrels nesting on Maine coastal islands!

-Jill

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While most of the other MCINWR islands are winding down for the season, Petit Manan is still going strong with major alcid trapping, island-wide guillemot and storm petrel checks, Arctic tern re-sighting, and our new-this-year project: Atlantic puffin feeding studies.

Atlantic Puffin with bill load

Atlantic Puffin with bill load through scope.

Puffin flying to burrow with fish that we have to identify as part of our feeding study

Puffin flying to burrow with fish that we have to identify as part of our feeding study

During our alcid checks, we discovered two little surprises in the form of Razorbill chicks! Only five pairs are breeding here on Petit Manan, so each new chick is very special to us. We even managed to capture one of his parents bringing food back to the burrow, an unusual sight here on PMI

Freshly banded Razorbill chick

Freshly banded Razorbill chick

Razorbill flying with food

Razorbill flying with food

Here are a few more snapshots of what else has been going on at PMI.

Black Guillemot chick being weighed during our weekly productivity checks

Black Guillemot chick being weighed every 5 days as part of our productivity checks

Leach's storm-petrel chick

Leach’s storm-petrel chick

PMI crew banding a puffin chick, minus Julia who took the photo

PMI crew banding a puffin chick, minus Julia who took the photo

A puffin undergoing the banding process

A puffin undergoing the banding process

Wayne and Julia with their first captured adult Razorbill!

Wayne and Julia with their first captured adult Razorbill!

Until next time,

Wayne and Julia

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Last week, John and I trapped and banded our first terns! We were thrilled to finally have the opportunity to see and work with these birds up close. But these amazing up close interactions did not come without a lot of hard work and preparation.  The process of trapping and banding is very detailed and a complete understanding is needed to keep the terns happy and healthy.

Before we could start banding, Julia and Wayne had us practice on dummy birds. These dummy birds were composed of cardboard toilet paper rolls for bodies, Q-tips for legs, and duct tape for heads. Julia and Wayne informed us of the methods of handling and banding terns when out in the field and with their help we simulated banding on our dummy birds by using old bands. After we felt comfortable with banding we learned how to collected measurements from our birds. When a tern is captured we recorded the weight, wing length, and head and bill length of the tern. We got to see and use all of the tools used to take these measurements.IMG_8528

In preparation for trapping, we laid out all of our equipment out on the lawn and checked to make sure all of the traps had all their components and were functional.  John and I spent some time getting used to setting up the traps and gripping the idea of the little quirks that makes the trapping process run a lot smoother.  Once we were quick and efficient with setting up out traps we were ready for the real deal!

Laura & Julia setting up their trap

Laura & Julia setting up their trap

Our first trapping day was nerve racking and exciting! We had to find a balance when trapping and banding our terns that would enable us to work fast but also be gentle and thoughtful when handing the terns. As much as we wanted to take our time and soak up all the beauty, we had to act quickly and efficiently when banding the terns to minimize the amount of stress placed on the birds. I felt uneasy going into my fist banding experience; this wasn’t like the dummy birds we practiced on, the terns move around a lot more than the dummies and one wrong pinch on the band could harm the tern. But to my surprise banding my fist bird came natural to me and it went smoothly. I got to trap and band many more terns that day and I hope to do some more in the next few days.

John and his tern

John and his tern

So far we have trapped 19 COTE (common terns) and 16 ARTE (arctic terns) our goal is to have a total of 20 COTE and 100 ARTE by next week! Trapping and banding terns is important because it shows sight fidelity and survival rates of juveniles and adults.

– Laura Bollert

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In my last blog I mentioned that the Petit Manan crew had resighted a banded American Oystercatcher (AMOY) with its mate on Green Island which is adjacent to PMI and only accessible during low tide. After observing the banded AMOY in mid-May, we submitted our finding to the Bird Banding Lab website and received information about the bird. We discovered that it was born and banded as a chick in 2006 on Nantucket Island, Nantucket, MA. It was last resighted in 2014 in Charleston, South Carolina,

Observing American Oystercatcher on Green Island. Photo by: John Fatula

Observing American Oystercatchers on Green Island. Photo by: John Fatula

On our second visit over to Green Island we were combing the north-west side for any sign of Oystercatcher eggs, when we noticed that our 9 year-old banded AMOY, with its mate, were unusually vocal. So, we decided to move out of the area and use a spotting scope to watch from a distance. After about 15 minutes of scanning around we noticed tiny little chick heads in the rocks and sure enough they were 3 oystercatcher chicks!  We all watched through the scope as the adults foraged around and were surprised how quickly the adults can extract the meat from a mussel and feed the chicks (about 3 seconds). AMOY chicks will usually stay with the adults for up to a year to perfect their foraging techniques.

Foraging AMOY with 2 chicks( you can see how camouflaged the chicks are.)

Foraging AMOY with 2 chicks: you can see how    camouflaged the chicks are.

Banded AMOY with chicks. Photo by: Julia Gillis

Banded AMOY foraging with chick. Photo by: Julia Gillis

After further research by Linda Welch we were informed that these were the first AMOY chicks to be discovered on Green Island since 1997! Not only that, they have now become the most northerly breeding pair within their range. How cool! We always thought that Green Island seemed like a perfect place for AMOYs to nest, and have seen them loafing there in recent years, but never found any eggs or chicks as the adults are very secretive.  With just a few alarm calls by the adults, the chicks instinctively hide deep in the rocks of the intertidal zone. Each adult will constantly call and try to lure any predators out of the area. We just hope this pair can keep the prying eyes of the gulls away from discovering their chicks so they can grow up and successfully fledge. And we even received a certificate for our efforts.

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-Wayne

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Snowy owl!?  Yes PMI had a snowy owl preying on Atlantic puffins and Black guillemots.  It was first spotted flying from Puffin Point and hunting all around the alcid colony. After several days and numerous attempts to discourage it from the island with pyrotechnics, we finally had to take action by setting out soft-coated leg-hold traps to try and capture the owl without injuring it and then relocating it. Now, placing the four traps that we had would be tricky as this particular owl didn’t perch or roost in any one spot twice. So I figure if it likes puffins so much the best way would be to dig out this old Puffin decoy I found stashed in our tool shed and put him to good use. We set up the traps and decoy just on the edge of the alcid colony at sunset just far enough so no alcids would fall into our traps.

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Puffy the decoy working hard on the job

The next morning “Puffy” the puffin decoy did his job! Two traps were set off and Puffy had his first battle talon scar on his chest! After that morning the Snowy owl was never seen on the island as of this posting which has been over 3 weeks! So now with this peculiar predator off the island our resident birds can get back to doing their thing, which is…..

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Guillemots mating

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Puffins mating in the water!

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Razorbills Mating on Puffin Point

Arctic Terns Mating

Arctic Terns Mating

Common Terns Mating

Common Terns Mating

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Even species that we don’t like to encourage have started mating now that the snowy owl is gone!

 

– Wayne

 

 

 

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In the last few days we began our island wide Alcid (puffins, guillemots and razorbills) monitoring. This means we get a look at our first puffin and razorbill chicks! At the beginning of the season we searched within the rocks, ledges and debris around the edge of the island for burrows of Alcids. After marking their nests, we planned to return once the chicks hatched.

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(above: Jill with a razorbill chick)

Alcids are burrow nesters, meaning they lay their eggs inside a tunnel or crack in the rocks or soil. This keeps the eggs and chicks safe from most predators and also keeps the temperature for incubation fairly steady. Puffins and razorbills put all their eggs in one basket (so to speak) and lay only one egg in their burrows, while guillemots lay two. It’s interesting to note that guillemot eggs and razorbill eggs are speckled white and puffin eggs are solid white. I wonder why that is?

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(above: Jill with a Puffin chick)

Alcids are burrow nesters, meaning they lay their eggs inside a tunnel or crack in the rocks or soil. This keeps the eggs and chicks safe from most predators and also keeps the temperature for incubation fairly steady. Puffins and razorbills put all their eggs in one basket (so to speak) and lay only one egg in their burrows, while guillemots lay two. It’s interesting to note that guillemot eggs and razorbill eggs are speckled white and puffin eggs are solid white. I wonder why that is?

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While we were checking alcid burrows Jordan came across a beautiful find. A leach’s storm-petrel! (see above photo) These strange pelagic seabirds nest throughout Petit Manan in burrows dug into the soil and sod. At night we can hear their strange calls that sound a lot like giggling. They are truly mysterious and beautiful creatures!

With the season coming to a close we are saying goodbye to our field tech and friend Andrea. It’s been a great summer with all four of us here and we are sad to see her go. Andrea will be getting back to school this fall at Umaine where she is studying Zoology with a focus on seabirds. Good luck Andrea!

 

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