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Posts Tagged ‘Maine Coastal Islands NWR’

For the third consecutive year, Maine Coastal Islands National Wildlife Refuge collaborated with partners and volunteers to band northern saw-whet owls at Petit Manan Point unit (Sept 28-Nov 6, 2016).  The Refuge has identified the peninsula of Petit Manan NWR and islands like Metinic Island as important stopover sites, especially for hatch year birds making their first migration.

Northern saw-whet owls breed in the boreal saw_whet-nathan-weyandtand northern hardwood forests of the US and Canada and migrate to lower latitudes for the winter, with the northeastern population having a cyclical increase in reproductive success and subsequent migration irruption every 4-5 years.  The autumn of 2016 was one of those “irruption” years, and was a busy one at Petit Manan Point.   The banding station operated 6 nets on 30 nights (265 hours) and captured 431 owls.  The two busiest nights for migration were October 14 and October 27, when 66 and 73 owls were caught respectively.  Nets were open daily from sunset to sunrise weather permitting, and audio lure of saw-whet calls was played to attract owls to the nets.  In addition to capturing saw-whets, 6 barred owls were banded and released at a distance away from the Point.

Barred owls are usually thought of as year-round residents, with a territory size of at least a square mile per owl.  During years when prey populations result in reproductive pulses of saw-whet owls, the same abundant prey also result in more young barred owls being produced.  These young barred owls then disperse to find vacant areas where they settle in as permanent residents.  During this autumn dispersal, barred owls are often captured at saw-whet owl banding stations, sometimes while attempting to prey on the much smaller saw-whet owl.

Year Owls Banded Foreign Recaptures Capture Rate (Owl/Hour)
2011 182 5 2.17
2014 56 0 1.49
2015 285 1 0.95
2016 431 1 1.62

 

The Petit Manan Point station is part of Project OwlNet, a continental network of more than 125 banding stations.   Several saw-whet owls banded at Petit Manan Point from 2011-2016 have been recaptured at other stations in the eastern US (Figure 1).  Saw-whets owls outfitted with small radio transmitters (nanotags) in 2014 traveled by Metinic Island and St. John, New Brunswick during migration that year.  Project OwlNet is responsible for much of what is known about saw-whet migration routes and timing.

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Volunteers and partners make this project successful!  Dave Brinker, of Maryland DNR and the founder of Project OwlNet (www.projectowlnet.org), initiated the current Petit Manan Point station in 2014.  Adrienne Leppold of Maine Dept. of Inland Fisheries and Wildlife is the co-director of the Petit Manan saw-whet owl netting effort.  Adrienne assists with all local details of station operation throughout the owl season.  Each autumn, Dave comes up to Maine to set up the station and get it operational while training a volunteer bander that will be on site all season.

In 2016, Dave recruited volunteer Nate Weyandt to run the station.  Nate is from Latrobe, PA and just worked a greater sage-grouse research project in Utah.  His main hobbies include fishing and bird banding.  This was the first year he captured owls and thoroughly enjoyed it, especially because they are difficult to see in the wild otherwise.  Nate was joined by volunteers Ed Conrad and Caroline Jordan for the last 3 weeks of the season after operating a passerine migration banding station at the Schoodic Institute.  Ed banded saw-whet owls on the Refuge in 2011, when we first documented the importance of the Petit Manan peninsula to bird during migration.  We now hope to establish a permanent migration station at Petit Manan Point.  In 2016, 27 volunteers contributed a total of 750 hours to this project.

Thanks to the generosity of the Friends of Maine Coastal Islands NWR, the banding crew had a wonderful house to stay in after long nights of banding.  The Wehr family donated the house to the Friends group, and who will soon transfer the property to the Refuge.  The Wehr house was an immense improvement to living in the cramped banding station travel trailer with no running water.  Without the Wehr house, it would have been very difficult to attract volunteers for an extended amount of time.  Thanks so much to all of the Friends, volunteers, and partners for making this season possible!

 

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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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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

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