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Posts Tagged ‘Common Tern’

This past week on Ship has been very similar to what has been going on at Metinic and PMI. Most of our days have been pretty dreary. On these foggy and rainy days we spend our time reading (A+ to Morgan for reading 8 books so far), eating snacks, catching up on sleep, writing letters, drawing, and staying updated on what’s going on in the real world. It is relaxing, but we’re anxious to get back out there and get a closer look on how our terns our doing.

When it’s not too foggy out, we are able to sit outside and watch the colony. We don’t sit too close because we don’t want to surprise or scare them. We’ve been doing this frequently to deter the Peregrine Falcon who has been stopping by from the island.

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Sunset view while watching for predators

Before the bad weather, we spent most days attempting to re-sight bands, making productivity plots, and trapping adult terns to band, measure, and weigh. To trap the terns we use a Treadle Trap. We first need to replace the eggs with fake eggs. This prevents the tern from damaging their eggs once he/she is trapped. After this we place a wired box over the nest with one end open. When the bird steps through the opening onto the pad, the door will shut and the tern is unable to escape. We quickly retrieve the bird to collect our data, put back the original eggs, set him free, and repeat. It was pretty cool when I got to hold and release my first tern!

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One of our productivity plots

The results from our GOMSWG census indicated that we have about 620 nests in total. Hopefully we’ll start seeing some chicks soon!

-Amanda

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This weekend the Ship Island crew headed over to Pond Island to take part in a beach cleanup along the shore. Morgan and I, as well as several other volunteers, collected dozens of trash bags filled with lost buoys, cans, bottles, and more. This year is the first year the group will be able to actually recycle the plastic that was collected. Through the company, TerraCycle, our collection of plastics, no matter how dirty or broken they may seem, will be sent over to be thoroughly cleaned and re-purposed. Typically, most objects made out of recycled plastic only consist of about 30% reused material. Though it doesn’t seem like a lot, or maybe even not enough, if the concentration is increased then the new object becomes closer to the end of its lifespan and can no longer be reused. It was good to get off the island and spend some time with others working to keep our environment clean, but we’re glad to be back on Ship with our terns!

 

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Section of a boat that was found washed to shore. We needed all hands on deck to carry this one over!

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Beach Cleanup Volunteers

Back home on Ship, we’ve had problems with other birds predating on our Common Terns and their eggs. Currently, Great Black-backed Gulls, Herring Gulls, American Crows, Peregrine Falcons, and Northern Harriers are our main concerns. Almost every day we spend two hour shifts in the blinds to observe the tern behavior and keep an eye out for any of these predators that might pass by. During the evening we’ve been marking nests with predation sticks so we can notice if any eggs have gone missing. By doing this we are also able to get a good idea on how many terns we really have on the island. It doesn’t look like it, but so far we have counted over 500 nests, which means we have over 1000 terns! So far so good! In a few days we will be doing a GOMSWG census which will give us an even closer estimate on our tern population size. We’re excited to share the results with you next week!

-Amanda

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Petit Manan Island is in peak hatching season! The small, delicately speckled brown tern eggs are disappearing and being replaced by similarly patterned fluffy chicks. The oblong, white-brown spotted black guillemot eggs are opening up to reveal all-black downy chicks. Where once we were seeing large, gleaming white puffin eggs, now chicks with long grey down and white bellies are hiding quietly in their burrows. We even have found one razorbill chick (see photo below)! The only seabird still solely in the incubation stage are the Leach’s storm-petrels.

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One question that I often get asked is, why do some seabirds only ever hatch one chick (think puffins, razorbills, storm-petrels), while others can rear multiple chicks (terns, guillemots, etc)?

In general, seabirds have small clutch sizes compared to birds of other groups like most waterfowl, game birds, and some perching birds. This is because seabirds, unlike the groups mentioned previously, tend to have long life spans. This means it is not quite as critical for seabirds to have a successful nesting season their first breeding season or every year of their life in order to replace themselves in the population. Other bird species may only get one chance to successfully reproduce if annual adult survival is low due to high depredation of adults and/or other factors.

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But why lay only one egg instead of two or even three? There are multiple factors that influence seabird clutch size, and still many questions to be answered. Chick rearing is very energetically demanding for the parents, from egg formation to providing enough food for growing chicks. Right from when birds arrive on the breeding grounds, food availability is critical. After long migrations or rough winters, seabirds need to be able to find enough resources near their breeding colony to allow them to be in proper condition for breeding. Limited food resources during this period of time can cause birds to lay smaller clutch sizes, or even not nest at all.

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This still does not answer our question why puffins and other species only lay one egg, in both good and bad food years. For species with one egg clutches, it is more beneficial for the long-term survival and breeding success of the adults to raise only one chick at a time. Raising two chicks would probably not be impossible during good food years, but the energetic costs on the parents might make this not worthwhile in the long run. So puffins, razorbills, and many other seabirds prefer to take things slow, laying only one egg per season.

Currently, we have found 17 black guillemot chicks, 15 Atlantic puffin chicks, one razorbill chick, and a few hundred tern chicks!

-Jill

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The beginning of the week started out slow and rough as the weather was not cooperative.  High winds made it so we could not go out to the tern colony as we wanted the adults to stay on their eggs and keep them warm from the howling winds.  Finally the weather broke Tuesday afternoon and we were able to do some trapping and banding of adult terns.  We do this by selecting a couple of nests, replacing the eggs with wooden ones so they do not get damaged, and placing a chicken wire trap over the nest with the door open.  When the adult walks into the trap, they step on a trigger platform that closes the door.  As the adult sits in the trap incubating the wooden eggs, we walk up and take it out of the trap through a hole in the top.  The adult is then placed in a bag where it is weighed using a spring scale.  We then band the bird and measure its wing chord and head-bill length before it is released to return to incubate its eggs which we have switched back to the real ones.

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A common tern checking out the trap

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Measuring wing chord length

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Measuring head-bill length

Wednesday we headed over to Matinicus Rock to help them with their tern census.  It was nice to get out to another island to see what was going on there; plus we got to see Atlantic puffins, razorbills, and common murres, three species that do not nest on Metinic.

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Atlantic puffins on Matinicus Rock

The next day it was our turn to census!  With the help of a few guests, we were able to count 608 nests in our colony of arctic and common terns!  We did this just in the nick of time as we came across multiple hatched chicks with more popping up every day!  The rest of the week was spent securing our productivity plots which are circles of fencing surrounding a number of nests.  When the chicks within the plots hatch, we record the hatch date and band them.  Every time we visit the plots, we weigh the chicks and keep track of how they are doing until they fledge.

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Pipping arctic tern egg

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A hungry chick waits to be fed

Throughout the week we have also come across savannah sparrow chicks and fledglings, and spotted sandpiper chicks running around on the rocks.  An identifying characteristic of spotted sandpipers is they bob their rump up and down as they walk; it is funny to watch the tiny fuzzy chicks do this as well!  We are looking forward to more chicks showing up in the upcoming weeks!

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A tiny spotted sandpiper chick

Until next week,

Helen

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COTE gettin trapped

An unsuspecting common tern parent walks calmly into a trap to incubate a clutch of wooden dummy eggs.

As the summer starts to pick up so does the tern activity here on Ship. At the end of last week we had some visitors from the Student Conservation Association  come to help us put up new productivity plots before our island is overrun with new tern chicks. The productivity plots contain 6-11 nests of varying sizes in different areas throughout the colony. These are put up so that when the chicks hatch we will be able to monitor their growth for the rest of the season. As of today we have a total of 6 productivity plots!

 

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Adult common tern  in one of the productivity plots.

This week we’ve also been trapping adult terns for banding and or recapturing. This is done by swapping out the eggs in nest with fake wooden eggs (we don’t want a parent to accidentally break their own eggs). We then place a wire treadle trap over the nest and set the trap. To set the trap we stick a wire attached to the treadle into the sliding door. Then we go hide (usually in one of our blinds) so the terns don’t see us, but so we can also see the trap. You can tell if the terns can see you because they will give you dirty looks and yell a lot.  From there its a waiting game. Some trapping stints were more successful than others, just like some birds were more cooperative than others.

COTE release

After banding, the tern is released to resume tending its nest– now with the real eggs safely back in the nest bowl!

 

Wednesday was the Gulf of Maine Seabird Working Group (GOMSWG) census day and our friends from the Student Conservation Association came to assist us in that as well. It was a successful census and a gorgeous day to do it on. During the census we also had a visit from a peregrine that we’ve been seeing on a regular basis. It came earlier this week and hung out on the back of our island. The peregrine allowed us to get fairly close, which was when we noticed it was pretty badly injured. Even though peregrines are a predator of common terns we hope it is able to recover.

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The peregrine falcon (Falco peregrinus) is a listed as an endangered species in Maine.

Finally one of the most exciting things began to happen yesterday as were putting up our last productivity plot. Yes that’s right, you’ve probably guessed it, its what we’ve all been waiting for. WE HAVE TERN CHICKS!! Two chicks hatched while we were putting up the final plot yesterday. This morning during our nest checks we found four more healthy chicks that were fully fluffed out and we were even able to band them!

We hope to have even more babies running around our island within the next few days!

Till next week.

Kelby Leary @ Ship Island

 

 

 

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hoppin on

A banded common tern (Sterna hirundo) returns to the nest for incubation. This image was remote-triggered on a hidden camera, toward which the terns are very tolerant!

Common tern activity levels on Ship have made an about-face, going from mostly quiet to positively booming! For the past 10 days or so, the birds have been active virtually all day long, courting their partners and tending their nests. At the time of writing, well over 150 nests have been established on the island. Of 100 nests being monitored for early-season predation, only 4 have been lost– and 3 of the 4 were taken out by the highest tide of the month. If you’re more of a visual learner, check out the figure below; a legend is available by rolling your mouse over the chart. If you want, you can even click to zoom in on any of the images.

In simple terms: things are going well. Breeding savannah and song sparrows have begun to hatch, as have the common eiders, gulls, and double-crested cormorants on our neighboring islands. It should be a matter of days before our nesting spotted sandpiper fathers will escort their chicks to safe foraging, as well.

 

Between seal pups, tern eggs, and the numerous fuzzy chicks emerging all around us, we have plenty to observe at Ship. Later this week we hope to establish our productivity plots for the season and begin adult trapping efforts in order to band new birds recapture known individuals. Our projected first hatch date is June 19th, so knock on wood and stay posted for the big news in a couple of weeks!

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A fuzzy creche of six common eider (Somateria molissima) chicks escorted by two hens! We hopefully theorize that the small number of adult birds escorting this creche is due to rampant nesting success of all the other eider hens out there on Trumpet and East Barge Islands.

As if all these babies weren’t enough, spring migration somehow persists on Ship. Our long-awaited Nelson’s sparrow (easily identified by its song, which sounds remarkably like a match being lit) has finally taken up residence on the island, along with an alder flycatcher that can be heard singing daily; the vocalization (a burry “fee-beeoh!”) of this bird is just about the only thing that sets it apart from its doppelganger, the willow flycatcher.

 

In birding parlance, focusing in on a single area to frequently document its species is known as “working a patch”, and that’s certainly what every Maine Coastal Islands seabird crew does. Because a daily birdwalk is part of our essential duties, we become very familiar with what species to expect on a daily basis and can quickly recognize oddities. In working our teensy patch called Ship Island, we have managed to document some 68 birds, including such bizarre wintertime lingerers as long-tailed duck, Bonaparte’s gull, and even a single black-legged kittiwake! And that isn’t even mentioning all of the freshly-molted warblers that continue to stream through in their alternate plumage.

That’s the news from Ship Island this week. Hopefully our industrious tern colony will continue to grow despite gloomy weather! In the meantime, we’ll be counting birds and huddling in the warmth of our tiny cabin when it gets too miserable out.

 

Bonus bird fact: did you know that the scientific name of the common eiderSomateria  molissima, literally translates to “very soft woolbody”? An apt name, considering how the seaducks are prized for their luscious down! And if you’ve ever had the pleasure of feeling an eider’s feathers, you’ll know this to be true.

 

Until next time!

Meredith Miles @ Ship Island

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This week Petit Manan welcomes the remainder of our crew- Shelby and Jimmy! And with them they brought nesting terns and beautiful weather!

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The view from the top of Petit Manan Light. We keep track of Alcid populations by counting them from the top of the Light twice a day!

As our second week on Petit Manan comes to a close, we have given up our reign of the island to the birds. No longer can we go to the outhouse in the middle of the night without hearing the territorial “ka-ka-ka” of Common Terns before they swoop towards our heads. Where once we could walk freely there are now hidden nests and incubating mothers that we must be careful not to disturb. And we couldn’t be more excited!

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One of four Common Eider nests we have found this week. Many more Eiders nest on neighboring Green Island.

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While searching for red-backed salamanders, I found this year’s first Savannah Sparrow’s nest hiding under a rotting log!

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And finally the one we’ve all been waiting for… the first tern egg of the season! Since then we have found three more nests, but without the safety in numbers of the whole colony nesting, these terns may have abandoned their egg so not to be targeted by Peregrine Falcons.

We hope to have another Egg-cellent week, as next we begin checking rock crevices and artificial burrows for Atlantic Puffin, Razorbill, and Black Guillemot eggs!

Until next time here is a bit of wisdom, “I value my garden more for being full of blackbirds than of cherries, and very frankly give them fruit for their songs.” -Joseph Addison

Best,

Morgan

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Petit Manan Seabird Researchers 2016 – Shelby, Jimmy, Jill, & Morgan

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