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Archive for the ‘Ship Island 2016’ Category

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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.

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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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The first common tern egg of (hopefully) many.

It seems as though Wednesdays are the most eventful days here on Ship Island. Last Wednesday  was spent scouring the island for Garlic Mustard plants. This Wednesday was a whirlwind of events. Not only did we find our very first tern nest but it also contained our first egg! Along with that our island supervisor Meredith spotted a roseate tern while we were sitting in the blinds.

Aside from this tern excitement we had two seal encounters right on the shores of our island! I found this so exciting because usually when observing the seals we must do so with a spotting scope to see them on the East and West Barges. However during our blind observation on Wednesday we had an adult seal haul out on to our beach and spend a little time sunning itself.

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Adult western Atlantic harbor seal on Ship Island tern beach (P. vitulina concolor)

In our area we have two species of seals, western Atlantic harbor seals, and grey seals. The best way to tell them apart is by looking at their heads. Harbor seals have more of a smaller dog nose with not much of a neck and grey seals have larger ‘horse like’ faces and a more pronounced neck. The seals I’ve most often observed were the western Atlantic harbor seals on East Barge. This is also what we had come visit us Wednesday morning.        Later in the day when all the work around the island is complete is when  I enjoy observing our seals– mainly because right now is their peak pupping time (mid May to July), so we seem to have new pups arriving everyday. On this ever so faithful Wednesday evening I got the privilege of observing a very new harbor seal mom with her pup (I could tell he had just been born as some of the birthing organs were still attached).

What surprised me most though was this new mother promptly lead her new pup into the ocean. This is surprising because everything I’ve read about harbor seals says the pups can’t swim till at least an hour after birth, and here this moms bringing her pup in minutes after birth. Almost immediately after entering the water our new mom brought her pup further into the water (toward Ship I.). This was in order to bring her pup further away from the other seals. So I packed up my things and headed back to the cabin assuming the days excitement was over. Upon returning to the cabin I saw that Meredith had left on a photography adventure. A few minutes after that I received a text from stating there was a pup on our shore. Sprinting to meet her, she showed me what she had found: sure enough sitting atop the seaweed was a pup.

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Newborn western Atlantic harbor seal pup on back side of Ship Island (P.vitulina concolor)

Shortly after looking at the pup longer, and seeing a small piece of umbilical cord, I realized this was the seal pup I had been watching only 20 minutes prior. Meredith and I proceeded to sneak away as not to scare off the mother wherever she may be. Most of the time mothers don’t leave their pups because they need to be together for 4-6 weeks so the pup can nurse. Pups can also be vulnerable to some predators. After dinner Meredith and I went along the islands edge to check up on our young visitor. What we found was his mother hauling out of the ocean to retrieve her new baby. We quickly snuck away so we didn’t disturb them, thus ending another successful Wednesday on Ship Island.

Till next week,

Kelby Leary                                                                                                                                                           Ship Island Crew Member

 

 

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