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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.

Although the majority of the first half of our field season has been nothing but blue skies and sunshine, this past week has given us enough rain for the whole summer. However, the terns and guillemots don’t seem to mind much. They’re growing more and more everyday; the terns chicks from nest # 2 already have most of their primaries in! While the guillemots may not be as further developed as the terns are, we’re finding at least a dozen new chicks every time we check the burrows; we almost have as many chicks as we have burrows (67 chicks and 73 burrows!).

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Dawson checking out the wings of a healthy black guillemot chick.

Now that we have all of our tern chicks hatched (8 in all), we have started our provisioning surveys. These are conducted 4 times a week for 3-hour stints at a time, recording the species of fish that the adults bring in to feed the chicks. The most common fish that are being brought in are sandlance and herring.

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Healthy “A” and “B” tern chicks from nest # 3.

We’re also beginning to see a wide variety of early migrants on the island, from shorebirds to raptors. Notable sightings include: spotted sandpiper, killdeer, semipalmated sandpiper and northern harrier. We’re adding more species to our running list everyday, with the northern harrier making it 43. The upcoming week is our break off the island, and we plan to do a lot of hiking and exploring around the area, taking advantage of the sun coming our way. We’re excited to see how much our chicks grow when we get back!

~Nate and Dawson, EBI 2016

 

Fledging in the Rain

We’ve got tern fledglings on Metinic! After a few breezy days of large chicks jumping up and flapping, some have finally gotten airborne. While not as sleek or acrobatic as their parents, the somewhat pudgy fledglings are still capable fliers. They are still returning to their nests to get fed, but then fly off instead of running into the grass with the smaller chicks. Even as our first chicks take to the air, more chicks keep hatching, so we’ll continue to be busy for the next few weeks.

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These arctic tern chicks are from nests 5 feet apart. One is ~18 days old, the other ~3 days old. Arctic terns fledge at around 21-24 days.

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An arctic tern flies in with a small hake for a small chick.

As if to make up for the splendid weather we’ve had most of the season, the dreary fog and rain has finally been keeping us inside. It’s best to keep off the tern colony when it is cool and wet so the parents can keep their chicks warm and dry instead of flying at us. The weather has given us a good opportunity to catch up on data entry and stay warm around the wood stove, at least whenever we aren’t heading off persistent colony-bound sheep.

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The wood stove is a welcome sight upon returning from chasing sheep in the rain.

During breaks in the dismal weather, we’ve gotten out to check on our growing guillemot chicks. They’re starting to get pretty big and hiding deep enough in their burrows that it has become a bit of a challenge to get some of them out to weigh them and measure their wing chord. While wedged in the rocks with my arm deep inside an active guillemot burrow, I spotted our first whimbrels of the season on the beach. That brings our island species list up to 95 with a passing puffin spotted during provisioning. We’re hoping to reach 100 species before the end of the season, and it certainly seems within reach.

Until next time!

-Mark

The Chicks are Here!

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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Hello everyone!  The main focus on Metinic this week was our chick provisioning watches.  Essentially what happens is we are watching to see what the adults are feeding their chicks.  To set this up, we select a number of nests in good visibility from our blinds and mark them with numbered and color-coded tongue depressors. We then find the chicks that belong to each nest, band them, and then color a specific part of their body according to the hatch order and corresponding nest.  The first chick to hatch is called the “A” chick and is colored on top of its head.  The second chick to hatch is called the “B” chick and receives color on its chest.  The third chick to hatch is called the “C” chick and is colored on its back.

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One of our provisioning nests.  The color on top of the “A” chick’s head corresponds to the color on the tongue depressor.  When the egg hatches, the “B” chick will get the same color on its chest.

During each provisioning stint we watch each nest for adults coming in with food for the chicks.  We record the nest number, the arrival time of the adult, which chick receives the food, the departure time of the adult, the number of prey items, and the species of prey brought in and its size.  Prey size is determined based on the bird’s bill length.  For example, a fish can be recorded as 1 bill length or 1.5 bill lengths; size is measured to the closest quarter of a bill length.  All of this is often determined within a few seconds as the adults swoop in and the chicks gobble down the food quickly.  Each provisioning stint lasts 3 hours and we try to total at least 12 hours a week each.  All of this information will give us an idea of the amount of food coming in and its quality.

Besides the provisioning watches, we have also been continuing our productivity monitoring.  It is amazing to see just how quickly our chicks are growing up!  Right now the majority of them are in the process of replacing their downy fluff with feathers.  Another interesting thing to observe is the range in development.  A few of the chicks have mostly feathers and seem like they will be fledging soon, while others haven’t even hatched yet!

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One of the older chicks in our productivity plots showing off its feathers.  It is getting so big!

Provisioning and productivity take up the majority of the week, but Mark and I decided to take one afternoon to head down to the southern end of the island to see if we could spot any new species to add to our island list.  As we were walking along one of the southern cobble beaches we came across a bird washed up on shore.  At first glance it looked like a small gull, but as we got a closer look we discovered that is was a tubenose.  Upon further observation and investigation, we were able to ID it as a Northern fulmar!  Our species list is now up to 92 with the addition of a great cormorant, lesser yellowlegs, and a semipalmated plover!

That’s about it for this week, we will be celebrating the 4th of July with our seabirds!  So far, we have been enjoying the various firework shows going on miles across the water on the mainland, and who knows, we may even break out the small grill this evening!

Have a happy 4th of July!

Helen

Guillemot Chicks

Hello from the island!

This past week has been by far the most exciting and most busy we’ve had yet. Black guillemot chicks have started to hatch, finding new ones every time we conduct our burrow checks. Every three days, we check one half of the island for our marked burrows, looking for the presence of eggs or newly hatched chicks. If there are chicks present, we have to fish them out of their burrows (sometimes when the mom is in with them!) and take measurements. The first measurement taken is weight, and for that we have a special scale in which we clip a “bird bag” (fancy term for a small drawstring cloth bag) to a cylinder scale and record its weight on how far the indicator goes. The newly hatched chicks only weigh roughly 30 grams, but don’t let that fool you; we came back to a chick just three days later and it nearly tripled in weight! The next measurement we take is wing chord, or the length from the most prominent point of the wrist joint to the most prominent point of the longest primary feather. This is taken using a special ruler, but it’s easy enough to record. After the measurements are taken, and if the chick is big enough, we place a size four US Fish and Wildlife Service metal band on its right leg using a pair of modified pliers specifically made for banding birds. The bands don’t interfere at all with any of the birds daily functions, and makes it rather easy to identify the specific bird from exactly what burrow and what year it was found if it were to be captured or re-sighted in the future.

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Dawson holding his 1st banded black guillemot chick on Western Brothers.

Our tern chicks have also grown considerably since our last post, more than tripling their weight and starting to get their primary feathers! But that’s not the half of it, we have five more healthy chicks! They are all very well fed by their parents, who really don’t care for us handling their babies, constantly diving and pecking our heads (and pooping on us if we’re lucky). However, the chicks don’t make it very easy for us to find them; they often hide in the vegetation around the nest and blend in rather well, so searching for them is a very careful and mindful process. When we do find them, they get weighed the same way the guillemots do but do not get their wing chord recorded, simply due to the fact that it would be impossible for all the other islands to record that much data- there’s only 7 terns for us to measure, compared to Petit Manan with over 1,000 breeding pairs! (with an average of three eggs per nest, you can imagine why!)

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The “C” chick in nest # 1 posing for the camera.

As our chicks are growing more each day, there’s always someone that wouldn’t mind snacking on them, and here at Eastern Brothers that’s our new visitor: the peregrine falcon. We first were confused  when woken up by the terns going crazy on Saturday morning, chipping and calling from one of the ravines. We weren’t quite sure what they were on about, but after getting to one of our morning survey points, we found a dead adult black guillemot predated on by the falcon.

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The peregrine falcon perched on Eastern Brothers Island in a ravine close to the alcid decoys.

We observed it flying from island to island with the terns fearlessly dive bombing it the whole way until it eventually left. We’ve seen it two other days after that, but it has been driven off the island quicker and quicker each time with no additional signs of predation. We’re hopeful that the terns keep on driving it away until eventually it moves on.

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A black guillemot chick we found with a fish caught and drying on its bill! A rather odd sight, but we later safely removed it so it wouldn’t interfere with feeding.

Until next week,

~Nate and Dawson, EBI 2016

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