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Archive for July, 2012

Alfonso and Bernadette ready to leave their burrow any day now.

For seabirds in the Gulf of Maine, or at least for the researchers who work with them, the coming of August brings the end of another season and another summer. While you may be enjoying the beach or floating in your pool at home, seabirds are going through one of the most important events of the summer: the fledging of their chicks. For months now these parent birds have invested enormous amounts of time and energy into raising young and passing on their genes, and now is when all of that expenditure culminates, hopefully, into wonderful success when the chicks are finally old enough to leave the nest. For most birds, “fledging” technically refers to the age when chicks are old enough to fly, and for guillemots this means the chicks are at least 33 days old.

Flight feathers of a juvenile guillemot

That means their parents have been feeding and looking after their growing chicks for over a month now – not to mention the month of incubation before they even hatched – the parents themselves have lost weight from the strain of raising young while their chicks have demanded ever more from them.  On July 27 and 28 Eastern Brother’s Island celebrated its first fledged chicks of the season, Alfonso and Bernadette. They no longer resemble their smaller, fuzzy black peers but have donned a beautifully speckled black and white plumage that will aid them as juveniles at sea.

Alfonso’s beautiful juvenile plumage

Unlike their relatives, the razorbill, guillemot chicks fledge independently, usually at night, when they leave the comfort of their granite burrows and fly/hop down to the water’s edge.  Once in the water, they can dive immediately and begin to forage and fend for themselves. They float alone on the ocean for their first winter, going where the currents carry them, learning the ropes of how to be an adult seabird.  A fledged chick means a successful parent (and a happy researcher); now the fate of their young is out of our hands and rests in the hands of the Ocean. We wish you well, little guillemots!

– Julia

If only they knew we were just trying to help! This is just the kind of spunk they need to survive, we happily let them test their strength on us.

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Hello once again from the Brothers! I am sure many of you are wondering how Reggie is doing with his harem of decoys. Well exciting news; the other day Reg was spotted presenting a nice big fish to a real live lady tern! Unfortunately having spent so long with the decoys Reg forgot his manners and was a little too insistent our new lady tern take his fish. She flew off, but not to worry, she was back the next day so Reg has an opportunity to try again.

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An example of a chick who had a little too much rock gunnel.

In the area of guillemot chick checks we have chicks from two days old weighing in at 37g to Alfonso a tubby 27 day old chick at 345g. There is quite a size difference between some of our chicks which their parents do not seem to take that into account. In taking measurements on our two day old chicks we found that half of the size of the chick could be accounted for by its crop that was stuffed full of delicious nutritious rock gunnel. The poor chick looked as though he wished he would have stopped eating rock gunnel long before he had. We all feel for you little chick!

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A Leach’s storm petrel, presented here as a popsicle bird.

We at the Brothers are very pleased to announce that we have a Leach’s storm petrel who has decided to take up residence on Western Brothers. The Leach’s Storm Petrel is nocturnal. We have heard them calling several times during the night but until now we have not been able to find if they have actually been nesting here. Our petrel was incubating a single egg deep inside a burrow of loose dirt. Storm petrel’s have a very distinctive odor which you may be able to smell at the entrance of the burrow if it is active. The odor is not entirely unpleasant as they smell very much like old books.

One last update for you. We have finally found some young Savannah sparrows. We had known that they were breeding here but we had not been able to find a successful nest until now. As you can see at this age they are almost perfect spheres with over-sized mouths. Adorable!

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Savannah sparrow sphere with giant mouth.

~SK

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It’s only been a few short weeks, but our first few tern chicks are already taking to the sky. Although adult terns may make flying seem effortless, a chick has a lot to do and learn before its first flight.

First off, you can’t fly without feathers. Tern chicks are hatched covered in fluffy down. While these soft feathers may be warm and provide excellent camouflage, they aren’t very aerodynamic. Over the  weeks, our tern chicks have been going from this:

To this:

To this:

Their wings will grow from less than 20mm long to almost 200mm, mostly by adding long sturdy flight feathers. Their adult wingspan will be close to two and a half feet!

The chicks also grow tail feathers, but they won’t get the long, pointed streamers that mark an adult tern. As a result, you can spot a fledgling by the stubby-looking tail, even if you can’t see the unique color patterns on its back.

All these new feathers need to be kept clean and tidy, so soon-to-be fledglings spend a lot of time preening:

The next step is to build up muscle. Flying is hard work and for the first part of its life, a tern chick doesn’t use its wings for much. To make up for this, tern chicks flapping even before their wings are fully grown.

And of course, before a strenuous workout, it’s always good to do a bit of stretching:

No, not all tern chicks are green. This chick is part of a provisioning study, so he’s been color marked.

Once all their feathers come in, tern chicks start working extra hard to get airborne. It’s actually quite common to see a chick’s weight drop significantly just before it fledges.

It’s not uncommon to see them taking naps, either. Hey, all that flapping is exhausting!

Finally, for some chicks it might take a little extra encouragement. This fledgling wandered onto a neighbor’s territory and finally got airborne as he was being chased away.

While flying is a big step, these chicks still have a lot of growing up to do. Fledglings must master the delicate art of landing, figure out how to fly with a flock, and learn to catch their own food. In the mean time they can be seen begging food from their parents and making cautious practice dives into the water.

Feed me! Feed me! Feed me!

Like the terns, we’ve only got a got a short amount of time left on the island, but I’ve got a post or two more up my sleeve before we say farewell from Ship Island.

-Amy

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The infamous Roseate Tern!

There are currently four colonies with a total of 151 breeding pairs in the state of Maine. On Petit Manan alone, it’s been about a year since the last roseate tern was sighted and even longer since they last successfully nested.

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A Roseate tern nest sharing a space with a Puffin egg.

Roseate terns have either a full black or mostly black bill, a whiter coloration and considerably longer tail feathers then wing feathers in comparison to the arctic and common terns. They tend to nest along the vegetation line close to rocks of the intertidal zone. If not careful, too much activity could cause them to abandon their nests considering their sensitivity to human presence.

This year, we have two confirmed nesting pairs and another possible sighting further along the intertidal. The two nesting pairs each have two healthy chicks which we hope will fledge successfully. Their chicks have black legs and dark mottled down with fine black spots as opposed to the common and arctic tern chicks which usually have orange or pink legs with brighter down and black spots.

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A Roseate Tern chick being banded by our island supervisor Christa.

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An Arctic Tern chick being banded by my coworker Jordan.

Hopefully this means more nesting Roseate terns on Petit Manan island in years to come.

 ~Brittany

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Can you identify which of these birds are Roseate Terns? I’ll give you one hint, there are three in this picture.

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A black guillemot chick grubbed from underneath the boardwalk

One of our most exciting endeavors on this lovely seabird island is monitoring the Alcid burrows around the perimeter of the island. Alcidae is a family of seabirds that includes Atlantic Puffins, Razorbills, and Black Guillemots, all of which breed here on Petit Manan. Unlike the terns that lay their eggs on the exposed ground, each of these species raise their chicks in a protective burrow. Razorbills and puffins always have one egg, while guillemots often have two.

Puffin chick!

Usually burrows are in the crevices between the pink granite rocks that border the island, but sometimes our Alcids choose some unconventional sites, like in the foundation of a fallen building, or under the boardwalk that stretches the length of the island from the boathouse to the lighthouse. In addition to rock burrows, puffins are able to dig burrows in the sod that can be over 6 feet long! Because Petit Manan is a tiny island with an incredible number of breeding birds, we also provide artificial burrows made from wooden boxes or overturned plastic buckets with tubes attached to the entrance so that the birds can crawl into a protected space like they would in their granite or sod burrows.

Alcids establish burrows in early May, around the time we arrive on the island. At the beginning of the season, once the birds have laid eggs, we do a survey of the burrows to determine which ones are active, peering in but trying not to disturb the birds while they are incubating. Later in the season (now!), once most of the chicks have hatched, we do another thorough investigation during which we “grub” the puffin, guillemot, and razorbill chicks and adults.

Applying metal identification bands to an adult puffin’s legs

We remove them from their burrows so that we can put small metal identification bands around their legs, each with unique number/letter combination so that we can resight individuals later and determine how often they return to the island and what other locations they might be visiting year-to-year. We also weigh chicks now and again at the end of the season to monitor their growth. Many of the puffin and guillemot chicks won’t fledge until after we’ve left the island in the middle of August.

Linda Welch (lead biologist) and Jordan (field tech) grubbing a razorbill chick.

“Grubbing” an Alcid can be quite a surprising experience, as it often involves reaching blindly into a dark, slimy crevice and feeling around until you find a fluffy little chick… or until your fingers meet the sharp vice grip of an adult puffin’s powerful bill!

So far this season we’ve noticed that the number of breeding guillemots on the island is on the rise, but there seem to be fewer breeding puffins this year than in years past. We have one confirmed Razorbill chick, and two more possible sites. We’ll keep you posted as we collect and analyze more data about our awesome Alcids!

Linda with a freshly grubbed razorbill chick that is nearly ready to fledge. While puffin chicks take up to 50 days to fledge, razorbills are ready to go in only 16-20 days!

When a razorbill chick is ready to fledge, its dad leads it out of the burrow under cover of night and takes it to the ocean.

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Tern egg on the rocks with decoys behind it

Things are looking up for the seabirds at the Brother’s Islands lately! Events have taken a Tern for the better with the arrival of a new Common Tern pair and their egg. For the past several days now a new pair of terns have taken up residence in the decoy area with our old standby, Reginald McArthur, the tern who has lived here alone for the past several years now.

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Tern Egg laying on the rocks

He seems as happy as we are to have new friends to fish, play, and preen with as the three companions glide around the decoys together calling and circling. All this activity attracted yet another, fourth, tern to the area this morning and it was seen interacting with the others; we hope it will reTern and bring its friends! No one has paid much attention to the egg that was laid on the rocks but we continue to check and see if it has been rolled, an indication that it is being incubated by the parents. So far, it doesn’t look active, but just having the parents around is a huge step in the right direction!

Although you can’t see them, there are 4 Terns, 1 Razorbill, and 3 Least Sandpipers in this view from the blind!

In other news, Razorbill numbers have been increasing in the past few days as we have seen as many as 200+ flying in small flocks across the water. Several, presumably young birds looking for a nesting site, have visited the islands in the past few days, circling and flying very close to it. One razorbill came a mere 3 inches from landing in one of the decoy areas this morning before it veered off to rest in the water close to shore. He was back at it again during lunchtime as we were out doing our “chick checks.”

Speaking of chicks, the little black fuzz balls are continuing to thrive and grow, some have even begun to sprout real feathers and are looking more like gangly teenagers than young chicks now. It’s amazing how fast they grow, gaining sometimes over 1/3 of their body weight every 2 days. We now have 36 chicks in our productivity burrows with more hatching every day. All in all things are looking up for the Brother’s Islands! Here’s to hoping that the next few weeks continue to bring good news. Keep your fingers crossed!

– Julia

A pair of younger chicks, just because they are so cute! Photo by Wingyi.

Our oldest pair of Guillemot chicks: Alfonso and Bernadette, 16 and 17 days old.

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a productivity plot on the west side of the island

tern chick!

One of the important questions that the research team on Petit Manan tries to answer each season is what the growth and survival rates are of the tern chicks on the island. There are over 1,900 tern nests on almost every surface of the island—the rocky shoreline, in amongst the vegetation, and even on the lawn around the lightkeepers’ house that serves as our research station. Each nest usually contains between one and three chicks.

two eggs on the granite berm

Up to three chicks times almost two thousand nests… that’s an impossible number of chicks to keep track of! In order to keep our monitoring effort reasonable, and to reduce the impacts of our presence in the colony, each year we set up roughly 10-12 productivity plots. These are basically tern playpens, each of which contains 5-15 nests. The temporary barrier that we set up at each prod plot allows us to consistently monitor a subpopulation that will be representative of the whole island.

Christa, Brittany, and Dave at a productivity plot

 

Every day we record the number of eggs, pips (eggs that have begun to hatch), and chicks we have in each nest at every productivity plot. We also weigh each chick and put a metal identification band around one of their legs so that they can be resighted and identified for the rest of their lives.

a pipped egg

 

We try to check each plot as quickly and efficiently as possible so that we don’t stress the parent terns for very long, but it can be quite a challenge because tern chicks are really good at hiding!

a newly hatched chick and egg

 

The data that we collect about the chicks’ growth and survival, along with information that we are gathering about the frequency and species of fish feedings (provisioning) will help us paint a more complete picture of the success of Petit Manan’s tern colony. We’ll have more information about provisioning in an upcoming blog, so keep checking in!

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