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Posts Tagged ‘Common Tern’

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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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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We are packing our gear and cleaning the cabin!  Jennie and I head back to the mainland today and we wanted to give you one last update on our season.

We crossed off each day after we finished the dinner dishes. Its wild to think that its all over for 2011...

Census

The Gulf of Maine Seabird Working Group (GOMSWG) census was started on June 17, 2011, and finished on June 20, 2011.  The Tern nest count for the census was 484, with a Lincoln Index of 1.029, resulting in a corrected total of 498 Tern nests on the North End of Metinic.  This represents about two thirds of last year’s population.  Common Tern nests were marked with a blue flag, while Arctic Tern nests were marked with a red flag.  On the NE Point we identified 307 of 498 nests (61% of NE Point colony).  We counted 122 ARTE, 185 COTE nests.  We estimated that the colony was comprised of 40% Common Terns, 60% Arctic Terns. The South End of the island is privately owned and was surveyed by boat, 2 pairs of Terns were present, but no nests were confirmed.

Productivity

Fledging/reproductive success was low this year for Arctic Terns (under the 1 chick/nest USFWS goal), but Common Tern productivity improved from last year and met this goal.  The Arctic Terns suffered from widespread predation events early in the season which resulted in the loss of many eggs and young chicks.

Provisioning

We were able to follow 6 Common tern and 8 Arctic Tern nests throughout the season, for a total of 96 observational hours and 599 feedings. COTEs fed at an average rate of 1.6 feedings/hour, while ARTEs fed at 0.7 feedings/hour.  Both Arctic and Common Terns delivered Atlantic Herring most frequently to their chicks consisting of about 55%and 30% of their diet respectively.  Butterfish was the next most frequent delivery for both species, making up about 30% of deliveries.  Herring deliveries gradually declined and butterfish deliveries gradually increased as the season progressed.  Feedings overall slowed considerably starting in the third week of July especially for Arctic Terns.

Guillemots

32 Guillemot nests were located with a hatch success of 62% and an egg depredation rate of 12.9%.  This data is not a complete set because of the number of guillemots incubating through all checks.  Three adults were still incubating at the end of July, so hatch success could be higher than calculated. 19 chicks were found and 14 were banded, weighed, and measured.

Petrels

53  Leach’s Storm-petrel burrows showed signs of activity (smell, fresh piled dirt, activity at night) early in the season, however only 7 were noted to have eggs or adults present at the end of July.  At the end of our field season, 17 burrows were no longer active and 29 still showed some activity yet nothing could be seen with the burrow scope.

Common Eider

Eider numbers were very low this year averaging only 50-100 eiders at each morning count. Previous years Eiders had averaged between 150 and 300 for morning counts.  Only 30 observations of eider crèches were documented (at least 4 separate crèches).  Five eiders were banded by USGS and MDIFW.

Incidental Sightings

Species highlights: Northern Gannett, American Oystercatcher, Razorbill, Atlantic Puffin, Whimbrel.

We had a tremendous amount of fun out here this summer, and we hope you all enjoyed being able to follow along!  If we peaked your intrest and you would like to get involved or support our efforts makes sure to check out the Friends of Maine Seabird Islands site: http://maineseabirds.org/html/home.html!

Signing off!

-The Metinic Crew

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…And breakfast, and lunch! For four days every week we each perform a “provisioning” stint of three hours.  During provisioning stints, we observe our selected 5-7 nests of chicks to see what their parents are bringing them to eat and how often each chick is getting fed. We record the prey type, the size of the prey in comparison the to adult’s bill length, which chick from which nest is getting fed, and the time of the feeding. Charlie has been watching 6 Arctic Tern nests, with a total of 6 chicks, and Jennie has been watching 6 Common Tern nests with a total of 12 chicks!  You cant leave the blind during a provisioning stint, so if you need to pee it means taking a trip to ye ol’ coffee can…

Common Tern Provisioning nests (Orange Flags)

In order to tell all our chicks apart we color them with markers! Each nest is a different color, and then if there is more than one chick in the nest, the first born chick (the A chick) gets colored on the head, and the second born chick (the B chick) gets colored on the breast.  It is quite entertaining to watch little brightly colored chicks run around!

Two Common Tern provisioning chicks. The purple head denotes an "A" chick, and the purple breast is the "B" chick.

One of the big challenges of provisioning is to correctly identify the fish species. This can be difficult since some of the feedings happen extremely fast! Those chicks are hungry!  Some of our common fish are Atlantic Herring, Butterfish, Pollock, Sand Lance, Hake, Needlefish and a variety of invertebrates.  From our observations, we can analyze the chicks’ diet composition and feeding rate.

A Common Tern with a Pollock

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Tern on an egg (through the spotting scope)!

Life and death unfolds at an alarming rate here on Petit Manan Island. Thousands of eggs hatch every summer. At the peak of the season, Common Terns, Arctic Terns, Atlantic Puffins, and Black Guillemots (just to name a few) can be found on almost every surface and in every crevice on the island. But a whole host of predators are fully aware of this phenomenon – in June, PMI is ripe with adult birds, chicks, and eggs all ready for the picking. Peregrine Falcons, Bald Eagles, Harriers, Greater Black-backed Gulls, Herring Gulls, and Laughing Gulls are just a few of the predators that have already found a few meals on PMI this summer.

The Crew (minus Christa) painting popsickle sticks

The PMI Crew (minus Christa) painting popsicle sticks

In all this madness and mayhem, the research team is trying to get a gauge on the effects of predation on some of the species nesting on the island – especially Arctic and Common Terns. How many eggs are being laid and how many are being predated for each species? With several hundred nests already established, it’s a little difficult to keep track of such details! So over the years, the Refuge staff has devised a method of labeling nests with small wooden stakes – more commonly known as Popsicle sticks!

Stake indicating the nest number, species (COTE = Common Tern), date inserted and number of eggs, and the number of eggs at the check date

While observing the tern colony from the blinds scattered around the island, whenever we notice a nest we place a Popsicle stick (which we paint purple so that we can easily spot it on the ground) nearby that indicates the stake number, the date that the nest was discovered, the tern species, and the number of eggs in the nest. As that number changes (because more eggs are laid or because of a predation event), we update the stakes accordingly. At the end of the season we use this data to calculate success rates for each species.

Arctic tern on its nest, marked by a purple stake

The stakes will also come in handy when we do the big island-wide census, which is coming up soon! Check back for updates!

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Sunset during the evening perimeter walk

During our evening perimeter walk today, we spotted the first Common Tern egg of the season!

Common Tern egg

This little speckled beauty is about the size of a walnut and is amazingly well camouflaged. The creamy base color of the egg matches the minimalistic dry-grass nest perfectly, while the soft-toned speckles help it blend into the shadowy substrate.  Tern eggs are predated by Herring Gulls, Black-backed Gulls, and Laughing Gulls, all of which frequent PMI, so this cryptic camouflage is critical to the survival of the little tern-to-be. Keep checking back for updates, because you know what comes after eggs……… chicks!

Common Tern preening

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