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Posts Tagged ‘Tern Productivity’

Hello everyone, this is Bobby writing to you from Ship Island with some breaking news.

The bird word must have gone around, because as of Thursday, July 11th, 321 nests have been found and marked with more being discovered every day! The chaos on the tern nesting beach area is beginning; the eggs laid in late June have begun to hatch this week. Soon our island will be filled with extremely adorable fuzzy chicks who love to run and hide in whatever grass or shelter they can find!

fuzzy boy

One of the first chicks on Ship, easily one of the softest objects one could ever hold.

These toddler-like chicks are extremely curious and will wander away pretty far from their nests if given a chance. With them running around all over, it can be difficult to tell how the colony chicks are doing health wise and how many of these chicks are surviving to adulthood. This is answered through a protocol that all of the islands perform known as productivity plots. This may sound like a fancy term, but essentially Colin and I determined a group of nests with eggs that were laid earlier in the season (in our case in late June) that neighbored each other and constructed fencing around them to enclose this area.

 

COTE on colins head

Colin (pictured) and I constantly had terns going at our heads to protect their nests while we constructed productivity plots. This one very nicely went feet first to our heads instead of the usual sharp bill first.

This keeps the chicks from our nests of focus from running all over the beach getting into trouble, that way we can determine how many chicks are surviving to adulthood and the size increases of each chick from each nest within our plots. To determine which chick is which, we put stylish metal BBL bands on their right legs that give them a unique identification number for life in a large online database. Colin and I then check each nest in each plot every morning to monitor the eggs and chicks. I am not a parent, but I imagine how I feel when we look for the chicks every morning it is similar to the stressful situation of a parent trying to find their misplaced kids, as Colin and I are really attached to our chicks in the plots. It has been amazing to see the transformation from egg to chick, and soon from chick to fledgling. Watching them grow up has been so special for Colin and I, and we can’t wait to see each chick’s journey continue. More updates coming soon!

wet baby tern

One of the many chicks hatching this weekend, this one hatched within the hour before this photo with a big world to explore!

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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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