Archive for May, 2010

The 2010 season is off to a great start with beautiful weather for our first two trips on May 18th and May 24th.  (Who has visited The Graves on a day like this !?!)  On both days we took advantage of calm seas and conducted boat-based counts of double-crested cormorants and gulls in the Outer Islands.  Overall numbers of DCCO, GBBG, and HERG appear very similar to previous years (see summary attached), however we did see some significant shifts in spatial distribution.  There appear to be slight declines in several colonies and a significant increase on Middle Brewster, where the cormorant colony has spread under sumac adjacent to the nesting cliffs.

Middle Brewster 2009 (no DCCOs)

Middle Brewster 2010 (new DCCO nests under sumac).

We also noted a marked increase in the presence of Great Cormorants in the Outer Islands, with 6 adults and 5 immatures detected on 5/18, and 4 adults and 3 immatures detected on 5/24.   Great Cormorants (http://www.allaboutbirds.org/guide/Great_Cormorant/id) are a more northern species that winter in Boston Harbor, but nest further north with a few sites in Maine and Canada.   In colony sites in Maine, Bald Eagles are thought to be a significant source of cormorant predation, though the worldwide populations of this species are secure.

Some Recent Press on Great Cormorants (thanks Bob!):



During boat-based surveys, we also detected a total of 3 pair of American Oystercatchers during each survey in their predictable locations on Calf, Middle Brewster, and (possibly) Outer Brewster.  Male Common Eiders were still present in the area and several groups of females with chicks were observed.  We had a total count of 20 chicks on 5/18 and an astounding 226 chicks on 5/24!   Our all time top count of eider chicks on the water was 279 chicks on May 30, 2008, so it appears the eider are off to a great start this year and possibly a bit ahead of schedule.  We will continue to monitor common eider crèches during the month of June.

During a landing on Lovells Island on 5/18, 5 feeding American Oystercatchers were detected, but no evidence of nesting was observed.  No terns, spotted sandpipers, eider, or rabbits (!) were seen.  A landing on Georges Island on 5/24 resulted in a similar dearth of waterbirds, but was a great opportunity to learn more about the island from ranger and waterbird volunteer, Andy Leahy.

Other items of note during our first week were peregrine falcon sightings on both days and a Red-necked Phalarope on 5/24.

Looking forward to a busy season & hoping for more great weather! -Carol


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