Monday, November 1, 2010

Seabird Observations

It's been an exciting and blustery week studying seabirds from the Endeavor’s flying bridge. The sea state has rarely been below Beaufort 4, and spotting some of the smallest seabirds, e.g., dovekies, has been a challenge. I use 10 x 42 binoculars to help with identification, and observations are recorded using GPS software specifically designed for top predator surveys. Age, sex, and behavior of seabirds are logged when possible, as well and association type, e.g., whale, tuna, other seabirds. The spatial aspect of the data helps us link the prey field, as determined by acoustics and net, with the distribution of predators (seabirds & marine mammals).

Greater shearwaters breed in the south Atlantic on Tristan da Cuhna, Nightingale Island, Inaccessible Island & Gough Island. Greater shearwaters found on Georges Bank this time of year are likely nonbreeders (photo: T. White)
I enjoy surveying Georges Bank this time of year because arctic breeding seabirds begin to make an appearance. Species such as: northern fulmar (Fulmarus glacialis) black-legged kittiwake (Rissa tridactyla), great skua (Stercorarius skua), northern gannet (Morus bassanus), and the alcids: razorbill (Alca torda), Atlantic puffin (Fratercula arctica), common murre (Uria aalge), thick-billed murre (Uria lomvia), and dovekie (Alle alle). Some alcid species can reach depths greater than 100 meters in search of prey. Dovekies are interesting alcids to find on Georges Bank because they breed very far away, in places like Greenland and Spitsbergen. The winter population of dovekies on Georges Bank has recently been increasing, and arriving earlier in the season. It is possible that dovekies are shifting their winter distribution farther south in search for food such as krill.

Black-legged kittiwakes breed in northern Canada & winter on Georges Bank (left 1st winter; right adult). photo: T White
Migrating non-seabird species have been spotted over Georges Bank the last few days. Groups of common eiders (Santeria mollissima), white-winged scoters (Melanitta fusca), and single common loons (Gavia immer) were observed streaming by the ship. A single snow bunting (Plectrophenax nivalis), 6 dark-eyed juncos (Junco hyemalis), 1 female red-winged blackbird (Agelaius phoeniceus), a mourning dove (Zenaida macroura), and a female purple finch (Carpodacus purpureus) have all stopped to rest on the Endeavor.

Tim on the flying bridge logging observations. photo: Peter Wiebe

No comments:

Post a Comment