ML512237501

Age

Not specified

Sex

Not specified

Media notes

Slaty-backed Gull (adult): Provincetown Harbor, Provincetown, MA - 11 December 2022

Observation details

^ Adult roosting on breakwater among numerous GBBG and HERG. Initially spotted by (and subsequently identified by) Amy O'Neill. Although rather distant from our viewing position on the SE corner of the pier (approximately 300 meters away, as measured on Google Earth), notable features included about Herring Gull sized but with a stocker, shorter-winged appearance; mantle was very dark gray, noticeably paler than the adjacent GBBGs, but much darker that a HERG and darker than most LBBG. There was a broad, prominent white tertial "skirt," broader and more conspicuous than on the other gulls. Although white mirrors in the primaries were visible, the bird was too far away and never seen in flight, so the extent or shape of the mirrors could not be determined. The head was white with dark feathering around the eye; given the distance (and my ageing eyes!) I could not see any dark streaking elsewhere on the head or the nape, though in the photos the head appears duskiness on top of the head. The bill was yellow and appeared rather narrow with no discernable swelling at the tip; there was some darker coloration distally, but I was unable to discern whether it was red, black, or some combination of the two (and hard to determine from the photos). The legs and feet were bright pink, much brighter than the adjacent gulls. Total viewing time was about 15 minutes, after which the bird disappeared while we were looking away (many of the gulls had previously flown off heading east). The bird twice changed positions on the breakwater, but neither of us saw it move on either of those occasions. I was able to take very distant, but I believe diagnostic, photos with a Sony 200-600mm lens and a Sony A9ii camera.

Technical information

Model

ILCE-9M2

Lens

FE 200-600mm F5.6-6.3 G OSS

ISO

1250

Focal length

600 mm

Flash

Flash did not fire

f-stop

f/6.3

Shutter speed

1/800 sec

Dimensions

900 pixels x 600 pixels

Original file size

519.67 KB