ML86741951

Age

Not specified

Sex

Not specified

Observation details

***Mega. I arrived to Jodrey Fish Pier at 09:45 as my first stop of the day on Cape Ann. There was a large flock of sleeping gulls on the sparsely vegetated roof of the building with the yellowish bronzy siding. After an initial scan, I picked up on a medium-toned mantle hidden amongst a sea of Herrings and Great Black-backed Gull mantles. After about 20 minutes the gulls had shifted around, revealing most of this third cycle gull. I started detecting traits that suited Slaty-backed Gull, and ruled out other medium gray-mantled gulls. The shade of gray was much paler than nearby Great Black-backed Gulls, much darker than nearby Herrings, and noticeably paler than a nearby Lesser Black-backed Gull. The secondaries of the folded wing were gray, edged with brown. In flight, the lesser coverts were mottled brown. The top of the mantle was a solid gray, suggesting a two-toned back. The feathers immediately surrounding the eye were dusky, creating an shadowy appearance around the eye. The rest of the head was pale overall, but patterned regularly with brown smudges and streaks. The rest of the body was white with a few brown specks. The legs were a deep rosy-red pink, with no yellowish or paler pink tones. The tail had a faint subterminal band composed of small gray spots towards the tips of the rectrices. P5-P10 were tipped white; P10 had a large white mirror; P7-9 were dark with suggestions of white tongues on the inner vanes. P5-6 were gray with black subterminal bands, and large white tongues. The white tongues, mirrors, and tips created the “string of pearls” that is commonly cited as a critical field mark on Slaty-backed Gull. This bird was approximately the same size as nearby Herrings. The chest of this bird was bulky, and the legs were short relative to the Herrings. I spent most of the day studying this gull, noting its behavior and movements. The bird spent nearly the entire day preening and sleeping on the roof with the other gulls. At 13:00, we baited it in with bread. The bird was cooperative beyond all expectations. The Slaty-backed flew, chased other gulls, and called within 50 feet of a large number of delighted observers. The calls were mostly a long, high-pitched, shrill whine. It gave a nice long call that was similar to other gulls, although again was higher-pitched and shriller. Recordings of that long call are below. At approximately 14:00, the gull landed on the docked “Beauport” cruise ship and then returned to the roof. It remained sleeping and preening on the roof until just before 17:00, when most of the gulls moved over to the docks immediately southeast of and easily visible from the Jodrey Fish Pier. The channel dividing the pier and these docks is labeled as “south channel” on Google Maps. At 17:30, we left the Slaty-backed Gull settled into its roost for the night on the second dock from the south amongst 600 Herring Gulls, 250 Great Black-backed Gulls, 5 Iceland Gulls, 2 Glaucous Gulls, 2 Lesser Black-backed Gulls, and a Great Black-backed X Glaucous Gull hybrid. There was no sign of the Thayer's then. At that point, I was ready to go to roost as well. This individual was documented in three locations between 2/16-24/2018 at the following locations and dates: 2/16: Fresh Pond, Cambridge, MA (Jeremiah Trimble; https://ebird.org/checklist/S42995255) 2/19: Jodrey Fish Pier, Gloucester, MA (this checklist) 2/23-24: Hatch Hill Landfill, Augusta, ME (Doug Hitchcox; https://ebird.org/me/checklist/S43120750)

Technical information

Model

Canon EOS 7D

Lens

EF400mm f/5.6L USM

ISO

320

Focal length

400 mm

Flash

Flash did not fire, auto

f-stop

f/5.6

Shutter speed

1/1600 sec

Dimensions

3283 pixels x 2189 pixels

Original file size

5.16 MB