English and Scientific names:	Slaty-backed Gull Larus schistisagus
Number of individuals:	1 3^rd year
Locality: LOUISIANA:	Cameron
Specific Locality:	Holly Beach
Date(s) when observed:	May 2, 2009
Time(s) of day when observed:	10:25-10:30 am
Reporting observer and address:	Paul Conover Lafayette, LA
Other observers accompanying reporter who also identified the bird(s):	Phiilip Wallace and Curt Sorrells, who found the bird.
Other observers who independently identified the bird(s)
Light conditions (position of bird in relation to shade and to direction and amount of light):	Fine
Optical equipment:	Nikon d50 w/200mm lens; Sony 60x optical zoom videocam
Distance to bird(s):	30-40 yards or so at closest approach.
Duration of observation:	Ca. 5 minutes
Habitat:	beach
Behavior of bird:	Bird was apparently perched a short distance away from a large gull flock when Curt and Phillip spotted it. I overshot the bird and the flock, and noticed Phillip getting out through my rearview. I circled back to see what he was looking at and he told me a GBBG had flown from the area, back to the east. I had zipped right past it in my haste. We zoomed back to the east and found where it had landed with a few Herring Gulls near a big dead fish, and we immediately started getting images. It interacted with the other gulls a bit, as is shown in the photos. As we got closer it flushed and flew into a large flock of gulls near the village of Holly Beach.
Additional Info:	At the time, this bird was an afterthought, as I was in a rush to go see the flamingo pair Curt and Phillip had relocated. My main focus was in helping to document a bird Phillip and Curt had found, so I concentrated on getting images rather than studying the bird, a big mistake. I don’t recall ever looking at the bird through anything but viewfinders. However, I did get decent images. After the bird flew, Curt and Phillip asked if the bird was too pale for a GBBG, and I assumed they were wondering versus a hybrid GBBG. They might have been wondering if it was a different species altogether, perhaps even a Slaty-backed. I thought the mantle seemed dark enough for a GBBG, although it seemed a little faded (which seems normal enough for a May gull on the Gulf Coast). I hope I didn’t derail their identification process. While I was preparing my LBRC reports for the spring season, I started writing this bird up as a GBBG (note file names in address bar). I pulled up my pictures and looked at them for the first time, well over a month after taking them. I noticed the primary pattern, the smudgy eye, the color of the legs, and the mantle color per the photos, and it occurred to me that the bird looked far better for a Slaty-backed Gull. I had assumed that Slaty-backeds were a bit paler, but a look at texts showed that the color was a fair match. I e-mailed a link to my photos to Donna Dittmann at this point to ask her if Slaty-backed Gull could be eliminated.
Description:	A large but not massive dark-backed gull, about Herring Gull-sized. Strong contrast between fresher blackish of mantle and worn blackish of folded wings. Mantle color varied in lighting and posture from dark gray to blackish. Lesser coverts and a few median and greater coverts of the inner upper wing were new and dark. Secondaries appeared darker also, and contrasted with primaries. Primaries, and coverts of primaries were mostly or totally worn and faded. Thus, there was a contrast between black mantle, medium gray inner wing, and faded gray outer wing: generally, fresh/mixed/old. Secondaries dark gray with broad white tips forming broad white trailing edge. White tips frayed from wear. Outer secondaries appeared recently replaced, fresh and darker, as did, perhaps, innermost primaries. Primaries with adult-type pattern but outer primaries faded and worn. Inner primaries (1-3) grayish with broad white tips, dark shaft extending thinly about halfway into white. Middle primaries (4-7) gray with white tongue tips, black subterminal bands, and white tips abraded almost off. On innermost primary with a tongue, white tongue bisected by dark line running broadly along shaft connecting black of subterminal band to gray of rest of feather. White of middle two primaries showing white tongue tips apparently restricted to inner web—but feathers in photo are messed up. Outermost white-tongued primary narrowly but distinctly white on inner web (only?). Outer primaries apparently solidly gray, with no trace of a mirror in my photos. Underwing white with duskiness on primaries and primary coverts, and apparently on underside of newer secondaries. Sparse scattered dark marks on median coverts. Tail with more than one generation of feathers? Inner pair of rects was white and worn to the shaft at tip. Outer pair seemed largely white with a dark blob near distal tip, while other rects were white for about proximal ½ , becoming mottled or streaked black-and-white (appearing grayish) for about next ¼, then solidly dark- or black-tipped for distal ¼ or so. Rump white. Underparts and head white with scattered sparse dark markings of winter plumage. Hindneck slightly dusky with streaking. Dark smudge around eye. Prominent supraorbital ridge. Irides pale yellowish-white. Bill large but not massive, deeper at tip, pale at base, dark at tip, with zig-zag line of demarcation as dark angles up and back towards culmen on maxilla and up and back toward cutting edge on mandible. Dark appeared to extend narrowly back along cutting edge of mandible as well. The exact color of the pale base of the bill is hard for me to discern. Hopefully it’s more apparent in Phillip’s video. Legs and feet obviously pinkish, with no hint of other colors. Pink quite vivid, not pale.
Voice:	Not heard.
Similar species:	I think the main possibilities in this area are: Female Great Black-backed a possibility. Size of bird and bill size should be OK for a female GBBG. Is this primary pattern found at this age in that species? Leg color would be odd for GBBG. Hybrids and backcross hybrids of GBBG and Herring Gull a possibility. There is the very real possibility that this bird is some kind of a GBBG x Herring. If this is the case, and if that mix can look like this, then many East Coast records of Slaty-backed Gull probably suspect.
Photographs or tape recordings obtained?	I shot photo and video, Phillip shot video.
Previous experience with this species:	None
Identification aids:	Standard gull references: Olsen and Larsson, Dunn and Howell. Helpful commentary from Dan Gibson, Alvaro Jaramillo, Bruce Mactavish, Joe Morlan.
This description is written from:	Memory, photo reference.
Are you positive of your identification? If not, explain:	My confidence in the identification has zero bearing on its final determination. I feel that this bird matches Slaty-backed Gull, but might other possibilities match? June 21: I can’t help but feel that this bird is a Slaty-backed, and experts on this species back this viewpoint up. However, it feels odd to me that a species that should seemingly be more difficult to prove with just photos falls into place so easily. Certainly gull records with much better support have proven harder to pin down. My level of confidence is influenced by caution, basically like leaving my finger on a chess piece while I ponder a move, but basically I feel very good about this record.
Reporter:	Paul Conover
Date and time:	June 11, 2009 10:00 AM June 21, 2009: Additional comments added, and questions about details that have been answered to my satisfaction in the interim deleted.