IBRC #18-B-12

IDAHO BIRD RECORDS COMMITTEE
RARE BIRD REPORT FORM

SPECIES: Lesser Black-backed Gull (Larus fuscus)
HOW MANY: 1 - 1st/2nd Cycle

REPORTER: Doug Ward 8362 Selkirk Ct. Hayden, ID 83835 (208) 762-7107
REPORTER EMAIL: dougward@frontier.com
OTHER OBSERVERS: Gina Sheridan first saw what was probably this bird on December 23rd, 2011 at Wolf Lodge Bay.

DATE REPORT PREPARED: 1 February 2012
DATE SIGHTING OCCURRED: 2, 10, & 15 January 2012

LOCALITY OF OBSERVATION: Blue Creek Bay (Jan. 2nd & 10th) and North Idaho College (Jan.15th), Lake Coeur d’Alene; Coeur d’Alene, Kootenai County, Idaho
HABITAT: Open water lake, mud flats, and ice.
CONDITIONS: First seen about 1pm on 2 January 2012 at about 250m standing on a frozen mudflat under bright overcast skies. Watch for about 30 minutes with my 15-40X spotting scope; mostly at 30-40X. Seen flying on a couple of occasions.

DID YOU TAKE NOTES?: Yes, later the same day
DID YOU CONSULT FIELD GUIDE OR OTHER REFERENCES?: Yes, later the same day
WHAT GUIDE(S) OR REFERENCE(S) DID YOU CONSULT?:
1) “The Sibley Guide to Birds”; Sibley; 2000
2) "Gulls: A Guide to Identification"; P.J. Grant; 1982

DESCRIPTION: Medium sized “white-headed” gull in 1st summer/2nd winter plumage. Plumage: Head and upper chest dirty white with fine streaking of brownish-grey on the nape; streaking around the eye formed a mask. Mantle and scapulars colored dark slate grey; darker than adult California Gulls (L. californicus) standing nearby. Wing coverts and tertials distinctly mottled with dark brown and white. Underparts dirty white. Rump and upper tail coverts whitish. The tail was generally white but appeared to be in mid-molt with some of the retricies broadly tipped with pale brown while others were more narrowly tipped with dark brown. Upper wing: All flight feathers were blackish-brown forming a solid dark trailing edge. Coupled with the whitish rump and white tail, the bird looked saddled in flight. In addition, there was also a dark bar across the secondary coverts. Under wing: The dark flight feathers also showed through to the under wing. Bill / Feet / Eye Color: The bill was entirely jet black except for a narrow cream colored edge to the tip. Eyes were dark. Legs and feet were flesh colored. Structure: Light weight, medium sized gull. An adult Lesser Black-backed Gull (L. fuscus) landed with this bird and was the same size and structure as the immature; “skinny”, long wing projection, well proportioned bill (weak gonydeal angle)
BEHAVIOR: Resting with other gulls on beaches at both locations. Seen flying on a couple of occasions.

HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU? Initially suspected this was an immature Lesser Black-backed Gull (L. fuscus) by this bird's general appearance, dark, slate grey mantle, and size (similar to California Gulls (L. californicus) present. Had previously seen two (2) adult Lesser Black-backeds (see separate report) so wasn't surprised to find another.
HOW DID YOU ELIMINATE SIMILAR SPECIES, AND WHAT WERE THEY? The mostly whitish head, body, rump and white tail with distinct dark tail band, coupled with black bill, blackish flight feathers, and dark “saddled” back eliminates most similar species. Great Black-backed Gull (L. marinus) and Slate-backed Gull (L. schistisagus) can show similar plumages, but as both of these species are large bulky birds they were generally ruled out based on this bird’s light weight structure and long wing projections.
EXPERIENCE WITH THIS SPECIES (AND SIMILAR SPECIES): I've seen a couple of dozen Lesser Black-backed Gulls (L.f. graellsii, intermedius, & fuscus) previously in the U.K., New Jersey, Colorado, and Kenya. There were two (2) adults present on Lake Coeur d'Alene at the same time as this bird.
GENERAL BIRDING EXPERIENCE: I've been birding for 38 years and consider myself advanced.

WERE PHOTO(S), VIDEO, AND/OR AUDIO OBTAINED BY YOU?: None