Verification of Unusual
Rec. # 3-2001
|Scientific name:||Larus glaucescens|
|Date:||12 Nov 2000|
|Time:||3:30 - 4:00 pm|
|Length of time observed:||30 minutes|
|Location:||Farmington Bay WMA|
|Distance to bird:||30 meters|
|Weather:||cloudy, light snow falling|
|Light Conditions:||overcast, dim|
|Detailed description of bird:||This was a large, bulky gull with a large flat forehead. A very large all black bill with a distinctive sharp gonydeal angle. Uniform all brown body plumage including primaries and tail which were the same brown color as the rest of the body plumage. The Gull had a uniform pattern of pale markings or fringes running across the lesser and median wing coverts. Pale spots were throughout the scapulars. Pale fringes visible on tips of primaries. Pink legs, dark eye.|
|Song or call & method of delivery:||None.|
|Behavior:||Sitting still at the edge of water impoundment|
|Habitat:||Farmington Bay, open water, wetlands|
how were they eliminated:
Glaucous Gull: 1st winter. 2 toned bill - pale base with
black tip. Overall body plumage paler (almost white) with coarser & more
irregular pattern of markings on scapulars. paler primaries contrast with rest
of the body plumage.
Thayers gull: 1st winter: Smaller bill, smaller more rounded head. Primaries darker than mantle. dark band on tail, darker than rest of the upper body plumage.
Herring gull: 1st winter: Dark brown primaries and secondaries contrast with rest of body plumage, Dark tail, Dark barred rump.
Glaucous-winged - Western hybird: This is a possibility. Even though this is a darker brown gull than other glaucuos-winged I have seen (There is variability in color among juvenile/1st winter birds) it is still uniform color, shape, and specific characterisitcs of a Glaucous-winged gull. A hybrid would probably show somewhat darker wingtips than the rest of the body plumage, with a less flat forehead and generally have more integration of characteristics of the 2 hybridized species. This is assuming of course that both parents were pure birds of their respective species.
Through my literature search it became apparent that hybridization of Glaucous-winged gulls with Western, Herring, and even Glaucous gulls is common. In fact, some populations in Washington are mostly hybrids and backcrosses with very few pure birds (glaucous-winged/Western).
While the gull described and photographed fits very closely the description of glaucous-winged gull it may in fact not be a pure bird because of hybridization and or backcrossing from the distant past.
|Previous experience with this & similar species:||I have seen several apparent Glaucous-winged gulls on the pacific coast and a few in Utah the past several years.|
P.J. Grant: Gulls a guide to Identification. Second edition.
The Sibley Guide to Birds.
|Description from:||Notes at time of sighting.|
|Observer's address:||887 Germania Ave. Murray, UT 84123|
|Observer's e-mail address:||firstname.lastname@example.org|
observers who independently identified
|Date prepared:||27 Dec 2000|
|Additional material:||Photo, Original Document|
Go to Main List of Sighting Under Review