Western Gull (occidentalis/wymani)

Western Gull
(occidentalis/wymani)

IMAGES:
occidentalis
1) juv and first winter birds standing and in flight
2) unusual pale first summer bird the Ventura Mystery Gull
3) second winter
4) third winter
5) adult birds

wymani
1) 2 juv/first winter birds standing and in flight
2) second winter standing and in flight
3) third winter
4) pale-eyed third winter and adults

DESCRIPTION:

WESTERN GULL (24"-27"; 52"-56") occidentalis, wymani

BILL SHAPE: thick and blob-ended; 4 1/2 times eye diameter in length; gonydeal angle large; culmen w/ steep curve to tip
HEAD SHAPE: rather small and rounded; may have a small pinheaded look
WING EXTENSTION: bill length or less
POSTURE/HABITS: ...
	FIRST WINTER	SECOND WINTER	THIRD WINTER	ADULT WINTER
BILL COLOR:	black; some pink at base by summer	variable; usually with pale pink or yellow base and culmen; black subterm band or tip and dark around nostril	variable; usually w/ pale yellow base, culmen, and lower edge; dark subterm band; gon spot possible	bright schoolbus yellow, nearly orange-yellow w/ pale yellow tip; gon spot orange-red
LEG COLOR:	dirty dark pink	dull dirty pink	pink to light pink	light salmon pink
IRIS/ORB RING:	dark	dark; achieving adult color by late winter or spring	as adult	gold to brown, appearing dark from a distance, on occidentalis, light yellow rare; pale gray on wymani; orb ring mustard yellow
HEAD:	dark sooty gray; often solid around eye and auriculars, giving masked look; diffusely streaked or blotchy elsewhere; paler behind auriculars, on nape and throat	smudged dusky, esp around eye and on rear crown, aurs, and lower nape; streaky only on nape and neck sides; aur edge is palest	smudging across crown, auriculars, and lower nape; darkest across nape; no streaking; may be nearly white	white all year; very slight winter smudging possible in occidentalis
UNDERPARTS:	blotchy to uniform dark sooty gray from breast to belly; undt covs irreg. barred	white w/ light mottling on breast and belly; undt covs white	some mottling possible on breast sides; belly white	white
PRIMARIES (folded):	blackish	black w/ faint pale tips possible	black; tiny A-spots rarely visible	black w/ A-spots larger than eye, except A10, same size as eye
PRIMARIES (in flight):	blackish above and below	outer Ps black; inner Ps paler w/ white trailing edge	like adult but usually lacks mirror and A-spots; black area more extensive, esp on P covs	extensive black on outer Ps; large mirror on P10; rarely small mirror on P9; often slight pale tongue on P5; often black mark on P4; quite dark underneath
SECONDARIES (in flight):	blackish above and below w/ pale fringe	dark w/ large white trailing edge	as adult	trailing edge about 1/2 bill length; quite dark underneath; shows white skirt when standing
TERTIALS:	very dark w/ white tip or subterm cresent or chevron	solid dark g-b w/ extensive marbled tips	adult gray w/ traces of brown, esp on inner webs	adult gray w/ white cres., about 1/2 bill length
GREATER COVERTS:	fairly solid dark brown w/ pale fringe and sub- term spot; inner feathers more spotted; appears as a dark bar in flight; prone to fade brownish	solid med dark g-b, often w/ extensive pale or marbled tips	adult gray w/ traces of brown; slightly mottled	adult gray
LESSER & MED COVERTS:	dark brown w/ pale edges giving a dark scaled or mottled look	med g-b w/ darker centers, giving a muddy look; some adult gray possible	adult gray w/ traces of brown	adult gray
SCAPULARS:	fairly solid sooty g-b w/ dirty pale fringes, looking scaled on young birds but darker later	adult gray; white scap. cresent 1/3 bill length often visible	as adult	adult gray w/ white cresent about 1/3 bill length
BACK:	as scaps, but w/ less pale fringe, appearing darker; may have some adult gray	adult gray mixed w/ bits of brown	as adult	adult gray is med dark in occidentalis (not much darker than California); quite dark in wymani
RUMP:	quite white, filled w/ irregular dark bars	mostly white w/ some dark smudges	white	white
TAIL:	solid black w/ pale fringe; faintly mottled bases of outer retrices from below; rarely pale bars on outermost webs	all dark w/ obvious pale fringe; pale mottled bases to outer retrices	white w/ irregular jagged subterm black band; outer webs white	white

The was table created by Steve Hampton and is intended to futher our knowledge of gull identification. Please email me at shampton@ospr.dfg.ca.gov if you have any suggestions for updating or improving this table. Thanks.