Lesser Black-backed Gull (graellsii/intermedius)

Lesser Black-backed Gull
(graellsii/intermedius)

DESCRIPTION:

LESSER BLACK-BACKED GULL(20-24"; 49-50") graellsii/intermedius

BILL SHAPE: slightly smaller and thinner than Herring; 4x eye diam.; gon angle small to medium; culmen slopes gently to tip
HEAD SHAPE: rather rounded with slightly flat crown
WING EXTENSTION: long; 1-1.5x bill length
POSTURE/HABITS: usually appears smaller and more graceful than Herring
	FIRST CYCLE	SECOND CYCLE	THIRD CYCLE	ADULT
BILL COLOR:	black; no pale base until summer	variable; usually pale w/ black subterm area	yellow w/ dark subterm band or mark	dark yellow w/ red or orange-red gon spot; pale tip
LEG COLOR:	dull pink	usually pink to pale pink	yellowish to grayish-flesh	pale to dark yellow
IRIS/ORB RING:	dark	dark or pale	as adult	pale yellow; orb ring red
HEAD:	rather pale, w/ dark mottling or streaking around eye, auriculars, and rear crown; young birds have solid blackish patch from front of eye to auriculars	white w/ thin streaks over crown and aurs; darker streaks on nape and neck sides	as adult	extensively streaked w/ fine lines over crown and face; thicker streaks on nape and neck sides to upper breast
UNDERPARTS:	blackish mottling from lower nape and neck sides to breast sides and flanks; belly paler; undt covs spotted	white w/ extensive dark streaking or mottling on breast sides and flanks	white	white
PRIMARIES (folded):	blackish	blackish	black; A-spots tiny or lacking	A-spots evenly spaced except 9-10 closer; all are smaller than eye
PRIMARIES (in flight):	blackish above and below	blackish above and below	as adult but A-spots and mirrors often lacking; black area slightly larger	med to large mirror near tip on P10 (rarely terminal); small mirror on P9 often on gr.; black band on P5; often dark mark on P4; gray area quite dark from below
SECONDARIES (in flight):	blackish above and below w/ very narrow pale fringe	dark above and below w/ pale fringe	as adult	adult gray w/ broad white trailing edge about 1/2 bill length; strong contrast with gray area below
TERTIALS:	very dark brown w/ crisp white edge; may have diffuse pale area near tip or small notches on sides	dark gray w/ large pale marbled tips	as adult but mixed w/ brown	adult gray w/ large white crescent about 2/3 bill length
GREATER COVERTS:	solid dark brown-black w/ obvious pale fringe and subterminal spot; more barred and spotted on inner feathers; appears as a dark bar in flight	mottled adult gray and brown	adult gray mixed w/ brown	adult gray
LESSER & MED COVERTS:	rather dark brown w/ pale edges, creating a scaled look (very bold in young birds); muddy later in winter	adult gray w/ dark subterm anchors	adult gray mixed w/ brown	adult gray
SCAPULARS:	similar to med,les covs	adult gray w/ dark centers	as adult	adult gray w/ little or no white crescent
BACK:	similar to med,les covs	adult gray w/ dark centers	adult gray	adult gray is med dark on graellsii, very dark on intermedius
RUMP:	appears quite pale; white with some dark mottling	white	white	white
TAIL:	large black band w/ pale fringe; all but inner retri- ces w/ extensive irreg pale barring at bases; outer- most webs white w/ dark bands near tip	large black subterm band w/ extensive marbled base; outermost webs white	white w/ variable subterm marks, esp on inner retrices	white