More Gull Class Notes

Here are some additional notes from the 2010-2011 Fall/Winter class on Gulls:

First here is a link to four tables.  One will help you group gulls by bill shape and behavior, i.e. Tern-like gulls, and Typical Gulls.  The next groups North American gulls by their first cycle molt strategy. The next  compares the mantle and wing gray-scale on the Kodak scale, for comparison.   Finally a memorization table Ryan put together to facilitate learning the plumage details of the possible WA gulls.  Students will do themeselves well by downloading and printing these for study.

The rest are some notes from the class.

Herrmann’s gulls will chase other gulls like a Jaeger, and young birds can even have a white flash in wing.

Parasitic Jaegers come thru the Puget Sound in the fall.  Point-no-point is a good place in the fall.

Gonydeal angle is the jutting part of the bottom of the bill.

The orbital ring is around the eye, is dried skin, and is affected by hormones.  Brighter in breeding plumage.

Glaucous-winged x Western gull:  aka Olympic or Puget Sound gull.  This is what makes gull watching in WA interesting.  Maybe up to 75% hybrids in some colonies.  Most birds from along the coast and in Strait of Juan de Fuca tend to Western.     In birds that tend to Western Look for smudgy head in basic plumage,  for too light a back for mixed orbital ring color, for dark but not black wing tips.    If it tends to GW, look for too bright a bill, or too dark a wing tip, or too dark a back.     IN juvenile tend to be murky colored overall, not a crisply contrasty as in Western.

Molt of a Western Gull:  timing:  born May or June in Juvenile plumage, strongly variegated, with noticible barring on upper tail coverts, black bill, blackish tail.  Starts PA1 molt in August and cont thru October, changing out the head and some of the scapula.  Suspends in midwinter and starts againin Feb, finishes in May.  So thru first winter brown, dark bill, highly variegated, and does not change much until March.  PB 2 molt starts in April thru September.  So thru the first year only not in molt about 3-4 months.   PB 2 plumage has pink base on black bill, but otherwise looks like a juvenile, brownish.   PA2  from mid Aug, to Oct, suspended thru winter, then Feb – May.  molt into pale base on the bill, so by second spring will have dark backs, clear heads, but coverts look juvenile.  PB3 molt from April – Oct.  Basic 3 is adult-like.  Very small differences, maybe black on tail, maybe black primary tips, maybe black on distal bill, PA3 is from August 20- duration hard to ascertain.  PB4 molt from Mid may to June thru Nov.  Adult-like after  PB 4.

Black-tailed Gull:   a primitive white=headed gull.  Asiatic,  3 WA records.  All adults.  4 cycle gull.  Kodak 8-9.5.  Long primary projection.  Lack mirrors in the wingtip.   (ie no white area with black both proximal and distal)    Black band on tail sub-terminally in adult.  Long bill, eye arcs,   Very slight gonydeal angle.   California gull similar color, not quite as dark.  Dusky hood, almost comes around the neck.

Ivory Gull:  Medium sized.  No PA molt.   White all year round, mew gull sized, young bird black faced.  One WA record.  Simple basic, one molt a year.

Gulls bills, lower bill has two plates, fused together at the gonydeal angle.  This allows them to widen and swallow big things.

Little gull:  complex alternate.  Like a little Boneparte’s Gull.  100 WA records thru 2000.  Almost all from the Puget sound area.  Almost always on fresh water, with Bonepartes.  Large lakes.  Sept and Oct are the best months.  A few spring records, mid March thru mid june.  Few winter records.  Average 2/ year.   B y sept have gone into first winter plumage.  11” smallest gull in the world.  Adult has blackish underwings. Dark bill, dark auricular patch.    Juveniles may not have dark underwings.   In Juveniles much darker upperwing markings.    Kodak 4.5-5.5

Boneparte’s is a masked gull, not a hooded gull, cap only comes to the mid-nape.   Stay thru mid-winter.   Go farther south.   First winter has carpal marks, black terminal tail.  Big field mark is the white leading upper wing edge triangle.  Kodak  5-6.  Rare to uncommon in E WA.   Cyclic, some years more, some less.

Black-headed gull:  >15 records, most in fall.   Kodak   4-5.   Lighter backed than Boneparte’s, pinkish legs, bill is pinkish to red, slightly larger than Boneparte’s, twin lines on top of head, dark under-wing primaries.

Franklin’s Gull:  a hooded (not masked) gull, hood in breeding plumage comes way down on the neck.   Seen 5-20 times annually in W WA, most in the fall, June-Nov.   Often up ot a 350 kilometer from the breeding sight.  Only a few spring records in W WA.  Since 2000 44 E WA reports, most May- Early- June.   Maybe expanding breeding range.  Breed at Mal Huer.   Possible to see a Sept bird with some juvenile plumage, but most of our birds are first winter.  Smaller bill, more complete hood, and outer two retrices of the tail lack black of the tail band (vs. Laughing has full black tail band in first winter bird.)  Rounded head.  Mirror in P10, and white between the gray of the wings and the black of the wing tip.

Laughing Gull:  3 WA sightings, probably moved north with Heermann’s gulls in the fall, one spring sighting.  Kodak 8-9.  Larger bill, longer bill, slight droop in the bill.  Hood smaller than Franklin’s.  Duskier breast and flanks than Franklin’s in most plumages.   Head shape is a longer forehead, not as rounded as Franklins,  one of the few gulls with two complete molts, because it is such a long distance migrants.  The PA molt can be incomplete.    Birds always molt, they can skip breeding, but always molt.   Juvenile plumage is a basic plumage.

Mew Gull:   3 types of Mew Gulls, the Mew Gull, the European Mew Gull, and the Kamchatkna Gull.  (breeds in Siberia, visits W. AK, no WA records)  3-4 year gulls, small bill, no red spot in bill.  Usually first PA 1 molt produces a gray back.    Complex alternate strategy (small gull)  Smaller than Ringed-bill gull.  Adult has yellowish feet, unmarked bill in adult, Kodak 6-7.5.  1st winter, gray back, bi-colored bill, pink legs.  Slowly in the second year the pinkish legs become yellowish.   As with all gulls, there is wide difference in plumage color, i.e. some darker, some lighter, esp. in juveniles.    Wingtip has two mirrors, 9 & 10 and extensive tongue tips in P6-8.    Second winter is adult-like with some distal dark on the bill and less white in the wingtips.   Therefore less black/white checking in the perched bird wingtips.   Common gull is a little lighter, Kamchatka is intermediate coloration, larger and bulkier.  Mew is darker.

Ring-billed Gull:  Lighter in all plumages than CA gull.  Complex alternate.  First winter carpal mark, dark tail tip.  Second winter has dark bill tip.  Very pale mantle and scapulars.  Kodak 4-5.  Adult mirro in 9-10, no tongue tip.  Narrow wings.   Red orbitral ring, pale eye, red gape in breeding birds.

California Gull:  larger than Ring-billed.   First year plumage mimics second year plumage of a Herring Gull.   Kodak  5-7.5.  C Ommon to abundant in winter off the coast of WA.  At least 100,000 California gulls in the fall in WA.   In E WA uncommon to locally common in winter, do breed in E WA.   Both first and second cycles more  heavily marked than the book suggests.   In subadults the bill can have a bluish cast.   Formative plumage has no gray in the back.  Dark eye.   Adult with red and black spot in the bill.  Bill long and parallel edged, with a slight Gonydeal angle.

Small white headed gulls vs. Large white headed gulls.

Primaries 1-6, i.e inner primaries.  If these feathers are brownish they are 1-2nd year birds.  If they are grayish they are 3-4th year birds.

Herring Gull: Kodak 4-5 i.e very pale.  Uncommon to locally common W WA, fairly common to common in E WA.  Split from Thayers in 1972.  Mostly at coast and off shore and Straits of Juan de Fuca.  ( so around here not many seen)   More often on fresh water.  on the East Coast two mirrors, West Coast usually a  mirror only on P9, in spring some have yellow legs,  and the eye turns yellow in the second cycle.  Some can have flecking in the iris.  Juveniles tgher are basically two plumages, first 2 years look like a juvenile, then the 3rd year plus look like adults.   Note pale inner primaries in first and second winter birds.  Bill is large with a fairly large Gonydeal angle, looks fierce.  Flat head, long forehead, often a bump at the back.   Adult winter,  discrete streaking on the neck,  wing tip black from below vs. Thayers is light from below.     Vega  type Herring gull, no WA records.


Thayer’s Gull:  Inland marine waters, to the Straits, also NW WA, Rare in E WA.   In subadult the whole underwing is pale.  In adults the underside of the wingtip is light.   Neck in winter has indistinct streaking.  Orbital purple red, dark eye.  Upperwing has large windows and several tongue tips, making the wing tip whiter overall.

Thayers- Iceland- and Kumliens are all very closely related.   All small bill, pale eye,

Iceland Gull:  8 records thru 2000.  4 E, 4 W WA.   Always pale wing tips, long primary projection.   Tail falls at P6-7.  (vs Glaucous gull with shorter primary projection)

Kumlien’s Gull, no WA records.  Intermediate between Thayer’s and Iceland.

Glaucous Gull:  big gull, long sloping forehead, fierce looking.   Rare to locally uncommon migrant and winter visitor.  Annually about 8 W WA, and 4 E WA.   Occationally small groups in migration.  Almost all seen are first or second year birds.  Moderate Gonydeal expansion.  Relatively parallel bill.   Pale wing tips, not really grayish.  Bill is bicolored, sharply defined.

Glaucous-winged Gull:   Bill si stout, slightly bulbous at the tip (less bulbous shorter Western Gull bill)  Kodak 5-6.  Wing tips Kodak 6-8.  First year bill dark with some pink at the base, second year more pink at the base, eye usually dark occasionally to pale.   Remember we see mostly juveniles and adults.  Fewer other plumages.  Long sloping forehead.    Second winter they get the gray back.  Pinkish orbital, pinkish gape, dark eye.   Juvenile all brownish.

Slaty-backed Gull:   all birds identified have been adults.  Kodak 9.5-11.5, bill stout medium length, parallel with out much Gonydeal expansion.  Very distinct tongue tips in P 6-8.  P10 always a mirror, P9 sometimes a mirror.  Bubble-gum pink legs.    Look like a darker Western gull, black wing tips,  They have a wide skirt, i.e  the edge of the secondaries edged in white.  Seen with the wings folded.   Streaking on the neck, duskiness on the head, (mascara line)  vs. Western gulls with clear white heads.   Clear eye.

Western Gull:  Kodak 8-11, ours are 8-9.5.  The further you go south the blacker the back.  Variegated plumage in the juveniles.  Flat on top head, sloping forehead.  Strong black tail, strong secondary bar.  Third year has no windows on the wingtips.  There are indistinct tongue tips in the sub terminal primaries (6-8)   Bill is shorter than GW, stouter, wider, more bulbous at the tip.   More coastal and on straits,  GW is more inland and to the north.

Lesser Black-backed Gull: 3 records.  Kodak 9-13.   Streaked flanks on young birds.  Adults have yellow legs.  Light eye, long bill, slight Gonydeal angle.     In the east coast a white headed dark backed bull is Greater, a dirty headed black backed is Lesser.

Greater Black-backed:  1 WA record.  One other record west of the continental divide.  Massive bill, the largest gull.  Pink legs.

Heermann’s Gull:  4 cycle gull.  Comes north in post breeding dispersal.   June- Nov mostly in WA, mostly on the coast, some on straits, occasionally in the sound.  All dark gull.  Nothing else like it in our area.   Most of the birds seen in WA have the darker head by the time we see them, but in June-July should have white head.

Continuation of Gull notes from the next Birding class 11-24-09

Ross’s Gull: Complex alternate, Kodak 3.5-4.5, 2-3 year cycle, very small.  Just b arely larger that Boneparte’s  Gull, twice in WA, Adult 1994 E side, 2008 Feb in Tri Cities area.  19 times in the US, 3x in NW, 16 times in NE USA thru 2000.  Stubby short,  some have pinkish tinge is felt to be dietary.  Dark collar is unique in breeding plumage.

Sabine’s  Gull:  pelagic gull, fork tailed.  Tri-colored upper wing, white triangle on trailing edge, Kodak 7-9, a complete pre-formative molt, and incomplete pre-alternate molt, variable depends on feed supply, very rare in E. WA.   Juveniles migrate south prior to molt, so early in season could see brownish individual.  First winter usually not seen in N. America.  First summer partial hood, with dark bill, only adults have yellow tip on bill.  Fall and spring seen off WA coast.  Small, dainty.

Kittiwakes are 3 cycle gulls, go thru first winter in juvenile plumage.

Black-legged Kittiwake:   Note first summer bird has black tip.  Adult with all yellow bill, and completely black wing tips.  Fairly common off shore as a migrant.  Irregular in winter.  Rare to irregular inland.  Rare in E WA.  Kodak 6.5-8.  Pre-alternate molt is variable.  Deep wingbeat, buoyant, lots of up and down flying.

Red-legged Kittiwake:  8.5-9.5 Kodak, very rare off-shore migrant, declining in numbers, 6 recent records in WA, more sightings recently off shore on pelagic trips.  Darker backed, very short stubby bill, note dark undedrwing.  Narrow wings.

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  1. Pingback: Another Gull ID Trip: March 31, 2012 With Special Guest Affcionado Charlie Wright | ABC Birding

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