Birds of Oman

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PLATE 54: LARGE WHITE-HEADED GULLS – COMPARISON PLATE

The plate opposite shows the plumage for a typical adult of the three most confusing ‘large white-headed gulls’ (Heuglin’s, Steppe
and Caspian).
The table below provides comparisons of the adult plumage characteristics, bare part coloration and moult timings of the ‘large
white-headed gulls’, as well as giving additional tips on identification. Care is needed in assessing the upperpart grey tone of
adults, as shade changes with light and angle.

Species Status Back Kodak

greyscale

Leg colour* Bill** Wing-tip (best seen in flight) Helpful tips

Heuglin’s Abundant,

W V, PM

8 –11

(darkest grey)

Yellow Yellow

Some contrast with rest of

wing; small mirror P10 and

usually P9

Fierce face; may keep

head-streaks till early

April, cf. Steppe

Steppe Abundant,

W V, PM

7–8.5 Yellow Often warm,

bright yellow

Between Heuglin’s and Caspian,

smaller grey tongues than

Caspian, subterminal mirror P10,

smaller P9; smaller tongue on

underside of P10

Kindly face; often

dark, bullet-hole eye;

loses head-streaks

by mid-February, cf.

Heuglin’s

Caspian

Uncommon,

pm, wv

4.5–6.5

(palest grey)

Pale greyish-

pink/straw

Long, parallel-

sided, often

greenish at base

Upper: narrow grey tongues into

black; mirror P10 merges with

white tip, smaller mirror P9.

Under: large white tongue on

inner web of P10

Kindly face, long

spindly legs, parallel-

sided wings

Note that in all these gulls males are larger than females with larger bills and a more fierce expression.

• Gulls with yellow legs can, in winter or out of breeding condition, have pinkish legs.
  ** Adults of all species have a yellow bill with a red gonys spot, and all can show black near the bill-tip.

Species Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Mar

Heuglin’s

arrests

moult

Steppe arrests moult

Caspian

starts primary moult continues primary moult

Adult primary moult progression interpreted from Olsen K. M. & Larsson H. (2004) Gulls of Europe, Asia and North America,
Christopher Helm, London.
Note: Northern breeding species moult later than southern species.