Ring-billed Gull

Larus delawarensis (Ord, 1815)

2017-11-10 Aktau, Mangystau region	© Anna Yasko

Description

Similar to Common Gull, but slightly larger, heavier-bodied, with thicker bill. Adult has pale grey upperwing with diffuse white tertial and rear scapular crescents and trailing edge to the inner wing (in Common Gull, white are contrasting and clean-cut against darker grey upperparts). Wing-tip black with smaller white mirrors on P9-10 than in Common. Bill with solid black bar. Eyes pale yellow (dark on Common Gull). Orbital ring red to orange-red.
In winter, head dark-spotted, typically darker and more densely spotted than Common, strongest on hindneck and around eyes. Orbital ring blackish. Bare parts yellow, generally brighter yellow than in Common (especially in summer). Length 41-49 cm, wingspan 115-135 cm.

Distribution

Inhabits in Northern America, but vagrant birds regularly recorded in Western Europe and rarer observed in Central and Northern Europe.
Single birds recorded on the east coast of the Caspian Sea in Aktau 7th of January and 5th of November 2015; the same bird observed on the seafront of Aktau city from December 2016 to January 2017 (A. Yasko, birds.kz).

Biology

Rare vagrant birds

References

Olsen, K. M. & Larsson, H. Gulls of North America, Europe, and Asia. 1st edition, Princeton University Press, 2004. 103-111