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Saturday, 1 February 2014

A spectacular rarity, but not without its' troubles


Juvenile Ivory Gull, Cromane, 31st January 2014 (M.O'Clery).

Kerry birders have waited a long time to see this high-Arctic rarity, a species normally associated with feeding on Walrus or seal carcasses on ice floes, or trailing Polar Bears to scavenge from their kills.

Juvenile Ivory Gull, Cromane, 31st January 2014 (M.O'Clery).

This individual has suffered some sort of injury on its' right inner underwing (click the image for a closer view), though it is flying strongly. Could it have been this injury that drove it inshore to find some easy pickings in the form of discarded fish on the beach at Cromane?

Juvenile Ivory Gull, Cromane, 31st January 2014 (M.O'Clery).

Using unique plumage patterns to differentiate between individuals is now a regular feature of high resolution digital photography these days and has been used in a number of cases to detect individuals at differing locations (see the posts below about the recent influx of Kumlien's Gulls for example). However, using the exact pattern of black on the face of this Ivory Gull would be misleading – the black spots would move over time! 

The small black spots above and around the eye on the left side of the Ivory Gull's head at Cromane are actually feather lice. The profusion of lice on this individual might also indicate a bird in less than full health, but it is commonly seen on other vagrant Ivory gulls as well as, eg, some Glaucous Gulls.

Juvenile Ivory Gull, Cromane, 31st January 2014, having a good scratch around the head (Ed Carty).