Saturday, 23 October 2010

Caspian Gull (Larus cachinnans), ad, 20.10.2010, Lakolk Strand, Rømø (#1)

It has a good cachinnans jizz with high push up breast, flat belly slightly dropped behind legs. Additionally the upperparts are slightly darker than on nearby argentatus

The bill is relative long and without pronounced gonys angle. On the yawning gull the bare part colour in the opened bill was spot on for cachinnans being orangey-yellow at the base of the mandibles where the skin colour in michahellis is typical blood red and light pink in argentatus

The longer tibia compared to argentatus is quite distinctive

The small eye is situated more frontal because of the flatter forehead than in argentatus and the eye colour is relative dark with a slight green peppering in the iris – most easily seen when light hits the eye directly - and when seen at some distance it stands out as being dark in contrast to argentatus. There is a thin red orbital ring seen at close range

In the stretched wing the grey tongues on the outer primaries are obvious when seen from underneath and the black on primaries creates a classic cachinnans boomerang. On p5 there is a broad black band and the white apical spots are all relative small

It is the one with stretched wings standing in the left half of the photo. The distinctive black feather shafts on the outer primaries in the upperwing are commonly seen in adult cachinnans. There is another 4cy Caspian Gull standing to the right with white summer head, thick neck and strong head profile, possible male

No comments: