Wednesday, 5 December 2007

Caspian Gull (Larus cachinnans), ad, 6.11.2004, Lakolk Strand, Rømø

This female-type Caspian Gull has relative long and characteristic thin legs with yellowish colour. Most often when seeing cachinnans the thinner legs with longer tibia compared to argentatus is quite distinctive. The small eye is often situated more frontal and closer to the forehead than in argentatus and the colour is relative dark with a slight green peppering in the iris. The eye in this cachinnans is paler than average, but certainly within their variation and when seen at some distance due to the peppering and the smaller size it stood out as being rather dark in contrast to nearby argentatus. The bill is relative long and without pronounced gonydians angle.

It has a good cachinnans jizz with a high push up breast, flat belly slightly dropped behind legs and long elongated slim rear. Additionally the upperparts are slightly darker than nearby argentatus which was obvious in both overcast and sunny weather.

In the stretched wing the grey tongues on the outer primaries are obvious when seen from underneath, the distinctive black feather shafts on the outer primaries in the upperwing is commonly seen in adult cachinnans, on p5 there is a broad black band, on p10 there is an all white outer tip. The white apical spots are all relative small. In flight the hand appear slender and when seen from the underwing the black on primaries creates a classic cachinnans boomerang

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