Sunday, 6 November 2011

Caspian Gull (Larus cachinnans), ad male, 4.11.2010, Feldballe

This large male Caspian Gull male was seen just north of Feldballe on Djursland. The primary pattern and many other characters are spot on for cachinnans, but the eye is much paler than on the classic individual. However, Lou Betalan has several similar pale eyed cachinnans on his excellent webpage “caspian and yellow-legged gulls in Romania”.

This male has paler eyes than the average cachinnans, however, note the extended red orbital in front of the eye.

Note the cachinnans jizz with a push up breast, flat back and slender elongated rear with long primary projection.

The primary pattern is perfect with the outermost p10 having a large white tip and a grey tongue running up the inner web, isolated white mirror on p9 and broad black band on p5.

In flight the hand is relative slender and when seen from the under wing the black on primaries creates a classic cachinnans boomerang.

Note the yellowish legs.

The distinctive black feather shafts on the outer primaries in the upper wing is commonly seen in adult cachinnans and in the stretched wing the grey tongues on the outer primaries are obvious when seen from underneath and even from above.

It has a snow white head without traces of streaks as in argentatus Herring Gull.

The upperparts are slightly darker than nearby argentatus which was obvious in both overcast and sunny weather.


JanJ said...

Hej Kent.

Fina bilder på den kaspiaka truten!
Notera också nästan exakt likartad ruggnings status (moult score) med sölvmågen.



Kent Olsen said...

Hej Jan,

du har ret, fældningen matcher gennemsnitlig argentatus med p10 tæt på, men endnu ikke fuldt udvokset.