Some michahellis tertials

Here follows some pix of juvenile Yellow-legged Gull tertials from Lesvos, Greece in July 2009. They are put in order from the least patterned to the most. The first three or four pictures represent the commonest tertial patterns of michahellis.

Complete juvenile HGs

Just for notification there are still a few complete juvenile Herring Gulls in Köping. To the left you can see one of those from the 12th of February. On that day there were two juveniles on the rubbish dump, of 300 birds in total.

Thayeri patterned Herring Gulls

Roughly said, the normal wing pattern of argentatus Herring Gulls is described by black subterminal markings on P6-P10 with well defined white primary tips (on P9 a mirror too). On P10 the white mirror is more often grown together with the white primary tip. This type of wing pattern is shown to the left.


Some of the Herring Gulls show a pattern like the one to the left. Note the thayeri patterned P10 where the white has burned through the black on inner web and combined the white tip with the white on the inner part of the primary. Also on P9 the white has burned through the black on inner web, connectig with the mirror.

Here is another thayeri patterned Herring Gull. Note the pattern of P10 as well as P9. There is only a very thin black line separating the mirror and the white tongue on P9.

According to an article on cyberbirding.uib.no 30 percent of the Latvian inland breeders show long white tongues on P9 and P10 that often connects with the mirror on P9 while 10 percent of the breeders at the coast of the Gulf of Finland do so. Press here to see the article.

On the website of the University of Glasgow, www.gla.ac.uk, it's said that 27 percent of the Herring Gulls from northern Scandinavia and NW Russia show thayeri patterned P9. Here's the article.

Differences in tail pattern of young Herring Gulls

This image shows the normal tail pattern of a first winter Herring Gull. The black bond is broad in the middle and gets narrower towards the sides, with quite a lot of barring on inner part of rectrices, upper tail-coverts and rump.

Some of the Herring Gulls show tail pattern like the gulls on the images to the left and below. A very thin and even broad black bond, with some barring on inner parts. Could recall the one of Great Black-backed Gull.

In this image the tail is really hard to see but it's possible to imagine the tail has the same type of pattern as the one above.