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Hello Rudd,
no they do not appear to be common, but maybe we are over looking younger birds and there are more than we suspect ? I have seen a few possible 1cy and 2cy the past few winters but they are more difficult to prove. Maybe not many hybrids become adults? If i come across younger suspects this winter i will post here.

derek

Bird 6, 16-10-09, Heemskerk. It may be that some birds actually involve the same individual, although this one was found among Black-headed Gulls in a village. No large gulls to compare to but the mantle was distinctly darker than in Common Gulls.

Ruud,

what are the reasons for excluding Herring Gull in a case like this ?

Last weeks, a bird originally found by Ian is on Surfbirds as Azorean Gull. Now, I was wondering if these argentatus x fuscus hybrid birds can show less prominent streaking in the hindneck, leaving a limited but heavily streaked chin, ear covert area and crown?
And, if Yes; What are the features to separate these two ...

Hallo Peter,

mantle colour. Like I wrote, this bird was distinctly darker than Common Gull, which was also present. Also note the combination of red orbital ring, broad band to P5 and slight yellow cast to the legs (none of which exclude Herring, I know ).

Cheers

Ruud

I suppose Mars - you are refering to this one, unless another one has appeared:

http://www.birdingtoday.co.uk/oxfordshi ... ry_70.html

with some good flight shots here:

http://bluebirder.blogspot.com/search?u ... results=38

JanJ

Jan, that's the one. Presumably safe IDed, but can hybrids be eliminated?

Presumably the right id I woould say to, Interestingly, what would hapen if these to where to mix?

http://www.birdspix.com/Species%20folde ... 1%20cr.jpg

JanJ

Interestingly, today I could sound record the bird above. I came unprepared (from the swimming pool with my son ), so I had nothing with me but my mobile phone. The recordings therefore are in very poor quality. I'm not that good in sound but to my ears it sounds like a cross between a Herring (pitch) and Yellow-legged (tempo, slowing down at the end)!

Long call
Long call 2
Mew call

P7 > P6 but not yet fully grown. The outer rectrices (R4, 5) were still growing.

Have been at the beach of Katwijk yesterday. For long, there was only a small group of 200 birds, but when light faded, a fishing trawler brought in 100's of birds, including 1cy cach, 1cy micha, many lbbg and this bird. Probably a hybrid Herring Gull. Way too dark for northern tatus (which were all over the place) and too light for lbbg. Wrong kind of grey tone to fit micha...

Unfortunately late in the afternoon.