www.gull-research.org

hi all,

there has been a mixed pair of this combination in frankfurt am main in summer 2009 that has successfully raised one chick.
i've been sent 4 pics of a 1st winter gull (photographed today in frankfurt by stefan stübing) suspected to be the offspring.

i have replied that to me it basically looks like a YLG but 2 details: head shape with small eyes placed high and towards the front and strong inner primary window reaching up at least to p7 could be a hint to marinus. what's your view? and: do you know of any preceeding documented cases of this hybrid combination - any pics?

cheers,

lou

Well well, the next possible hybrid combination...

I have received a few more pictures of this individual from Thomas Sacher. This includes a picture of the bird at the age of 37 days (originally posted on http://www.hgon-birdnet.de/).

Hello!

To clarify the situation a little bit I have to correct two mistakes:

1. The pictures were not made by Stefan Stübing but by another photographer.
2. The 2nd picture posted by Ruud shows a 1st-winter Herring Gull (Larus argentatus), which was included only for comparison. The first picture was taken by Ingo Rösler on 26.06.2009.

Greets
Thomas Sacher

Hello!

The main question here is whether the bird in Lou's post is the same one as the one in Ruud's post (first picture).

The bird depicted on the first picture in Ruud's post shows a hybrid GBB- X YL-Gull (marinus X michahellis) in juvenile plumage at the breeding area in Frankfurt am Main/Germany. All the photos in Lou's post show a gull which maybe the same hybrid in first-winter plumage or simply a YL-Gull. They were taken in Offenbach, only a few kms away from Frankfurt.

Therefore we have got (an almost sure) juvenile Hybrid GBB- X YL-Gull (first pic in Ruud's post) and a potential hybrid in first winter plumage that may be only a normal YL-Gull (pics in Lou's post).

In my opinion the finer barring on the coverts of the juvenile bird and probably also a different tertial pattern compared to the first-winter bird suggest that they are different birds. If this is true the first-winter bird will surely be a normal YL-Gull. So, what do you think?

YL-Gulls are regular breeders in Frankfurt am Main and occur there all year round. GBB is a rare visitor in this part of Germany, but one individual stayed there from May 2008 onwards and finally paired (in its 5th calendar-year) with a female YL-Gull in 2009 (http://www.hgon-birdnet.de/). That's how the story started...

Greets
Thomas Sacher

Hello!

The mixed pair of marinus and michahellis also bred in Frankfurt am Main/Germany this year. A photo of the only chick can be seen here:

http://www.hgon-birdnet.de/birdnet/data/pics/09381.jpg

The bird was ringed with a metal ring at least. Unfortunately there were technical problems with the colour rings...

Tom

You should double-check, if the chick is a real hybrid. Mixed pairs must not produce a "mixed result" in any case, because there exist the possibility of extra-pair-copulations. I remember such surprises between Blackheaded x Med-Gull.