Thursday, 4 December 2014

Possible 'Baltic yellow legged Argentatus'

I spotted another interesting gull at Shawell recently. It was amongst hundreds resting on the bank between the two lagoons. It looked like a Herring Gull, but it had obvious yellow legs. Unlike the recent probable hybrid Yellow-legged x Herring Gull, I could see no reason to suspect it was a hybrid. It is only a few days ago when talking about the probable Yellow-legged x Herring Gull that I said 'I considered 'yellow-legged' Herring Gull, but I would have liked to have seen a few dark streaks on its head at this time of year'. Well this gull has no obvious head streaking, but I believe it is a Herring Gull. The only thing that niggles me is the squarish head, which is more like a Yellow-legged Gull L.michahellis, but overall this gull feels much more like a Herring Gull.


Putative 'Baltic Yellow Legged Herring Gull'

Its legs are clearly yellow when compared to the pink legs of the nearby ordinary Herring Gulls. It had a longish white tip to P10, P9 had a white mirror split with a black band between the mirror and the white tip and P5 had a small dark mark on it. Its eyes had reddish orbital rings, which were similar to what is shown by adult Yellow-legged Gulls. Its mantle appeared slightly paler than the nearby Herring Gull, but this is not obvious in the photos. It was very bright at the time and the photos have been effected by shadows. Gulls on the bank are always difficult to photograph when the sun is out because until late afternoon you are looking to some degree into the sun.


Many Herring Gulls from the Baltic are said to have yellow legs and are described as having a black sub-terminal spot on P5 in adult plumage.

Below is a photo of the spread wing, although a LBB Gull has got his head slightly in the way and covered the longest primary. A small black spot is visible on P5.

This suggests that it may well be a 'Baltic yellow legged Herring Gull'. These yellow legged Herring Gulls are often referred to as being omissus type Herring Gulls, although the original omissus or Marsh Gull has been spoilt by mixing with ordinary western argentatus Herring Gulls. The omissus bit is now used to point out the yellow legs rather than refer to Marsh Gulls


Putative 'Baltic Yellow Legged Herring Gull'

The more time I spend looking at these gulls the more I see. Hopefully that will result in me finding something really good eventually.

Just after seeing this gull, I found another adult gull, which looked to be a combination of Caspian, Yellow-legged and Herring. Its body shape and wing length matched Caspian Gull, its bill was more Herring Gull like and its legs were bright yellow and its mantle colour was more of a match for Yellow-legged Gull L. michahellis. That one has been firmly dispatched to the no idea section of my mind.

2 comments:

  1. Great post. I found a similar gull on Jan. 3, 2015 in Pubnico, Nova Scotia, Canada. Would you mind taking a look at it?

    http://smg.photobucket.com/user/alixd/library/2015Birds

    ReplyDelete
  2. Hi Alix, interesting gull that one. Baltic yellow legged Herring Gulls are said to have a small dot or no dark markings on P5, but yours has a distinct band. This band is more like what I see on many Yellow-legged Gulls (Larus michahellis), but structurally your gull doesn't fit typical Yellow-legged Gull. It is difficult as you are quite a long way from the home of most European gulls, but we do know that gulls cross the Atlantic from both sides. If I saw that gull here in England I might think hybrid Caspian Gull (Larus cachinnans) due to the bill shape and its small head with what looks like a dark brown eyes. Its leg colour is a washed out yellow as far as I can see and they are quite spindly. The primary pattern is wrong as is the general appearance for cachinnans, but it does have some similarities to some of the gulls I see that are almost certainly hybrids.

    Can you rule out the possibility of it being one of your American Herring Gulls?

    Photos of yellow legged Herrings can be found at:

    http://birdingthedayaway.blogspot.co.uk/2014/11/omissus-herring-gulls-getlini-latvia-21.html

    ReplyDelete