Herring Gull - 'omissus' type

In my post for Sunday 9th of October 2011, I reported what I thought was a Yellow-legged Gull on the fresh plough along Witch Lane.  Although the bird had mustard yellow legs and a slightly darker mantle than the Herring Gulls it was with...it didn't seem quite right....there was not enough black in the wing tips and the white spots on the primaries were just too large.  There bird also had a bit too much grey on its head for this time of year for a Yellow-legged.

I decided to consult fellow Shenstone birder and local gull guru Terry Hinett.  Terry is one of those hardcore birders who spends day after day wading through tens of thousands of Gulls at the roost at a local Reservoir during autumn and winter.  I sent him my photos and some video footage of the bird and after studying it in detail he gave me his verdict.  It was a (yellow-legged) Herring Gull.  I had never heard of such a thing but I took his word for it as he had seen a number of them over the years.

In the UK we get two races of Herring Gull occur, the standard British one Larus argentatus argenteus and the less common, slightly bulkier nominate form Larus argentatus.  Larus argentatus breeds in Scandinavia and north-west Russia and is often known as a 'Baltic' Herring Gull.  Within the Argentatus nominate race a variation called Omissus can occur where the bird will have yellow legs instead of the usual pink. It appears that the bird at Shenstone on the 9th October was one of these Omissus birds or to give it its full title...Herring Gull (Larus argentatus var. 'omissus')

Phew! I'm glad that's off my chest...it's a right load of old argentatus if you ask me!

Herring Gull (Larus argentatus var. 'omissus')

Click on image to enlarge

For comparison I have attached a photo of an adult Yellow-Legged Gull that I took at Stubbers Green in 2010.  Note the almost non-exsitant white spots on the bird's primaries

Yellow-legged Gull

Click on image to enlarge

A number of other photos of adult omissus Herring Gulls can be seen by clicking on the below link:


  1. Hmmmmmm......think I'll not check the legs of Herring Gulls onmy patch Jase :-)

  2. Thanks for clearing that up mate... got any asprin ?

  3. Interesting stuff, Jason.
    I wonder if there will prove to be any evolutionary advantage in having either pink or yellow legs.

  4. Oh, the minefield of Gull races.

  5. Warren - I wouldn't blame you mate ;-)

    Mark - I ran out of asprin over this one so I had to resort to liquid painkillers (bitter, stout, mild...)

    Bob - thanks, I'm quite pleased with the 2nd photo

    Rob - Interesting point Rob. Apparantly certain colonies of these Herring Gulls in the Baltic regions almost all have yellow legs, yet other colonies only contain a handful.

    Dean - Absolutely...Gull races are a nightmare and something that unless you are a 'Larophile' and watch roosts/landfills regularly always going to be tricky for us lesser mortals!

  6. I'm pretty sure the gull is actually a sub-adult (4cy) Yellow-legged Gull. The tone of grey is difficult to be sure about but judging from how bleached out the Black-headed Gulls are I assume the grey to be considerably darker than in the photo and good for Yellow-legged. The head marking is good for early October both in density and extent and the head-shape is also good. The bill looks bright and deep with the black mark implying sub-adult. The primary moult also looks perfect for Yellow-legged in early October and more advanced than typical for argentatus at this time of year. The white primary tips are large because they are new and not abraded, unlike the Stubbers Green bird which was in July with old, abraded primaries, soon to be replaced. I'm not sure what features point to omissus rather than Yellow-legged and certainly the latter is far more likely in early October.