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Hard of Herring

November 29, 2007

Back at the museum the gulling goes on. After some difficulty with the Glaucous Gulls I decided to scale back and bull through the museum’s sizable collection of Ring-billed and Laughing Gulls. Both are classic three year birds and in my study I was able to see birds in nearly every plumage of every year. I noted for the first time, the extent of the white tongues on the primaries of adult Laughing Gulls. It wasn’t something I’d noticed in the likely tens of thousands of Laughing Gulls I’ve seen, probably because I tend to overlook Laughers as often as not to my detriment . In his book Sibley notes small white primary tips on the adult birds, but in several birds in the collection the white was nearly as extensive as on Franklin’s Gulls. Something to look for next time I’m on the coast. So it was fresh with the success of Rings and Laughers I took on that ultimate archetypal gull, the Herring.

I got perhaps more than I bargained for. In the time since the museum’s collection began, there have been several taxonomic changes to the Herring Gull complex. What used to be one species with several subspecies is now up to six to eight distinct species based on range more than anything but also subtle plumage differences. Thankfully for me, the birds are identified to at least Herring, so I don’t have to parse it from Lesser Black-backed or Slaty-backed or anything, but still the collection has at least two and up to four distinct species, all labeled as Herring Gull. To see the situation check out the picture below. From left to right are European Herring Gull from the Azores, Vega Gull from the Bering Sea and our good old American Herring Gull from the Outer Banks of North Carolina. These three birds are still considered conspecific as Herring Gull by the American Ornithologist’s Union, but the British organization recently split them into separate species, a decision that the AOU should and likely will echo in the next year or so.

The AOU has, however, accepted the split of one former subspecies into full species status, and I found some of them here in the collection. I suspect that John Gerwin, the curator of birds at the NC Museum expected this split, as the different birds we on a shelf separate from the American Herring Gulls. These different birds were collected on a trip to Germany and differ from American, and even European Herring Gulls in a couple very important ways. For starters, the bill is smaller with a wider gonys, the mantle is darker, but most interesting are the legs.

The bird has bright yellow legs, so yellow in fact, that even in death where the colors of the bare parts tend to fade over time, these saffron sticks are still clearly brighter then the dull tan of the other Herring Gulls. Appropriately, these birds are Yellow-legged Gulls, Larus michahellis, very rare visitors to North America but relatively common in Europe. So I had to change the scientific name to the correct one. Thankfully we write them in pencil at the museum, the better to make changes to tags on something as fluid as bird taxonomy.

And so I managed the adult Herrings, largely due to the fact that leg color is a nice field mark that doesn’t change. But when I started in on the younger birds (thankfully mostly American Herring Gulls) I found this bird that I just couldn’t identify. So I’m asking you, dear reader(s), especially those of you who have experience with European Gulls, cause I don’t. The following pics are of a second-cycle bird that was collected in April of 1984 in Neidersachen, Germany, the same place that the adult Yellow-legged Gulls I had earlier were collected, but a year later so it wasn’t in the same flock. I’m having trouble separating it from European Herring Gull. Any clues as to its identity would be greatly appreciated. Take a look, I’ll catch you at the bottom…

Let me know what you think and why. Next time I’m there finishing up the Herring Gulls, I’ll make the switch, or not, I stumped.

  1. slybird permalink
    November 29, 2007 10:10 am

    Very neat about the leg color of michahellis.

    Regarding your unknown, based on a perusal of the grant and olsen gull guides I would say argentatus. Of course going from a specimen is even harder than a living bird.

  2. November 29, 2007 5:40 pm

    I suspect you’re right. At least, I don’t have any overwhelming evidence you’re wrong… : )

  3. Jochen permalink
    November 30, 2007 11:12 am

    Yellow-legged Gulls Larus michahellis are rather rare (but increasing) and highly localized breeders in Germany (though very common in the western mediterranean region) and have only colonized the country maybe 20 years ago.
    The fact that several specimen were collected in Germany seems a bit unlikely.
    You might want to investigate that a bit:
    were they obtained in Germany as in “collected/shot” or as in “swapped with a German museum”?
    Where in Germany were they obtained?
    In what month were they obtained?
    Can you check on the exact pattern of the wing tip? This is sadly often impossible on museum skins.

    Cheers and happy birding trails

  4. Jochen permalink
    November 30, 2007 11:15 am

    Stupid me: Niedersachsen in the 1980ies.
    Hmmm, I don’t think there were many Yellow-legged Gulls in Niedersachsen back then…

  5. Jochen permalink
    November 30, 2007 11:17 am

    And – finally – your immature bird does look like argentatus, based on the tail pattern and the tertials. The yellow base to the bill is a bit strange though.
    Are you sure the bare parts (on all birds) weren’t painted?

  6. November 30, 2007 11:43 am

    Bare parts were not painted. There are two adult birds I initially IDed as michahellis. I suppose it could be possible that the birds were yellow-legged argentatus, which would be reason why they were targetted for collection.

    I’ll look into the means by which the museum came into the specimens when I go back on Tuesday. I know that were not collected by a museum employee but given by a third party.

    I’ll also try to get a pic of the pattern on the wingtip. The birds are very nicely prepared so there may be a bit of flexibility there.

  7. November 30, 2007 1:13 pm

    I should also point out that the mantle of the possible michahellis was a good deal paler than the labled argentatus. I’ll try to get a picture of that too.

  8. sydney permalink
    May 3, 2008 7:48 pm

    do you kill the birds

  9. May 3, 2008 9:29 pm

    Sydney –

    No, I personally don’t kill the birds, but they are collected by museum personnel for study. It’s a pretty common practice, the idea being that, in a healthy population, a bird that is killed will be immediately replaced by another healthy individual so the population is not harmed in any way.

    The practice of collecting specimens is a contentious issue among some birders, but I am of the belief that a few birds taken for study will ultimately go a long way towards increasing our knowledge and protecting the species as a whole.

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