svehla@zeus.unomaha.edu (11/17/90)
I'm looking for any information from people with hands on experience with identification of 1st year Lesser Black-backed Gulls (as opposed to Herring). I'm here in Nebraska with one bird that is presenting some problems. I've got all the books, so I'm looking for some subjective responses. Any help will be appreciated.
jhiggott@axion.bt.co.uk (jeff higgott) (11/20/90)
1st year Lesser Black-backed Gull:
Look for the following characters:
. Slightly smaller than Herring (_smithsonianus_ Herring is a big bird, about
the size of Glaucous) and more elegantly structured, with rounder head
(Herring is more flat-crowned).
. Lesser Black-back appears to have a more attenuated rear end when
perched/swimming (due to relatively longer wings or primary projection
beyond the tertials?).
. Bill all dark, (paler based on Herring).
. Wing pattern:
Primaries uniformly dark (inner primaries paler on Herring)
Secondaries uniformly dark; greater-coverts dark with paler tips
Thus Lesser Balck-back shows a double inner wing bar on open wing.
_smithsonianus_ Herring Gull shows paler greater coverts, and therefore
doesn't display the obvious greater covert bar.
. Lesser Black-back shows an obviously pale rump (darker barred in
_smithsonianus_)
. Also shows blotchy dark underparts (relatively uniform in _smithsonianus_).
. Shows coarse undertail barring (less obvious in _smithsonianus_).
Hope this is of help. If not, mail me.
Note - these features apply to first winter birds, and are not all appropriate
for separating Lesser Black-back from the European subspecies of Herring.
* Jeff Higgott
- "Ask a stupid person and you'll get a stupid answer" - F&Lgrp@Unify.com (Greg Pasquariello) (11/21/90)
> I'm looking for any information from people with hands on experience with > identification of 1st year Lesser Black-backed Gulls (as opposed to Herring). > I'm here in Nebraska with one bird that is presenting some problems. I've got > all the books, so I'm looking for some subjective responses. Any help will be > appreciated. Hope this reply isn't too late, but I just received the article... I've found a number of lesser black backed gulls, in various plumages, so maybe I can help. All comments below reflect the field marks of a first year plumage. First off, the best way to id an LBB Gull is to not only look at it's field marks, but to compare it to the gulls around it. Make sure you are comparing it to a Herring Gull though, and not another LBB :-). As far as structure goes, the LBB is a _slightly_ slimmer bird than the Herring Gull, and has a smaller head. The bill is shorter, but not much slimmer, so gives a slightly more stout appearance. In herring gulls, the base of the bill is pinkish or yellowish (not always extrememly evident), while the LBB's bill is solid black. Also, the wings are longer. Grant's book mentions that this produces a visible attenuation when perched, but I've not been able to discern that very well. In flight however, it is very obvious, and I've found a number of LBB's by noticing the gull with the unusually long wings. Plumagewise, a crucial field mark, especially in flight, is the dark greater coverts (these are the feathers that lay over the secondaries). In herring gulls, these feathers are pale, with dark, well-notched centers. The overall effect is that they are (usually) paler than the secondaries. In the LBB, on the other hand, the greater coverts are more solidly dark with pale edging. This gives a darker wing in flight, and when perched these coverts are more similar to the primaries in color, than on the herring. In a perched bird, the LBB's tertials are much darker than the herring's. Although not visible in flight, I have found these to be an excellent field mark for flocks of gulls standing about. In flight, the dark tailband is often more well defined than on the herring, owing to the cleaner white rump, and the more solidly dark band. Although these field marks are by no means exhaustive, I hope they help. As I said, the main thing is to compare carefully to the birds around it. Many times, gulls do not clearly show all of the field marks that they are supposed to, but their structure is always distinctive, if you know what to look for. Usually, comparative study will turn up the structural differences much more readily than if the bird is studied in isolation. So look for a slighter bird, one with longer wings, and a smaller head, and look also for more uniformly colored wings, especially in flight. Good Luck --- Greg Pasquariello Unify Corporation grp@Unify.Com
grp@Unify.com (Greg Pasquariello) (11/21/90)
In article <1990Nov20.085010@Unify.com>, grp@Unify.com (Greg Pasquariello) writes: > Hope this reply isn't too late, but I just received the article... > > I've found a number of lesser black backed gulls, in various plumages, > so maybe I can help. All comments below reflect the field marks of > a first year plumage. I apologize for the formatting of that article. My newsreader isn't yet working quite right. ;-( --- Greg Pasquariello Unify Corporation grp@Unify.Com