Two Pale Herring Type Gulls

Patrick Comins has been making exciting gull discoveries at a small dump just east of Hartford CT. Here are some shots from February 1999 of two (at first) similar looking birds, with Patrick's descriptions.

"When I first found this bird I immediately suspected a first year Thayer's Gull. It was the tertials that first caught my eye. They appeared to have too much internal marking to be a Herring Gull. Upon further inspection nearly all of the marks fit Thayer's perfectly. In fact when you read the section in Ken Kaufmann's Advanced Birding Guide, it almost seems that it is this exact bird that is being described. The only two points that are not right on target are:

1. The tertials may have more internal marbling than is average for Thayer's. Observers very familiar with both Thayer's and Kumlien's however feel that this is well within the range of normal for a Thayer's. [Editor's Note: I agree.]

2. The bill is not entirely black. It is said that most all Thayer's have an entirely black bill well into first summer. Fading at the base of the bill, such as in this bird, is however within the range of normal variation for this species. [Editor's Note: However, by late February a bit of fading like this is quite typical of Thayer's.]

"Images C, D and E show the markedly pale under primary area typical of first year Thayer's Gulls. In flight from below it might be easy to confuse this bird with a Kumlien's. Shot D also shows the upper primary area. This is too dark for a Kumlien's. When viewed more spread the primaries showed the "Venetian blind" pattern that is typical of Thayer's created by the difference between the inner and outer webs of the primaries. These shots do not show the spread tail or secondaries, two other features that rule out Kumlien's. This bird showed the broken secondary bar that is typical for this species and the mostly dark tail(with noticeably paler areas towards the base of the outer three or four feathers. Also note that the primaries are slightly darker than the tertials(A,B), and that the tertials are con-color with the rest of the upperparts. The former feature is anti Kumlien's and the latter anti Herring. Note also the neat pale fringe around the primaries in these two shots, another pro Thayer's and anti Herring feature. All of these features combined with the fact that the features fit Thayer's Gull so well, combined with the structure of the bird led me to call this bird a first year Thayer's Gull."

More photos of this bird (and others by Patrick Comins) are at Angus Wilson's site, http://www.best.com/~petrel/CTThyGull.html.

A	B

C	D	E

Patrick writes:

"I first found this bird on December 21, 1998. On first glance, I thought it might be a Nelson's Gull. I then saw the bill, which was mostly dark, and somewhat small, and noted the small/average(for a Herring Gull) size. I then thought Thayer's Gull, but the bird was not right for that either. The bill appeared to be too pale at the base for a first-winter Thayer's at this time of year, and the tail was too smithsonianus-like. Could a Herring Gull be this pale, and what about those internally marked tertials? A short while later I discovered an obvious Nelson's Gull(also photographed and videotaped). It was nearly exactly the same color in the primaries and tertials. I thought they might have been the same bird till I saw the bill on the Nelson's, and saw how huge the bird was. They landed next to one another at one point. This is when I took picture #1. In this shot, I feel that the color was the truest to life of the December shots. The others may be a bit underexposed. I obtained photos #3-8 between December 22 and 28th. Photo #2 was shot in late January. The colors are fairly true in that one also. (photos of what might be the same bird from March are on Angus Wilson's website).

"At this point I am not sure what to make of this bird. Some have felt that it may be a small Nelson's Gull, I think that is a good possibility. Others have felt that it is a pale Herring Gull, but those tertials don't look right for smithsonianus to me. Still others still feel it is a Thayer's, which I don't feel it correct. Another possibility might be a hybrid smithsonianus X Kumlien's. That should look much like a Thayer's, but has it ever been recorded?"

1	2	3	4

5	6	7	8

since March 16, 1999