Archive for Hybrids and introgressants
East Is West
Posted by: | CommentsA really fun morning with the survey team at the University of British Columbia South Farm here in Vancouver.
There were lots of birds around on a fine spring-like morning, with migrants and summer arrivals well represented–from a Townsend’s Solitaire to numbers of nice bright Orange-crowned Warblers.
The “best” birds from my point of view, though, were two typically eastern phenomena: a fantastic male Slate-colored Junco and a bizarre Northern Flicker introgressant. The flicker, seen only on the ground in the grass (and thus its shafts never visible) had two well-developed red malar stripes, neither with any obvious black, and a somewhat thin but still complete red nuchal crescent. Both were reminders that British Columbia is huge–and that Slate-colored Juncos and Yellow-shafted Flickers both breed in the province, just, oh, several hundred miles north of Vancouver.
The Conscience of a Birder
Posted by: | CommentsWell, rats.
As the breathless tone of yesterday’s entry reveals, I was excited yesterday morning at Jericho Park to find the bird above, which I gleefully ticked off as a Western Gull–or something very, very close to it.
As I pondered, though, the pale eye and, especially, the orange tint to the orbital ring started to worry me. I sent the photos off to a couple of friends with massively more expertise and experience than I’ll ever have with these birds, and the answers came in: Steve said he would have called it a hybrid “but who can really tell,” and Guy agreed, noting among other things that the mantle was too pale even for northern occidentalis.
So this one goes down as a dark hybrid or introgressant, and my search for a pure Western Gull in British Columbia continues.
I now read a different meaning into the bird’s posture.
Jericho Gulls
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Again and again it strikes me how much Jericho Beach reminds me of Mount Auburn–without the dead bodies, of course, and with a much better gull selection.
I don’t have my lists at hand, but I’m pretty much certain that my larid list for the Massachusetts cemetery comprises three species: Great Black-backed, American Herring, and Ring-billed Gulls. Without any of those three, this morning’s Jericho Beach walk produced four species.
Four species–depending on how you count ‘em. Sooner or later I’m going to have to come to terms with the pugetensis problem. Our most abundant gull here in Vancouver is Glaucous-winged Gull, or at least birds that look more or less like Glaucous-winged, with pale upperparts and blue-gray wingtips (whence the name).
An awful lot of those birds, however, have wingtips that are slightly too dark for a classic Glaucous-wing, suggesting that somewhere on not too high a branch in their family tree perches an American Herring or Western Gull. Some of them have primaries so sooty as even to be mistaken for one of those species.
I try to look at such birds when I can, but until this morning hadn’t run across anything overly convincing. Then, while I was watching my first Bonaparte’s Gulls of the spring off the beach, in came this beauty.
When it landed on the pier–in less than ideal light, unfortunately–the dark upperparts and broad secondary “skirt” were obvious.
Those features plus the black wingtip and very bright bill left me satisfied that if this wasn’t a pure Western Gull, then it was at least so near the dark end of the hybrid spectrum as to make its mixed ancestry undetectible.
The bird was aggressive, and I had some excellent comparative views of its upperpart color with the paler mantles of the Glaucous-wings in flight; this, sadly, is the best photo I got of the combination.
Pretty exciting, and a state (uh, sorry: province, eh?) bird for me. Short of putting the blird in a bender and dipping in some litmus paper–or whatever the scientists do–we’ll never know whether miscegenation lurks in its ancestral past, but I found it pretty convincing. [But see here for my later recanting.]
And the day’s fourth gull species? No surprises there: Mew Gull. There are relatively few around right now, but one fine adult was on the first pond with the ducks.
I especially like this picture and the way it shows the smudgy “shawl” on the hindneck, already lost at this time of year on most adult Mew Gulls.
I still don’t have a handle at all on distinguishing these “Short-billed” Gulls from Common and Kamchatka Gulls, though apparently the pale eye is a good indication that I didn’t miss a major vagrant.
More gulls tomorrow, I hope!
An Odd Duck
Posted by: | CommentsIdeas?
I’m puzzled myself. There are a couple more photos here.
January 4, 2010: Kitsilano Beach, Vancouver, BC
Mallard Mixes
Posted by: | CommentsAs if I needed another reason to be looking forward to our return to New Jersey, there were American Black Ducks at every site we visited these past days. I’ve always been more than partial to the species, from the first time I saw it 30 years ago (!) this month.
Fond as I am of the bird, and not getting to see it all that often of late, I spent a bit of time looking through the flocks at Brigantine, at Sandy Hook, and at Etra. As usual, it wasn’t long before we started noticing the “mixes,” birds whose ancestry must have included both American Black Ducks and Northern Mallards. Most such birds look simply like Black Ducks with a green cap, silvery tertials, and variably pale tails–and, this one at least, an apparent fondness for a girl just like the girl….
Others are more striking. Yesterday Alison and I found this bird consorting with American Black Ducks at Etra Park, Monmouth County:
This bird is, obviously, much more Mallard-like, but with dark body plumage and a pale head. If it’s true that female “mallards” of all stripes and taxa prefer the studlier “Northern” Mallard drakes, then this one has a better chance, I’d guess, of reproducing than his Black-ish cousin above.
