Friday, April 30, 2010

A Weird Oriole at Cottonwood Campground

On Thursday April 29th I was birding with a group at Cottonwood Campground in Big Bend National Park.  It was mid-morning and we were looking over some birds at the group camp site which is located at the east end of the complex.  At one point, a couple of clients asked about the identity of a certain oriole.  I glanced at the bird and initially thought Hooded Oriole.  Distracted by an Ash-throated Flycatcher, I did not spend any time studying the oriole.  Eventually, I decided to photograph since it was sitting out so nicely.  As I focused on it, I noticed that it was not what I had initially taken it to be.  As soon as I took the first exposure, it turned and flew directly away out of the campground beyond some mesquites and out of sight.  Looking at the photo, I immediately had the hunch that this was some sort of hybrid, and the orange that I was seeing in the tail as well as the bill coloration made me suspect that a Bullock's Oriole was involved.  Despite spending some additional time trying to relocate the bird, it was not seen again.

To me, the bird's structure looks intermediate between that of a Hooded and a Bullock's Oriole.  The tail seems strongly graduated, which is unusual.  The photo gives the impression of there being a great deal of white in the wing panel, though I did not notice this in life.  One of the clients specifically commented on how much white there was present.

The bird also somewhat resembles a Streak-backed Oriole, though the tail pattern seems off for that.  In addition, the body was more extensively orange than is typical of northern populations of Streak-backed which tend to be most intensely orange around the head.  I would enjoy getting feedback and insight from others regarding the identity of this peculiar bird.

1 comment:

Alvaro said...

Chris - thanks for posting the photos in a good size. Facebook is pretty poor for photos like this. I could not see the yellow you were talking about on my screen! Now I see it. Bills are very important in orioles, not just shape but pattern. The nearly all blue-grey lower mandible is something you see in "Northern" and somewhat in streak-backed, not in Hooded. "Northern" should have the blue-grey going up onto the maxilla, this does not happen on your bird. This too would seem intermediate between Hooded and "Northern." The white tips to rectrices = Hooded. Bib does look intermediate between Hooded and Bullock's. Yellow on tail is weird, not good for anything, except that Northerns have yellow on tail, but not in a pattern like this. Again intermediate. This may well be a hybrid...but I guess it got away.