Living the Scientific Life (Scientist, Interrupted)

tags: , , , ,

[Mystery bird Baltimore Oriole, Icterus galbula, photographed at the east end of Galveston Island, Texas. [I will identify this bird for you tomorrow]

Image: Joseph Kennedy, 16 April 2008 [larger view].

Nikon D200, Kowa 883 telescope TSN-PZ camera eyepiece 1/320s f/8.0 at 1000.0mm iso400.

Please name at least one field mark that supports your identification.

Rick Wright, Managing Director of WINGS Birding Tours Worldwide, writes:

The computer screen and middle-aged eyes give an oddly warm cast to what I know must be the vivid orange of this oriole; but let’s take advantage of that anomaly — not so different, after all, from the sort of distortions we routinely encounter in the field when we see a bird from an odd angle or in poor light — let’s take advantage of that anomaly to focus more closely on the patterns than on the exact colors of this striking bird.

The completely black head rules out a great many Icterus species, but more eloquent still is the tail. Though shadow and an ever-so-slight lack of focus make it hard to tell exactly what color the outer rectrix is, we can see clearly that that feather is yellow or orange distally. For the sake of efficiency, we’ll limit ourselves to the orioles recorded in Texas; we can immediately eliminate from consideration Streak-backed, Bullock’s, Hooded, Orchard, Altamira, Scotts, Audubon’s, and (for good measure, though I don’t think there are any Texas records yet) Black-vented, all of which have black tail-tips in their colorful male plumages.

And that little bit of knowledge lands us right on the correct identification. To confirm our diagnosis of this male Baltimore Oriole, let’s consider the wing. The median coverts are yellow-orange, and the tips of the greater coverts from a discrete white wingbar; white edgings are conspicuous on the secondaries, forming a definite panel.

For a time after 1973, Baltimore and Bullock’s Orioles were treated as conspecific. Though it is true that they interbreed with some liberty (libertinage?) on the western Great Plains, biochemical research has determined that these two taxa are not each other’s closest relatives in the oriole lineage, and they are now considered distinct.

Review all mystery birds to date.

Comments

  1. #1 david skidmore
    November 30, 2008

    Baltimore Oriole? Or is that too easy?

  2. #2 Steve Duncan
    November 30, 2008

    I’m with David – Baltimore Oriole. It has an all black head with orange on the tail. Similar patterned Orchard Oriole has an all black tail and deeper red color.

  3. #3 The Ridger
    November 30, 2008

    Baltimore / Northern Oriole – black head, orange body, black & orange on tail, white on wings

The site is currently under maintenance and will be back shortly. New comments have been disabled during this time, please check back soon.