April 23, 2014

The Nonsense is in the Details:
A Sparrow Mystery

American Tree Sparrow beak
A couple of months ago, one of my favourite bird bloggers, Rick Wright, wrote a nice article about trying to put words to those features and qualities of a bird, outside of the classic field marks, that allow those almost-unconscious IDs that experts make the instant they see a bird.

I am not one of those expertsyetand I still need to resort to counting off those field marks (sometimes my lips even move) to ensure I've got a correct ID. Some would probably say that looking so intently for these details is holding me back from experiencing the bird more holistically and thus attaining that expert skill level, but I'm sure I'll get there eventually. I've still got the training wheels on my bike, so to speak; I look for those small details so that I'll know them, inside and out, and eventually I'll be able to see them without even looking. And hopefully by then I will have a feel for those un-named qualities too. But for me, right now, it's still all about looking at those minute details.

Burl Ives bird
The Burl Ives of the bird world?
Which brings us to this past weekend when I was once again up at the family compound in the Kawarthas and checking out the action around the feeders. The Purple Finches had thinned out considerably (although there were still a couple of them around), the Juncos were still there in good numbers, and a recent arrival, a fresh and bright White-throated Sparrow (left).

But it was another sparrow I saw that inspired this entry, the same one Mr. Wright wrote about: the American Tree Sparrow. Unlike the newly-arrived White-throated Sparrow, this guy was a late hanger-on into spring soon to be heading farther north to breed. I got some fairly close shots - its fresh, rusty feathers (if that's not an oxymoron) looking fine and ready for the breeding season. I noted the classic field marks all the guide books list: the rust-coloured cap and eyeline, the two white wingbars, the "stickpin" on the breast, the bicoloured bill (yellow on the bottom, black on top). But then I noticed something -- a small blaze of yellow toward the base of the upper mandible, like a blaze on a horse. I had never seen that before. I'd probably never been this close before. Sure enough, it's there in other photos I googled. It's even there in the National Geographic illustration.

Is it just individual variation? Could this be a factor of the birds sex? Do melanin and carotenoid levels alter with molt cycles? I have yet to find any writing that mentions it. Everything I've searched says the same thing: "bill is bicoloured, with black upper mandible and yellow lower mandible." So until I have the time to go to a library, this will have to remain a mystery to me.

American Tree Sparrow beak
American Tree Sparrow beakAmerican Tree Sparrow beak

No comments:

Post a Comment