Passerines on the Flats
ByIt’s easy to think of the lower Santa Cruz in winter as “just” a raptor playground. But all those falcons and buteos and birdhawks and owls wouldn’t be out there if there weren’t a lot of food on the fields. Large insects, small mammals, and the odd insomniac lizard keep our wintertime birds of prey well fed. And some of those tasty prey items have feathers, too.
There are several “specialty” passerines to be looked for on a December visit to the Santa Cruz Flats. This is perhaps the best place and the best season for the local and possibly declining Bendire’s Thrasher, a bird that can be hard to find otherwise.
Brown, shy, and usually intensely terrestrial, Bendire’s appears to be no great fan of tradition: good sites on the Flats seem to be occupied for two or three years, then abandoned for reasons known only to their toxostomate tenants.
It’s the sparrows, of course, that excite birders most–and help the small falcons sleep warm at night. Gambel’s White-crowned Sparrow outnumbers all other emberizids combined this time of year, but there are good numbers of many other species, among them the demure Vesper Sparrow.
This is a typical wintertime pose, perched on the concrete lining of an irrigation ditch; less typical, fortunately, is the wind, which was blowing steadily yesterday.
The one sparrow everybody wants to see is Interior Sage Sparrow. Just as over most of its breeding range, the wintering grounds are strangely devoid of these birds even where habitat looks, to human eyes, just fine. Yesterday we saw a total of only 6 or 7, the first in a ditch while we were watching Crested Caracaras, the others part of a small flock that has set up hibernal housekeeping in the middle of the Flats. I took this photo there last weekend:
Not only are these gray beauties sparsely distributed and shy, but they don’t stay with us long: obviously eager to get the worm, they’re already moving to the breeding grounds, in northeast Arizona and north, as early as February. Get ‘em now while they’re cold….
