Female Thick-billed seed-finch

Fine weather continued here in San Antonio today, allowing both garden work and some brief birding.  First arrival was another new species for San Antonio, the Thick-billed seed-finch (Oryzoborus funereus).  I was still bleary-eyed early in the morning when a female (or possibly immature male) crashed into the window.  It was only a little stunned and soon recovered, allowing a brief photo shoot.  The best I could do with my tiny camera is what you see above.

In our area, if you see a small bird on the ground or by the roadside and it’s a seed nibbler, it’s almost always going to be the Rufous-collared sparrow (Zonotrichia capensis) or the Yellow-faced grassquit (Tiaris olivaceus).  The former, with its crest and striped head, is easy to identify, although the juvenile may give the impression of a Song sparrow or Lincoln’s sparrow because it lacks the rufous and has streaks on the breast.   The crest may or may not be raised.

Juvenile Rufous-collared sparrow with crest raised

You can forget about the Lincoln’s and all those other north American sparrows, however.  They are simply not here, despite the recent discovery of a Clay-colored sparrow down at CATIE.  This is a first for Costa Rica, I believe.

The grassquit can present identification problems.  The male is easy, with his pretty, yellow-and-black face, but the female’s face pattern is not so distinct and so you get a small, dull-olive bird that can easily be confused with the females of other, similar species.

The dull female Yellow-faced grassquit

The only other similar-looking species commonly in our area is the Variable seedeater (Sporophila americana), Caribbean race of course.  It is vastly outnumbered by the previous two species.  I find the all-black male virtually indistinguishable from the male Thick-billed seed-finch, and so I have the feeling that some of the male seedeaters I see may well be seed-finches.  I have not found it easy to pick out whether the culmen is straight or curved, which is the principle field-note difference referenced in Garrigues & Dean.  The warm brown of the female Thick-billed seed-finch is a clincher, however, since the female seedeater is very pale.  And if you’re wondering about the White-collared seedeater (Sporophila torqueola), I have seen this species here only in cages.  It is said to have been common in the area years ago but it has been relentlessly pursued for the cage-bird trade.