Are you bird-watching in Costa Rica for the first time? Well, when you turn to the woodcreepers in your field guide you may get the same sinking feeling that I did when I first came here and say to yourself: How the devil am I going to sort these out?
The recent trip to the Caribbean coast raised questions again, mostly perhaps because we were unsure which of Costa Rica’s 16 species were most likely to be encountered. The field guides make clear that there are 7 of these that can be excluded on the grounds of the normal range of their distribution in the country. Of the remaining 9 the Wedge-billed Woodcreeper (no streaks) does not present any identification difficulty, chiefly because of its short bill, while the bill of the Brown-billed Scythebill also makes it virtually unmistakable. We actually encountered neither of these on the trip.
Above is what seems to be by far the commonest woodcreeper in Costa Rica, the Streak-headed. It’s not a very big bird, being a bit smaller than Costa Rica’s national bird, the Clay-colored Thrush, and it is the one against which all other woodcreepers can be compared and measured. Fortunately, the similarly sized look-alike, the Spot-crowned Woodcreeper (Lepidocolaptes affinis), is a highland bird and thus at Cahuita we could preclude any possibility of bumping into that one. As expected we found several Streak-headeds during the trip. Then came confusion! The following marginally bigger species turned out to be at least as common here:
The loud, strident call of the Cocoa Woodcreeper distinguishes it immediately from the descending trill of the Streak-headed, but if you hear no call you need a good look at the bill of each species to safely distinguish. We also noted that the Cocoa tends to be more placid and not to flutter around as much as the Streak-headed. The generally dark environment of woodcreepers and the muted colour of their plumage may still make identification a problem.
We found this to our cost in the case of the final species, the Northern Barred-Woodcreeper (Dendrocolaptes sanctithomae). Because of poor light and the difficulty in judging size we had a hard time pinning down this one at first.
Most woodcreepers have considerable streaking or spotting but this one merely has fine barring on the underparts. Confusion is then possible with other unstreaked species, principally with the Plain-brown Woodcreeper (Dendrocincla fuliginosa), which we had recently recorded at La Marta, near Pejibaye, and which also occurs at Cahuita. The Plain-brown is much smaller, lacks the barring and has a dark malar stripe. However, if these field marks are not clearly seen it’s easy to misidentify in a dark environment, even though they look so different in the field guides. Both species have straight, black bills but the Plain-brown’s is noticeably shorter if seen well. Here’s a nice shot of a pair taken by John on an earlier visit to the same location:
I hope this brief post brings some clarity and not confusion to a generally bewildering family of birds.