For some reason, the tiny blue and yellow Tropical parula makes me think first of a euphonia instead of a warbler.  Today’s visitor (not the photo above, by kind courtesy of Glenn Bartley and flickr’s Creative Commons) was a very pretty female with a wing-bar that was barely noticeable, and it can serve as a good introduction to this post about the 11 warbler species that I have so far been able to identify here in San Antonio de Turrialba.  The locals call them reinitas.  In many cases, I find them very difficult to identify positively and absolutely.  First, I have to exclude vireos, small flycatchers and even small tanagers, and then I grab Sibley´s wonderful Guide to Birds (North American) because all the migrant warblers are dealt with in exquisite detail there.  All my perusals of Sibley and other authorities still leave me with my one big warbler frustration, a bird I have seen several times.  I’ll deal with that in a separate post.

The Tropical parula is a resident warbler at middle elevations here in Costa Rica, but I have so far seen it on only three occasions, once last year in early November, in January at the beginning of this year, and now, at the beginning of December.  The only other resident warbler that I have identified here in the village is the Rufous-capped warbler, which I saw just once, late October, among some bamboo just up the road to La Cinchona.  Note that this dairy community is not the one involved in the recent deadly earthquake near the Poás Volcano.  The Rufous-capped warbler is a common bird at my friends’ house in San Ramón, but here it is at the eastern limit of its Central Valley range.  All 9 other warbler species here have been migrants.

For the parula,  I had to consult Garrigues & Dean and Stiles & Skutch each time to be sure, because of my unfamiliarity with the bird.  I also want to be sure to exclude the Northern parula, which apparently is a very rare migrant here.  I have seen no warblers here at the house outside migration season.

The other 9 sure identifications, in order of frequency of sightings, are:  Tennessee warbler, Chestnut-sided warbler, Black-throated green warbler, Wilson’s warbler, Yellow warbler, Golden-winged warbler, Black-and-white warbler, Blackburnian warbler, and Hooded warbler.

Here are a few words about each, as far as my experience in Costa Rica, albeit still limited, is concerned.

Outnumbering all others is the Tennessee warbler, which I have now stopped confusing with vireos.  It’s invariably pretty greenish above, sometimes with hints of yellow below.  It seems often to show a thin white edge where the scapulars and coverts touch the breast.  It’s a pretty bird but the drabbest among my visitors.

The Chestnut-sided warbler is also quite common here and is usually very vocal, making a loud chipping sound.  They are invariably in non-breeding plumage, with only a little bit of chestnut on the flanks (occasionally none at all – 1st winter females according to Sibley) but a nifty yellow cap and conspicuous eye-ring.  I have not been able to identify a Bay-breasted warbler, despite its status as common passage migrant on the Caribbean side.  Of course, I could easily be missing juvenile females, or even immatures of other species, because I sometimes catch glimpses of some drab yellowish warblers that then maddeningly disappear.

The Black-throated green warbler appears in fair numbers, but I always have to check carefully to eliminate a possible Townsend’s warbler.  One problem is that the auriculars often seem more strongly marked than in the illustrations in the bird guides, and so I have to make sure that any yellow below the breast is minimal.  That safely excludes the Townsend’s.

The Wilson’s warbler and Yellow warbler always give me trouble.  The former has appeared much more often here so far, and since many of them are females I have to check carefully that there is at least an olive cap.  With the males there is no problem of course.  The Yellow warbler has an easily recognisable resident Costa Rican form that I have never seen, but the migrants that I do see rarely have the obvious red streaks of the adult male.  They often chip loudly and repeatedly.

The Golden-winged warbler is a most beautiful sight, and it was a new bird for me when I first came here.  I have now seen it on quite a few occasions, and I even submitted the dates to the Bird Forum because I read somewhere that its movements in Costa Rica ought to be tracked.  Garrigues & Dean call it fairly common, however, and this seems a fair enough estimate to me.  One of my sightings seems to correspond to a Brewster’s hybrid, according to my field notes, but I always feel less sure of myself with the passage of time.  Females seem to predominate, where the black on throat and auriculars is absent.

The Black-and-white warbler is unmistakable and appears here with some frequency.  It behaves differently, because it tends to creep along branches and tree trunks.

The Blackburnian warbler is next-to-last on the list.  I’ve rarely seen it, but on October 6th, 2008, I had three birds together, one of which was a beautiful, well-marked adult male.

Last but not least is the solitary Hooded warbler which clambered around a low bush in front of my breakfast window on October 20th of this year.  I posted it at the time on this blog.  At first I thought it was a Wilson’s warbler, because the hood was substantially incomplete.  However, it hung around for quite a while, showing its white tail feathers.  It was a life bird, for me, since I had never seen it while living in Texas and California.

Warblers give me hours of pleasure without my even having to leave the house.  I just wish they would show up all year round.  For resident species, however, I only have to climb up the volcano a couple of hundred meters and it’s another world.

A separate future post will allow me to put into print my efforts to identify my ONE BIG WARBLER FRUSTRATION.  Aagh!