A big flock

Today, the last day of the year, we started on a new site: Laguna del Cochi. The idea here is to visit five different sites, and to describe five different flocks for each site – math wizards among you will have understood that we plan to describe 25 flocks then. Today was flock number 11.

I hate to say it, but the previous two sites, Moxviquil and Huitepec, to me didn’t seem like prime wintering habitat for the Golden-cheeked Warbler. Sure, we registered the species at both sites, but only barely. I couldn't help but feel that these sites were chosen by Pronatura more because they happen to be Pronatura reserves than for being representative wintering habitat for Golden-cheeked Warblers.

Today’s site – not a Pronatura reserve – was different. This was classic pine-oak, and it didn’t take us long to find warblers. I was hopeful right from the start, telling Hector “Wow – this is what they [i.e. Golden-cheeked Warblers] like: pines in the tree layer, oaks in the middle layer, half-open situations here and there… perfect! This is where you expect to encounter the species.”

I grew even more hopeful when the flock we found turned out to be huge – in fact the biggest flock I’ve ever described in three years of my participation in this study in Central America.

The most abundant warbler species in this flock was Hermit Warbler; I counted at least 18 individuals, and feel that this is still on the conservative side. Yesterday I mentioned a study from 1994 in which Hermit Warbler was found to be intermediate in abundance between the locally abundant Townsend’s Warbler and the locally rare Golden-cheeked and Black-throated Green Warblers. Well, Townsend’s Warblers seem to be abundant almost anywhere we go here. But Hermit Warbler, a conifer specialist, is quite rare in oak forests, and I was not surprised to find it in greater numbers at today’s pine-oak site. I remember one flock in Honduras that had a similar number of Hermit Warblers in it.

There was a mini-flock of 15 Bushtits in this flock, and again they went wherever the larger flock went, so to me they seemed totally legit as flock members.

The same cannot be said for a noisy group of 12 Gray-silky Flycatchers (left), which did associate briefly with our mixed flock, but ultimately seemed to be doing their own thing. I didn’t consider this Red Crossbill (right) a flock member either.

After four hours of studying the flock, having identified 76 individuals belonging to 24 different species as flock members, we still had not found a Golden-cheeked Warbler among them. I just couldn’t believe that, kept saying to Hector “there’s gotta be one in there!”

Then, finally, there it was. Again, an adult male Golden-cheeked Warbler. We both had good looks at the bird, and were able to determine it was unbanded.

We also found this caterpillar. I don't think it has anything to fear from a warbler flock, no matter how big.