Excerpts from Jim Conrad's
from the March 17, 2008 Newsletter written in the community of 28 de Junio, in the Central Valley 8 kms east of
Pujiltic, Chiapas, MÉXICO
about 800 meters in elevation, ± LAT. 16° 18'N, LONG. -92° 28'
WARBLERS AFTER A COLDFRONT
Last Thursday a cool front passed through (still got into the lower 90s) so I wondered whether a birding walk after such a front might yield more migrant warblers than usual. That's sometimes the case during spring migration up North.
In a certain acacia at one time I saw a Magnolia Warbler, a Black-throated Green Warbler, a Nashville Warbler and a Black-and-white Warbler, all silent except for the Magnolia, who was chipping but not singing. In the bushes nearby a Tennessee Warbler was indeed singing, not very robustly, but unmistakably. A few minutes later as I passed a shadowy thicket up popped a silent Yellow-throated Chat, the first I've seen here. Earlier in the same place I'd spotted a Kentucky Warbler, skulking and not making a peep.
All these species overwinter here but until now I've not seen them so conspicuously and vigorously foraging, even at 10 AM which is when I saw them. Usually by that late in the morning the overwinterers are quieting down as the heat builds and builds.
Definitely that day our overwintering warblers were friskier and eating more than usual, getting their bodies fat and strong in preparation for the flight they'll be embarking on pretty soon. Curiously, the next day when the usual heat and humidity returned I walked the same route but didn't see a single species mentioned above, though an overwintering MacGillivray's Warbler was present.
On the previous day had I witnessed a mixed-species wave of warblers passing through, or where they all there on the second day as well, just laying low because of the heat?
Whatever the case, you folks up north should be getting your field guides and binoculars ready because warblers are definitely stirring down here, at least sometimes! And that Tropical Mockingbird I've mentioned now sings lustily well into the late-morning heat. The first cicadas also have begun their droaning.