A YELLOW-THROATED WARBLER
IN THE CIBER
Last Monday as I issued last week's Newsletter a
Yellow-throated Warbler, DENDROICA DOMINICA, landed in the ciber's door and hopped across
the muddy, tiled floor to within a foot of my feet. With his yellow throat, white eyebrow
and black mask, his identify was unmistakable. You can see a Yellow-throated Warbler at http://www.birdsofoklahoma.net/Yellow-throatedWarbler.htm.
During my Mississippi hermit days, Yellow-throats were among the first summer residents
to arrive in early spring and all summer they kept high in the pines above my trailer,
their repetitive calls loud and clear throughout the days. At Hacienda San Juan in the
Yucatan they were common and conspicuous high among the fronds of Royal Palms along the
entrance road. And now here was this one at my feet on a muddy floor in a cold, rainy
Pueblo Nuevo ciber.
Could it sense that the entire upcoming week would be cold and rainy, and that it
needed to take unusual risks to locate a dry place?
Back at Yerba Buena I looked up the Yellow-throat's winter distribution. It winters
along the US Gulf Coast and the Caribbean, deep into Central America. A funny thing is
that in Mexico it winters in the hot lowlands bordering the Gulf of Mexico, as well as
here in the Chiapas and Guatemalan highlands, but it avoids the foothills. Why the hot
lowlands and the chilly highlands, but not the middle elevations?
I'll bet the ice ages had something to do with this curious overwintering pattern. A
wild guess might be that the lowland-wintering population results from migration patterns
established after the second-to-the- last Ice Age, while the highland population, to avoid
competition with the lowlanders, became established after the last Ice Age, or vice versa. |
