Excerpts from Jim Conrad's
from the December 11, 2006 Newsletter issued from Sierra Gorda Biosphere Reserve, QUERÉTARO, MÉXICO
SCRUB EUPHONIAS IN THE MISTLETOE
These mornings when I arrive at Biosphere Reserve HQ a little after dawn usually I hear high-pitched, rather tentative and shy bird-peeps. If your computer can digest WAV files you can hear them yourself at http://www.naturesongs.com/sceu2.wav.
The calls emanate from Sweet Acacia trees, ACACIA FARNESIANA, which grow abundantly on the slopes around Jalpan, just as they did in the northern Yucatan scrub. The Sweet Acacias are flowering now, their tiny mimosoid blossoms clustered into orange, spherical inflorescences about the size of large peas, on the ends of peduncles about 3/4-inch long. You can see this wiry little tree at http://www.floridagardener.com/FLNatives/acaciafarnesiana.htm.
At first I thought the peeping birds must be chasing insects among the acacia's flowers but the binoculars showed that BB-size, orange, succulent mistletoe fruits were being sought. Our acacias are heavily parasitized by mistletoes, and our main mistletoe species produces gummy fruits similar to North American mistletoes, except that they're orange instead of white. The fruits are so juicy and pretty that I ate a couple before I remembered that fruits of our North American species are regarded as poisonous. Well, you'd have to eat quite a few before getting sick.
Through the binoculars I could also see who the birds were. They were four to six chubby-looking, smallish birds with thick beaks and black and yellow plumage, reminiscent of northern male Goldfinches in nesting plumage. They were Scrub Euphonias, which you can see at http://www.bafrenz.com/birds/Belize06/ScEuX01.htm.
These pretty little birds occur from Mexico to Costa Rica and they're fairly common. I do find them in scrub but also two months ago they'd sometimes flit around my breakfast table at Ek Balam in the Yucatan. I've also seen Scrub Euphonias on rather humid but weedy mountain slopes, so the species is somewhat flexible in its habitat requirements.
We also have Yellow-throated Euphonias here who are very similar, except that their throats are yellow instead of black. I find this species more in the scrub however. Looks like they'd have called this one the Scrub Euphonia.
Taxonomists have had a hard time figuring out where euphonias belong on the evolutionary Tree of Life. When you want to know how an animal is classified scientifically a good place on the Web to go is to the University of Michigan's Animal Diversity Web at http://animaldiversity.ummz.umich.edu/site/index.html.
When I plug the Euphonia's scientific name, Euphonia, into the search box there I'm led to a page placing them into "Family Genera Incertae Sedis." That's a fancy Latin way of saying "Genus-position uncertain." Tanagers also appear here so neither is their ancestory known. One of my field guides refers to euphonias as "stubby little tanagers."