At daybreak it was still raining. Clay-colored Robins, White-winged Doves and Great Kiskadees sang all around me while I lay there listening to their songs, raindrops on my tent, and the delighted frogs. It was a perfect Sunday dawn and I didn't want to be any other place on Earth. Then as I was about to doze off again, my reverie was shattered by one of the most bizarre, upward-swinging, jungly-sounding gurgling birdcalls I've ever heard. If your computer eats mp3 audio files you can hear the exact thing yourself at http://web2.uwindsor.ca/courses/biology/dmennill/Mexico/MOORsong.mp3.
I'd heard that song a lot in my life, though I hadn't expected it here, this far north. It was the Montezuma Oropendola, a foot-long, dark chestnut bird with a yellow-fringed tail and, on the male, harlequin face- markings. When you hear its call echoing in a valley filled with mist you get goose-bumps. You can see a male Montezuma Oropendola at http://geometer.org/cr2003web/pages/oropendola.html.
Leaning from the tent I focused my binoculars on the single male perched atop a big snag rising from the reservoir's water not 30 feet away. He was preening in the rain, looking as wet and unconcerned about being soaked as a bird can look, maybe even enjoying it. For 15 minutes he perched there preening and gurgling in the rain.
Oropendolas are closely related to orioles and they build pendulous, baglike nests made of plant fibers just like orioles. However, the nests are much larger, sometimes up to six feet long, and they're colonial, usually all in a single tree, with up to 140 nests per colony. One of the classic, unforgettable images from the neotropical lowlands is that of a gigantic Ceiba tree hung with oropendola nests, such as seen at http://lhostelaw.com/djl/belize/991003be_nesttree.htm.