For the Birds Radio Program: Our Birds in the Tropics
December is when we hunker down for a long winter, thrilling at arriving northern birds that travel down to us, birds like Northern Hawk Owls and Great Gray Owls and Bohemian Waxwings that warm our hearts even if they don’t really fill the place of the many species that abandoned us for the tropics. Some days it’s thrilling to take a long winter walk, and then to come inside and enjoy a hot cup of cocoa while sitting at the window watching our feeder birds.
But sometimes when it seems like the sun will never shine again or the temperature will never rise above freezing, it’s lovely to think about our summer birds and wonder how they’re living down in the tropics, especially if we can block out thoughts of venomous snakes, army ants, a host of predators, poisonous plants and insects, the international pet trade, and deforestation.
Scarlet Tanagers who are so achingly beautiful and dazzlingly vivid up here molt into duller yellow feathers before they head to South America. When I was in Costa Rica one April, I watched migratory flocks heading north—many of these birds were back in breeding plumage, but some still showed signs of molting, so I think most people in South America don’t get much of a taste of their full level of glory. Scarlet Tanagers can look like a bizarre patchwork for weeks before the scarlet feathers win out just as the birds are leaving for the north again. As much as we miss their rich and throaty song all winter, we’re glad that they save their prettiest plumage for us.
Rose-breasted Grosbeaks also molt into boring plumage for the winter. Some go all the way to South America, but a great many stop in Central America and Mexico. In fall and winter they eat a lot of fruits, but switch to primarily insects when they arrive on their breeding grounds, though they take enough seeds that we can enjoy them at our feeders, too. Rose-breasted Grosbeaks aren’t in the same family as Evening and Pine Grosbeaks—those two are true finches who nest farther north and west than here and visit in winter. Neither of them could even imagine life in the tropics.
Baltimore Orioles are in fine fettle down there right now. Up here they’re territorial during the breeding season, but beginning in late summer and throughout the winter they associate in big, convivial flocks, moving about searching for fruit and nectar. Fruit and nectar are patchy—a single tree or a small stand may be laden with abundant fruits with no other fruit for miles. Fruit has a relatively short shelf life—or even twig life—so there’s no point to a single bird claiming a fruit tree for his or her own. And the more birds in a flock, the more eyes for spotting predators and for spotting a new fruit tree when the old one has been depleted. “You are what you eat” is certainly true in the case of sweet-natured, colorful fruit-eating birds. I’ve seen our good old Baltimore Orioles in Costa Rica and Guatemala in the winter, and sometimes they fill a tree full enough to make it look like it was decorated by Martha Stewart. Thinking about tropical warmth can be lovely when the temperatures are in single digits or lower. But those guys will return to us in good time, and there’s no time like the present to enjoy redpolls, northern owls, and other treasures of winter, right here and right now.