Wintering and Conservation
	In the species treatments we have placed information on the wintering range of North American birds under the CONSERVATION heading. The connection between wintering range and conservation is emphasized because the greatest threat to the preservation of many North American birds occurs south of the U.S.-Mexican border. At current growth rates, human populations in tropical America will double in the next 30 years, and remaining areas of undisturbed natural environment will be greatly reduced. Especially critical for North American migrants is the likely decimation of tropical rain forests, which host many of our songbirds. If current trends continue, those forests will be largely gone before the middle of the next century, in part because of a desire by North Americans for cheap fast-food hamburgers, TV dinners, and meaty dog food. Many rain forests in Central and South America are being cleared so that they can be used to raise beef cattle. Grazing is poor to begin with, and usually in less than a decade new range becomes wasteland. Even so, large landowners make a handsome profit in the process, selling beef raised relatively cheaply to rich nations. In addition, numerous shorebirds depend upon tropical estuarine and other wetland environments either for wintering or for resting habitat during migration. These areas also are likely to be destroyed as the numbers of people expand. And, finally, the use of those pesticides dangerous to birds is not well regulated in most Latin American nations. Some of our birds doubtless never make it back, or suffer breeding failures when they do, because they were poisoned. In short, much of the winter habitat required by some members of North America's avifauna is likely to disappear or be contaminated in the next few decades. Outlining the south-of-the border winter distribution of each species both gives a clue to its vulnerability and provides a reminder that conservation of many of our bird species requires steps to save tropical habitats. Preservation of birds gives us one more reason to do all we can to help our southern neighbors solve their environmental problems. Of course, we must remember that our avifauna, both migratory and nonmigratory, is also threatened in diverse ways by environmental changes within the United States and Canada. SEE: The Decline of Eastern Songbirds; DDT and Birds; Metallic Poisons. Copyright ® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl Wheye.