Northern Prairie Wildlife Research Center
Brewster County, Texas
Most important is Big Bend's location on a flyway or migration route between Latin America (South and Central America, and Mexico) and the U.S. and Canada. Additionally, the relatively lush corridor of the Rio Grande is for some species a migration highway through this desert land. Nearly 190 species or 42% of all those recorded for the park pass through as late winter and early spring migrants heading toward northern nesting grounds. In fall, many of the same species return to Latin American wintering homes via the park.
Big Bend is also located where many species' ranges overlap or at their extreme limits. Various birds from the eastern U.S. extend this far west, while others from the western states reach this far east. Latin American species, many of them from the tropics, range this far north (29° north latitude), while northern nesting species may travel this far south to enjoy mild winters. Add to this five habitats (described in the "Key to Habitats" section) that provide food and shelter, and the park's diversity and appeal to birds becomes more apparent.
Surprise is a hallmark of birding here and the park's proximity to Mexico has a profound effect on the occasional appearance of unusual or extremely rare species for North America. For example, 36 species are shared between just the southwestern U.S. species are shared with Central and South America. Some 20 of these species, while having been reported in Big Bend, have seldom shown up anywhere in the United States. Yet, while unusual sightings are thrilling, the park affords everyday species that are often new and equally satisfying to visiting birders. Among the regulars are 62 species that live here year-round, 112 nesters, and approximately 100 that spend the winter.
Water is one of the primary resources needed to support birds of this desert park. In an otherwise arid landscape, its presence, even when limited, greatly concentrates bird life. This oasis effect creates excellent birding opportunities in Big Bend at hundreds of desert-surrounded springs, mostly found in the backcountry and hard to reach, and along the prominent Rio Grande. This riparian or river floodplain habitat is the richest for birds in the whole park. While some species specialize in the dry park habitats, around 75% of all the birds have been reported near water.
Timing is also very important for seeing specific birds or a diversity of species. Spring migration is the most popular period for birding with numerous rare and accidental migrants being reported. It begins the last week of February and peaks during the last two weeks of April and first week of May. During this time, diversity is at its height and Rio Grande Village produces the greatest variety of sightings. Many resident species nest as early as April or May even while the neotropical migrants are just arriving or passing through. While surprises are few in summer, many southwestern United States birds, some tropical species, and a couple of Big Bend specialties can be seen with ease. Although fall migration is less spectacular than spring, it lasts much longer, from August through early December, and peaks twice during that time. One crest that provides good fall birding occurs in late September; another is the first week of December when the migration culminates. Winter is generally mild and species are quite predictable. Look for greater diversity in ducks, shorebirds, and sparrows at this time.
Overall, mild winters, pleasant campgrounds, well-stocked interpretive book shops, and ranger-guided activities make this national park a great place to begin a new hobby or refine hard-won birding skills. Spend several hours to several days at the Rio Grande Village Campground checking the river, cottonwood trees, and desert habitats. Cottonwood Campground, near Castolon, offers similar habitats, but often yields different species. Dugout Wells and the Old [Sam Nail] Ranch are both desert springs that act as hubs of activity for some desert birds. The Chisos Mountains rise in the center of the park to nearly 8,000 feet providing a cooler, moister and more wooded habitat for birds. Hiking trails lead to Boot Canyon, summer home of a Big Bend specialty, the Colima Warbler.
The rewards of birding in Big Bend are many and include seeing migrantssome rare for this areaand many common species closely associated with the desert or native only to the southwestern U.S. and Latin America.