The Citizen's Guide to Migratory Bird Conservation
The tools and techniques for bird conservation described in this booklet can be applied to just about any kind of bird. The impetus for this book, however, came from a particular group of birds known as "neotropical migrants." Indeed, concern for these birds is so great that an entire program to conserve them was initiated in 1990. It's called Partners in Flight, and is described on page 5.
What is a neotropical migrant, anyway?
Quite simply, neotropical migrants are birds that spend their summers in Canada and the United States and their winters in Mexico, the Caribbean, Central America and South America (the region known as the New World tropics, or neotropics). Although the name "neotropical migrant" sounds exotic, we're actually talking about common birds, and lots of them -- at least 250 species, nearly one-third of the birds that breed in North America (see the list on pg. 31). These include many familiar birds such as warblers, tanagers, thrushes, and orioles.
Why the concern about neotropical migrants?
Because in recent years, some have declined in numbers. To understand why it helps to know a little about the birds' complex life cycles. First, migratory birds require summer habitat in temperate North America where they can nest and raise their young. Then, during spring and fall they need stopover habitats on their migration routes -- places that are safe to rest in and rich in insects or berries to fuel their long-distance flights. Migration routes run for hundreds or even thousands of miles, crossing numerous political boundaries, until the birds reach their destinations -- the wintering grounds. There, they must identify new food sources in unfamiliar surroundings and compete for food with residents such as White-tailed Trogons and Broad-billed Motmots.
It's a complicated scenario, one that can be easily disrupted by human activities. Indeed, some species of neotropical migrants have shown significant declines. Consider the Breeding Bird Survey (BBS), a volunteer bird-counting effort conducted by about 2,000 birders each June (see page 16). In eastern North America, where some of the best information is available, the BBS suggests that 75 percent of populations of forest-dwelling neotropical migrant species declined between 1978 and 1987. More recently, several of these species increased in number, but some, such as the Cerulean Warbler, have not recovered. And woodland birds are not the only species experiencing declines. Grassland birds such as the Grasshopper Sparrow, which declined 4.5 percent each year between 1966 and 1991, are also in trouble.
Further concern arises from the work of Sidney Gauthreaux, an ornithologist who studies bird migration with radar. His research suggests that the number of birds migrating over the Gulf of Mexico in spring has decreased by half since the mid 1960s.
Let's look at why the declines are occurring.
Greenberg, R., S. Lumpkin, and A. Weissman. 1995. Citizen's Guide to Migratory Bird Conservation, Bonney, R., S. Carlson, and M. Fischer, eds. Cornell Laboratory of Ornithology, Ithaca, NY, USA.
Russell Greenberg and Susan Lumpkin, Smithsonian Migratory Bird Center, National Zoological Park, Washington, DC 20008
Arthur Weissman, Green Seal, 1250 23rd St. NW, Washington, DC 20037
As before, this section has been excerpted in its entirety. Author information and article text current as of 1995.
The content, again, seems timeless, a broad-yet-succinct introduction to neotropic migrant birds. My first thought is much of the content works today as it did in the mid-'90s, though the trends and examples from the BBS should be updated with the most recent analyses. And what about other population studies? Do any come to mind that would be appropriate here? Other thoughts or comments?