Forty-Year Changes in the Avifauna of Grand Teton National Park, Wyoming, with Emphasis on Neotropical Migrants

Abstract

Ornithologists and wildlife biologists have always been interested in documenting long-term changes in bird populations (e.g., Temple and Temple 1976, Kendeigh 1982). Long-term comparisons can assist in identifying patterns of change. These patterns, in turn, provide assistance in defining human impacts that may lead to some species or groups declining towards extirpation. One study specifically (Wilcove 1988) has had a major impact upon current resource issues within the Fish and Wildlife Service. That study used 40-year comparisons to confirm that fragmentation of the eastern deciduous forest had led to declines of neotropical migrants. The Wilcove (1988) study along with an essay (Hutto 1988) and an ecological study in New Hampshire (Holmes and Sherry 1988) were fundamental in identifying that declines in this group of birds cannot be blamed solely upon changes on Latin American wintering grounds. Missing from the neotropical migrant story, however, is an image of how neotropical migrants from western North America have changed in recent decades. An historical data set for comparison is available for seven vegetative associations in the vicinity of Jackson, Wyoming (Salt 1957). This project was begun in 1993 to replicate Salt's 1957 study in Grand Teton National Park. The work in 1993 was a pre-study to evaluate the potential for replicating Salt's study in the mid 1990's, 40 years after the original work.