More than 20 years have elapsed since the publication of Birds of the Rocky Mountains, and many changes have occurred in that region’s ecology and bird life. There has also been a marked increase in recreational bird-watching, and an associated need for informative regional references on where and when to look for rare or especially appealing birds. As a result, an updating of the text seemed appropriate, especially as to the species accounts and the technical literature. The following update includes all those species that have undergone changes in their vernacular or Latin names, have had important changes in ranges, or have shown statistically significant population trends or conservation status warranting mention. The accounts also includes six additional species (Eurasian collared-dove, barn owl, gray vireo, northern waterthrush, Scott’s oriole and great-tailed grackle) that have been documented as occurring within the circumscribed Rocky Mountain region since 1986, even if proof of occurrence in one of the parks is still lacking. Nearly 30 of the range maps have been updated as to breeding ranges, and some in-text identification sketches have been inserted where space has permitted.
Available at: http://works.bepress.com/paul_johnsgard/358/