Whether melodious, insistent, majestic, or goofy, birds captivate resource managers, researchers, and the public. Since 1968, more than 75% of breeding birds that are restricted to arid ecosystems in the United States, Canada, and northern Mexico have declined. The Great Basin, the largest desert in the United States (> 425,000 km2), is topographically diverse and, among ecosystems in the contiguous United States, one of the least-modified by humans. Therefore, the Great Basin’s potential to provide climate refugia for native species of birds may be considerable.
Realization of this potential will be affected by changes in land cover. As the distribution and density of non-native cheatgrass (Bromus tectorum) in the Great Basin has increased, the extent and frequency of fire in the region has increased by as much as 200%. Cheatgrass-driven changes in fire dynamics are associated with loss of the sagebrush (Artemisia tridentata) and native herbaceous communities in which many native birds breed and feed. Proposed removal of native conifers on as many as 120,000 km2 (30 million acres) across the Great Basin, which largely is intended to reduce fuel loads and increase habitat quality for greater sage-grouse (Centrocercus urophasianus), also may affect the status of hundreds of birds and other species.
Since 2012, researchers supported by SERDP (RC-2202) have worked to develop methods for assessment of species richness and occupancy across space, time, taxonomic groups, and ecoregions. In one of these ecoregions, the western Great Basin, researchers surveyed birds at the Marine Corps Mountain Warfare Training Center, Hawthorne Army Depot, and other locations on the east slope of the Sierra Nevada and in the nearby Wassuk and Sweetwater Ranges (Mono County, California and Douglas, Lyon, and Mineral Counties, Nevada). Twenty-five of the species of breeding birds that they detected in the western Great Basin from 2012 through 2015 are recognized as species of concern by the Department of Defense.
On the basis of their research team’s data and observations, data from the North American Breeding Bird Survey, and the existing ornithological literature, Frank Fogarty and Erica Fleishman (University of California, Davis) compiled a field guide and natural history of the breeding birds on the western edge of the Great Basin. The guide includes photographs of 95 species and short descriptions of each species’ distribution, status and trend, habitat associations, and responses to human activity. The guide also explains how to identify each species by sight and sound and how to differentiate it from other species in the region that may look or sound similar. In addition, the guide notes data gaps for each species that, if filled, would increase understanding of the species’ biology and management actions that might maximize its probability of persistence. A similar guide to butterflies in the western Great Basin will be available by early 2017.
Olive-sided flycatcher (Contopus cooperi). Olive-sided Flycatchers occur in montane coniferous forests, often near edges caused by disturbances such as fire and timber harvest. To many thirsty birders, their song sounds like quick THREE BEERS. Photograph by Erik Enbody.
Yellow warbler (Setophaga petechia). In the Great Basin, Yellow Warblers often occur in thick patches of riparian willow. These small birds aggressively defend their breeding and foraging areas. Photograph by David Pavlik.
Brewer’s sparrow (Spizella breweri). Brewer’s Sparrows are common and widespread in the eastern Sierra Nevada and Wassuk Range. Population declines across the species’ range have been attributed to fragmentation of the shrublands and mixed woodlands with which they are closely associated. Photograph by David Pavlik.
Cassin’s finch (Haemorhous cassinii). Cassin’s Finches build their nests high in conifers. Their songs, which can be difficult to distinguish from those of Purple Finches, often include mimicked notes or phrases of other species. Photograph by Frank Fogarty.