American Birding Podcast



Avian Changes in the West

For anyone with an interest in changing avian abundance and distribution, the Cooper Ornithological Society’s 1994 book A Century of Avifaunal Change in Western North America is a landmark of scientific research and a source of essential knowledge for efforts in conservation.

Twenty years later a similar and even larger volume is planned by Western Field Ornithologists, building partly on that 1994 classic and updating patterns of change between the late 20th and early 21st centuries. It is envisioned as a 400-page book containing about 30 papers to be published as a monograph in WFO’s peer-reviewed Studies of Western Birds series.

There will be no shortage of new patterns and trends to report. For example, in the 1994 volume, the Spotted Owl was noted as decreasing due to logging of old-growth forests, and the Barred Owl was noted as expanding its range westward. Unrealized at that time was the disastrous behavioral clash to come—that the Barred Owl would eventually begin to outcompete the Spotted Owl and drive it away from the already receding old-growth habitat.

Two recent papers in WFO’s journal Western Birds have documented crashes in Yellow-billed Magpie and Tricolored Blackbird populations (studies that will be summarized in the November–December 2013 issue of Birding). Previous articles in Western Birds have told of continuing declines in Yellow-billed Cuckoo, Warbling Vireo, Purple Martin, Cactus Wren, and Yellow Warbler populations, among others. In contrast, papers have noted breeding range expansions by Acorn Woodpecker, Black Phoebe, Least Flycatcher, Eastern Bluebird, Great-tailed Grackle, and others.

Yellow-billed Magpie, photo by Bill Bouton via wikipedia

Yellow-billed Magpie, photo by Bill Bouton via wikipedia

Two further examples come to mind involving downtrends that severely worsened or newly arose since the 1994 compendium:

• The Common Nighthawk was noted in the book as declining only in Alberta. Two decades later, its population has collapsed not only throughout the West but also across much of its central and eastern range as well (Birding, March–April 2013, pp. 26–27). 

• The Oak Titmouse, like the Yellow-billed Magpie, did not warrant mention in the book. Since then, however, its population is threatened by the plague of Sudden Oak Death Syndrome, which destroys the titmouse’s preferred habitat (Birding, September–October 2006, p. 24).

WFO’s announcement of the planned new volume emphasizes its purpose: “Documenting and synthesizing the patterns, rate, and causes of these changes is crucial for the conservation of birds in western North America, particularly in a time of rapid climate change, expanding human population, and accelerated resource extraction.”

Suggested topics include new methods of assessing change, overview of changes in landscape and climate affecting birds, case histories of population change (up or down) drawn from long-term datasets, cause-and-effect studies linking change to natural and/or anthropogenic factors, and regional issues such as changing Arctic ecosystems, and endemic and invasive species in the Hawaiian Archipelago.

WFO is soliciting papers and encourages authors to present them at a symposium during the WFO meeting in San Diego in October 2014. Before preparing manuscripts, prospective authors should contact W. David Shuford (dshuford AT or Robert E. Gill, Jr. (rgill AT about guidelines and suitability of planned  submissions.

Back to the future: In their introduction to the 1994 volume, editors Ned Johnson and Joseph Jehl, Jr. expressed a hope that gaps in knowledge of avifaunal change in the West at that time would someday be filled by future symposia. WFO aims to close as many of those gaps as possible in what should be another landmark volume.