Herding Sparrows for Science

This science feature originally appeared as an article by Edna Weigel, "Herding Sparrows for Science," Mountain View News, Sierra Vista, AZ, March 3, 2004, p. 2. Adapted and used with permission from the author and publisher.

Even experienced birders find it difficult to identify little wintering sparrows running on the ground like little mice or flying away to drop quickly behind a clump of grass. Research Ecologist Dr. Janet Ruth of the U.S. Geological Survey has been studying high elevation grasslands in Southeast Arizona since 1999 to learn more about the birds that spend the winter here.

She uses mist nets to capture bird species that are difficult to identify by other survey methods in the winter because of their cryptic coloration and behavior. After setting up mist nets in the center of an hourglass-shaped plot (7 hectares, or over 17 acres), 15 to 30 local volunteers help conduct the research by lining up 200 meters (656 feet) away and walking towards the net, shooing the birds ahead of them. Birds captured in the net are easy to identify before banding and release. The same people then herd birds from the other side of the nets and repeat the procedure for five other plots at each site. Although other species are captured, Grasshopper Sparrow and Baird's Sparrow are the mist-net target species.

For birds that generally evade mist nets and are easier to identify while flying, one person walks along the transect (a pre-marked 1000 meter line) while two others flush birds by sweeping back and forth from 5 to 20 meters on each side. They record number and species along with approximate distance from the line and then calculate density from those data. Horned Lark, Chestnut-Collared Longspur, Eastern Meadowlark, and Sprague's Pipit are among the species noted along the transects. Vegetation measurements, including height, structure, species and cover are also recorded along the transects and on the mist net plots. Each study site has six mist net plots and six transects.

I communicated with Janet first by email then by phone. She explained she had collected wintertime data from 1999 thru 2001 at seven sites in and near the Sonoita Valley. One of these sites was on the National Audubon Society's Appleton-Whittell Research Ranch near Elgin, 90% of which burned in the April, 2002, Ryan wildfire.

Although researchers prefer designing experiments ahead of time, this chance to study the effects of wildfire in grasslands was too good to ignore. Janet already had pre-fire data and is currently using the same protocols to gather data on a burned site (the research ranch) and on a nearby unburned site (the Bureau of Land Management's Las Cienegas National Conservation Area). She hopes to document vegetation and bird community changes for a few years following the wildfire.

For more information please visit the following Web sites: National Audubon Society Appleton-Whittell Research Ranch and Dr. Janet Ruth's staff page.