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Column: Hawk researcher dedicated to 'birding with a purpose'

Tim Eisele
Special to the Capital Times  —  7/11/2007 12:07 pm

HARPER'S FERRY, Iowa---What attracts a person to work full time conducting research on birds?

Jon Stravers, research and field trip coordinator for the National Audubon Society's Upper Mississippi River Initiative in Harper's Ferry, Iowa, said that the real hook was when he watched a courtship flight of hawks and wondered, "My goodness, what in the world is this?"

"The hawks literally were dancing in the sky and I began studying on my own and I watched that pair of hawks through the entire season, watching them nest, and raise young which fledged," he said.

Stravers had the good fortune to meet Gladys Black, a serious birder who was known as the "bird lady of Iowa." Black lived in Pleasantville and wrote birding columns for the Des Moines Register, and was his first birding instructor.

"She really knew her stuff, and she guided me, and then referred me to Dean Roosa, the state ecologist for the Iowa Conservation Department," Stravers said. "Roosa was a hawk man,' and once I started monitoring raptors and got a taste of the field work, I realized then that this is what I really wanted to do."

He graduated from Central College in Iowa and started the Midwest Raptor Research Fund. He soon decided that he wanted to spend his time in the field watching hawks rather than running an organization. He obtained contracts from the Iowa Department of Natural Resources to monitor red-shouldered hawks in northeastern Iowa, and from the U.S. Fish and Wildlife Service to monitor hawks from Prescott down to Quincy, Ill., a 500-mile stretch of the river.

"This is birding with a purpose, for a species that needs attention," he said. "To go back into some of the biggest forests for the 28th year in a row, with a shroud of fog and bingo find a pair of red-shouldered hawks, my heart responds to that."

He is focusing on the Bird Conservation Area of northeast Iowa which is in the Driftless region, an area including southwestern Wisconsin and northeastern Iowa, that was not covered by glaciers. That's where the birds are most common. It's also an area where foresters would like to see more oak regeneration, because native oaks are being replaced by shade-tolerant maples, and often that calls for clearcutting to simulate the natural conditions of a wild fire that provided sunlight for oak to sprout.

But that also fragments the forest which favors red-tailed hawks, a generalist among the hawk species, and usually discourages red-shouldered hawks.

"Red-shouldered hawks prefer a large in-tact site, and any time you take a chance of opening it up you are shifting the suitability of a site to red-tails rather than red-shouldered hawks," Stravers said.

He emphasizes management for red-shouldered hawks because that will also benefit a host of other species.

"The big question is how much disturbance can a red-shouldered hawk tolerate?" he asks rhetorically.

He believes the key is to keep a large forest uncut. The birds can withstand small tree harvests on the periphery.

"The other thing is timing of the cuts," he said. "I prefer that they get everything done by January 30, so there is no disturbance when the birds come back from the south."

He said a good compromise is to do more burning in a woodland to help regenerate oak rather than clearcutting.

"At one time the species might have been on the brink, but now I get reports from biologists that indicate the birds are coming back to the same territories year after year," he said. "Red-shouldered hawk population declines took place during an era when pesticide contamination caused declines in raptors, but I am now seeing a moderate but steady increase in the number of nesting sites."

Stravers says there is a remarkable stability and diversity of bird populations. "Wherever you save the habitat, the birds will show up," he said. "Populations will change over time, but if you save the habitat -- they will come."

Tim Eisele
Special to the Capital Times  —  7/11/2007 12:07 pm