Making sense of coyote vocalizations
Columbus — Often a bane to rural and urban Ohio landowners, coyotes and their distinctive howls remain music to the ears of scientific researchers.
Scientific findings on coyote vocalizations were highlighted recently in the Natural History of the Urban Coyote, a blog founded by photojournalist Jaymi Heimbuch of San Francisco.
“The coyote is one of the most misunderstood and divisive species on the North American continent,” Heimbuch wrote. “No other wild animal sparks as much emotion in urban residents, running the gamut of loathing and love. But controversial or not, they are here for good.”
Wildlife researchers such as Philip Lehner and Major Boddicker have identified at least 13 different categories of sounds used by coyotes to defend territory, established dens, and announce themselves to other coyotes: growls, huffs, woofs, barks, bark-howls, whines, yelps, woo-oo-wows, lone howls, group howls, group yip-howl, whoops, and yodels.
Columbus-based biologist Karen Hallberg of the U.S. Fish and Wildlife Service studied 19 radio-collared coyotes in central Ohio between 2003-06 as part of a doctoral thesis while a student at Ohio State University.
One downside of the study, she said, was “my coyotes kept getting shot.” In Ohio, there is no closed season to hunt or trap coyotes with a valid hunting license.
During her study, Hallberg said 13 of the 19 coyotes died, mainly due to human activity.
Hallberg studied the coyote group’s yip-howl technique to communicate with other wild animals. Her field research found the yip-howl chorus was used to decide whether coyotes would approach potential rivals or to alert other coyotes to stay away from the perimeter of defended territory. Sometimes, coyotes yip-howled to ward off interlopers from a concealed coyote nesting area, usually in a wood lot within a pack’s territory.
Hallberg said the coyotes she studied set up a “home range” of nine square miles of rural farmland. Within that area, the coyotes would stake out 11⁄2 square miles to establish a den to raise pups, she said.
When Hallberg said she would go into the field to play back recorded sounds of coyotes, such as the yip-howl, she would get a response from the core den area, often set up in wood lots.
“It was a yip-howl territory announcement,” she said. “Nothing sinister.”
What was of interest to Hallberg, she said, was when she played a recorded yip-howl chorus to humans, it was hard for them to tell how many coyotes were involved in the vocalization, which was usually begun by a single coyote, sometimes joined by several, which could last up to a minute.
Also of interest, she said, was when playing back recorded sirens in zoos containing both coyotes and wolves, coyotes would not return the response until after the wolves first responded to the playback from another part of the zoo enclosures.
Hallberg said this behavior was probably because the enclosed zoo coyotes were waiting to determine how far away the wolves were before they felt safe enough to vocalize a response.
In studying coyotes’ yip-howl, Lehner wrote it “may be most important in announcing territorial occupancy and preventing visual contact between groups of coyotes.”
Heimbuch noted researchers have suggested use of such recorded playback of coyote howls to help reduce conflicts with coyotes and indiscriminate killing.
“Coyotes repopulate an area quickly when competition is eliminated,” Heimbuch wrote on her blog.
Hallberg wrote in her thesis that landowners “told me that they and/or their neighbors attempted to shoot coyotes on sight when possible throughout the year.”
Heimbuch wrote much can still be learned from coyotes’ unique, complex vocalization.
“The more we learn about the way coyotes communicate as social predators,” Heimbuch wrote, “the more we can learn about not just their species, but our own as well.”