American Crow going to the roost

Photographed at 5:45pm, December 1, 2009. Vigo County, Terre Haute near 10th and Crawford Streets.

 

The following is a recent article from the Dec 1 issue of the Terre Haute Tribune newspaper:

 

Murder mystery: ISU Prof's class counting TH's group of crows

 

By Brian M. Boyce

The Tribune-Star

TERRE HAUTE — If baked crow ever becomes a delicacy, Terre Haute’s in store for an economic boom.

 

“It looks like it will be another 50,000-year, but we don’t know yet,” Indiana State University professor Peter Scott said Monday evening at 10th and Crawford streets, a site he noted was the “old Joker’s Tavern.”

 

Scott’s biology classes began counting the city’s crow population in 1996, documenting the ebb and flow while wondering why the birds choose the city’s rooftops over other locations. Armed with binoculars and clipboards, Scott and students at multiple sites tried to visually group the flying birds and extrapolate flock numbers.

 

Scott himself tabbed 7,000 birds in one five-minute interval, explaining that he judges the space of sky consumed by 100 birds and multiplies out. Another student numbered 570 in the same period before switching off with their partners.

 

Two years ago the count hit 80,000, up significantly from the initial count of 10,000 in 1996. While the numbers are rough estimates, Scott said there is considerable evidence to support a spike in the local population up to at least 45,000 in 2000.

 

Meanwhile, at the boat ramp in Fairbanks Park, Scott’s teaching assistant, Jenny Bodwell, said her group would be there until 6 p.m., “or until we freeze, whichever comes first.”

 

The group reconvenes Wednesday evening for another session of counting crows before number-crunching begins.

 

Bodwell said her primary focus of study is on white-throated sparrows, but over the years she’s become involved in the crow project and finds it interesting.

 

As black spots darted across the sunset, from the banks of the Wabash River into town, Bodwell said there are three theories about why crows cluster on the rooftops of Terre Haute as opposed to trees in the woods.

 

The “heat-island theory,” the “information-sharing theory,” and safety from predators all offer arguments back and forth.

 

The rooftops in town offer islands of heat possibly unmatched in the woods, she said. However, the roosting patterns observed in both the woods and town lead away from that, in her opinion.

 

The idea that crows communicate foraging strategies among themselves is also a possibility she doesn’t particularly support.

 

Safety from predators seems more likely, she said, noting that humans and owls are the crow’s only natural enemies. Crow hunters aren’t allowed to fire shotguns in towns, and the “super intelligent” birds have come to learn this and move to safety, she said.

 

Scott himself said he’s not sure any of the three theories can be completely discarded. The body of research on crows is relatively small, so answers are tough to come by.

 

“They’ve always liked to roost,” he said of crows, noting that groups of 100,000 or more were documented in years prior to the erection of modern towns. “So it’s not a modern phenomenon.”

 

The fact that hunting is not allowed in town is a big plus, he said, but the value of heated rooftops shouldn’t be overlooked. “I don’t know how you rule out those two things,” he said.

 

Kelsey Pearman, a senior majoring in biology, stood in Fairbanks Park trying to visually group the flying crows. “Grouping them together into smaller groups is much easier than singling them out,” she said.

 

Scott said the class will begin compiling the data after Wednesday’s count. How many crows actually exist here always will be a guess, though.

 

“It would be nice to know what it is, but this is just a rough estimate,” he said.

Done