KEEPING TABS ON BARN OWLS
The bright lights of Logan, Utah, and Marsing, Idaho, are drawing barn owls from the Grande Ronde Valley.
A banding project that started in 1998 indicates that barn owls from the valley are occasionally leaving for places as far away as Logan in Northeast Utah and Marsing in Southwest Idaho.
"I'm surprised at how far some of them are traveling,'' said Scott Findholt, a research biologist with the Oregon Department of Fish and Wildlife.
Findholt is conducting the banding project as a hobby with the help of Jim Ward of the Grande Ronde Bird Club. To date, Findholt and Ward have attached bands, provided by the U.S. Fish and Wildlife Service, to 580 barn owls.
Twenty bands have been returned. Fourteen were from the Grande Ronde Valley, three from the Pendleton area and one each from Vale, Marsing and Logan.
Prior to the start of the study, it was not known if barn owls in the Grande Ronde Valley ever left the area.
"We now know that some are dispersing,'' Findholt said.
It has not been determined if the birds leaving the valley are returning.
"We don't know if they are migrating,'' Findholt said.
Fortunately for Grande Ronde Valley farmers, it appears that the vast majority of barn owls are staying here. Barn owls are one of farmers' best friends because of the remarkable number of rodents they eat. Rodents damage farmers' fields and crops.
The barn owl boxes Findholt and Ward are examining reveal that field mice, also known as voles, are flourishing in the Grande Ronde Valley.
"Mice are stacked like cord wood in the barn owl boxes,'' Ward said.
Indeed, so remarkable are barn owls at hunting field mice that Wyoming Wildlife magazine refers to them as "one of America's most impressive mousetraps.''
Barn owls hunt rodents by listening for them. Their ability to locate prey by sound is among the most accurate of any animal tested, Findholt said.
He noted that the owl's hearing apparatus allows it to plunge into meadow grass to catch small rodents.
Barn owls are also aided by a physique that allows them to fly quietly. Animals can't hear them coming.
Barn owls have large wings for their body size. They can fly quietly since they don't have to work hard to stay airborne.
"They are very fluid and float,'' Ward said.
Barn owls can almost fly like short-eared owls, which resemble butterflies in flight.
By comparison, birds like pheasants, geese and wild turkeys have more weight in proportion to their wing size. The higher wing load means they are noisier.
Ward and Findholt go into nest boxes to get the barn owls they band. Ward said he has never been attacked by an adult barn owl when he's gone into a nest box.
"They try to get away,'' he said.
The young, though, have grabbed him with their feet.
Findholt believes Grande Ronde Valley farmers could make a dent in the vole population by putting up more barn owl nest boxes.
"They could make an impact,'' Findholt said.
Barn owl boxes are critical because without adequate nesting habitat, barn owls must put their eggs and young at risk. They are forced to use flat boards on narrow ledges. The bird's eggs often fall from these perches.
Habitat for barn owls has been on the decline in recent decades. One reason is that there are fewer cottonwoods with cavities in which barn owls can nest.
Barn owls using nest boxes prefer those mounted inside barns. However, they will use boxes mounted on the outside of any building, on large trees or on poles. Barn owls prefer open meadows or fields to hunt, so if the surrounding habitat isn't suitable, the birds will not likely be attracted to a box.
"Barn owls tend to avoid timbered areas,'' Ward said.
Barn owls sometimes nest in the openings between haystacks, Findholt said, and may be found by ranchers when they move hay. Often they move the barn owls to another site or leave the nests alone until the young have fledged.
The Grande Ronde Valley has more than 200 barn owl nest boxes thanks to the Grande Ronde Bird Club, which made most of them. People interested in building their own nest box should contact Ward at 963-6977 to get blueprints or other information.