Watchers mapping Iowa’s bird populations

NORTH LIBERTY - The liberally perforated rotten stump did not look all that promising as bird habitat, but Rick Hollis, using a flashlight and mirror to peer inside its most prominent opening, was pleased Thursday to discover a nest filled with baby chickadees.

“That's about as solid a confirmation as you can get” that chickadees nest in Iowa, said Hollis, who will record his find on a computer database that will eventually yield the second Iowa Breeding Bird Atlas, a record of the bird species that nest in Iowa.

Hollis and hundreds of other volunteers, under the sponsorship of the Iowa Ornithological Union and the Department of Natural Resources, are combing through 791 blocks of habitat across the state to identify all the bird species nesting in Iowa. They are in the fourth year of the six-year project.

“The data collected is invaluable to the conservation and management of Iowa birds,” said Billy Reiter-Marolf, an AmeriCorps employee who is coordinating field research for the updated atlas.

The atlases provide a baseline for future comparisons of changes in Iowa's bird life, he said.

The first atlas, completed about 20 years ago, documented the presence of 199 species, 158 of which were confirmed breeding in Iowa.

Subsequent climate changes, as well as agriculture-related landscape changes, dictate the need for the updated atlas, Reiter-Marolf said.

“There will be winners and losers,” said Chris Caster, a former president of the Iowa City Bird Club and a member of the atlas steering committee.

Among the winners, Caster said, will be the bald eagle, which has increased tenfold since the last atlas, and the Henslow's sparrow, a formerly rare grassland bird “that's now showing up all over the place,” primarily because of the expansion of Conservation Reserve Program acreage.

Other winners will include the trumpeter swan, the beneficiary of a DNR reintroduction program, and the sandhill crane, according to Bruce Ehresman, a DNR wildlife diversity biologist. “We didn't document a sandhill nest the first time. This time I anticipate from 15 to 20 nesting pairs,” he said.

Among the big losers are bobwhite quail and pheasants, both of which have suffered population declines because of adverse winter and spring weather, coupled with shrinking habitat, Ehresman said.

Ehresman, who also participated in the first atlas and hopes to participate in the third 20 years from now, said he likes to get out in the morning when birds are singing.

“Sometimes you can hear more than 20 species singing at once,” he said.

Birdsong, while far from the highest level of nesting confirmation, is a good indicator, Ehresman said.

Seeing eggs or baby birds in the nest or fledglings on the ground are among the highest levels of confirmation. Other confirming observations include seeing the nest itself and seeing adult birds carrying nesting materials or food for the hatchlings.

Hollis, who is also participating in his second atlas, said he enjoys the research because it forces him to slow down and observe bird behavior.

Sitting and watching, which is not a part of his bird-watching routine, enabled him to spot adult chickadees flying in and out of the snag hole in which he later found the nestlings, he said.

Reiter-Marolf said volunteers are welcome to help survey the target blocks.

Four Blockbusting Weekends have been scheduled this summer to teach inexperienced volunteers how to participate. For Eastern Iowans, the closest events are June 24-26 at Rathbun Lake in south-central Iowa and July 8-10 in northeast Iowa.