Outdoors: Large-scale effort needed to save grassland birds

Tim Eisele  —  1/23/2008 10:02 am

WISCONSIN DELLS -- Of all of the birds that spend part of their lives in Wisconsin, the group that needs the most help are grassland birds.

Their populations, along with their habitat, are in decline.

That is one of the reasons why the Department of Natural Resources held a statewide Grassland Bird Symposium last week, bringing together state and federal wildlife managers and researchers, and land managers from non-governmental conservation organizations.

"We need to focus in on large-scale, coordinated landscape efforts to help grassland birds," said Andy Paulios, a DNR wildlife biologist who coordinates the Wisconsin Bird Conservation Initiative. "Birds that nest in grasslands are doing worse than any other group of birds. We see serious declines across their entire range."

Some of the top species of concern are the Henslow's sparrow, greater prairie chicken, bobolink, upland sandpiper, sharp-tailed grouse, dickcissel, grasshopper sparrow and eastern meadowlark.

Grassland birds are an important part of Wisconsin's natural history and heritage. About two dozen are identified in the state's Wildlife Action Plan as species of greatest conservation need.

Paulios said that for some species, such as Henslow's sparrow, over 90 percent of the birds are found on private land.

The reasons for population decline are believed to be agricultural intensification, development and succession as trees and brush invade grasslands. Future concerns include invasive species, the nation's energy policies that are turning pasture and hayfields into cornfields, and increased interests in generating wind power and its effect on birds.

Jim Herkert of The Nature Conservancy noted that Wisconsin has been a leader in grassland research, including the late Fred and Fran Hamerstrom who researched prairie chickens on Buena Vista Marsh in the 1950s and research at the UW-Madison Arboretum.

Herkert emphasizes that the larger the grassland the better chance of having species continue to breed and be persistent through time. Smaller patch sizes often see lower nesting success, as the nests are more vulnerable to predators.

The amount of woodland surrounding grasslands also has a tendency to reduce nesting success, probably due to their use by predators.

Researcher Kevin Ellison at UW-Madison is experimenting with removing woody fencerows within grassland fields and preliminary results show it is having a positive effect on grassland bird nesting efforts. Tree-lined rows become predator highways as ground squirrels, skunks, weasels, voles and snakes are major predators on grassland bird nests.

David Sample, DNR grassland researcher, said that the center of most grassland nesting species is in the Great Plains, but Wisconsin does have important areas.

"Probably the two species for which we are most important in terms of being close to the center of the bird's range are the sedge wren and the Henslow's sparrow," Sample said. "Minnesota and Wisconsin are the two most important states in range for the sedge wren."

How much habitat is enough? The state is losing grasslands, agriculture has intensified and now with the ethanol boom, what was grassland is being replaced by row crops.

Sample encourages management on a landscape scale to increase grassland bird diversity in the state. For best results, grasslands should not be disturbed between May 15 and July 15 to allow the birds to bring off broods, and if possible wait until mid-August to mow or disturb grasslands to allow re-nesting and late nesting birds to successfully nest.

Several areas of the state have the most potential for encouraging more grasslands, according to Sample, including the southwestern counties, east-central counties and northwestern grasslands. A large area that has good possibilities for grassland birds is the Military Ridge Prairie Heritage Area around Barneveld. However, increasing pressures for development are converting grasslands to concrete and streets.

"Unless we as a society make a very strong choice to maintain grasslands in Wisconsin, I don't know how we can keep grass on the ground," Sample said.

The best way to retain more grasslands include acquisition through the Knowles/Nelson Stewardship program, renewing the U.S.D.A. Farm Bill, and outright acquisition by Non-Governmental Organizations.

Tim Eisele is a full-time freelance outdoor writer and photographer.

Tim Eisele  —  1/23/2008 10:02 am