Effects of Fire on Bird Populations in Mixed-grass Prairie

The mixed-grass prairie is one of the largest ecosystems in North America,
originally covering about 69 million hectares (Bragg and Steuter 1995).
Although much of the natural vegetation has been replaced by cropland and other
uses (Samson and Knopf 1994, Bragg and Steuter 1995), significant areas have
been preserved in national wildlife refuges, waterfowl production areas, state
game management areas, and nature preserves. Mixed-grass prairie evolved with
fire (Bragg 1995), and fire is frequently used as a management tool for prairie
(Berkey et al. 1993).

Much of the mixed-grass prairie that has been protected is managed to enhance
the reproductive success of waterfowl and other gamebirds, but nongame birds
now are receiving increasing emphasis. Despite the importance of the area to
numerous species of birds and the aggressive management applied to many sites,
relatively little is known about the effects of fire on the suitability of
mixed-grass prairie for breeding birds. Several studies have examined effects
of fire on breeding birds in the tallgrass prairie (e.g., Tester and Marshall
1961, Eddleman 1974, Halvorsen and Anderson 1983, Westenmeier and Buhnerkempe
1983, Zimmerman 1992, Herkert 1994), in western sagebrush grasslands (Peterson
and Best 1987), and in shrubsteppe (Bock and Bock 1987).

Studies of fire effects in the mixed-grass prairie are limited. Huber and
Steuter (1984) examined the effects on birds during the breeding season
following an early-May prescribed burn on a 122-ha site in South Dakota. They
contrasted the bird populations on that site to those on a nearby 462-ha
unburned site that had been lightly grazed by bison (Bison bison). Pylypec
(1991) monitored breeding bird populations occurring in fescue prairies of
Canada on a single 12.9-ha burned area and on an adjacent 5.6-ha unburned
fescue prairie for three years after a prescribed burn.