Ecology of Attwater's prairie chicken in relation to land management practices on the Attwater Prairie Chicken National Wildlife Refuge

Abstract

Radio telemetry equipment was used to collect habitat use, movement and survival data on 49 Attwater's prairie chickens (Tympanuchus cupido attwateri) from March 1983-July 1985 on the Attwater Prairie Chicken National Wildlife Refuge. Annual adult survival was estimated between 10.8%, and 35.5%. Nest success averaged 35% for the 3 years of the study. Survival of entire brood units was estimated at 34% 8 weeks after hatching. Annual home range size for females averaged 595 ha, while that for males averaged 360 ha. Male movements were greatest during the early booming period, and least during the summer period. Movements by nonreproductive females were reduced during December-February, increased during the March-May nesting season, and then declined during the early summer months. Of 8 relatively extensive moves by females averaging 3.8 km, 5 were to fallow rice fields south of the refuge. Maximum rate of movement for a brood was 176 m/hour by a 1-2-day-old brood. By 7-10 days post-hatching, hens with broods had moved an average 0.7 km away from their nest sites. Second-year and older burns on loamy grassland areas were selected with the greatest intensity of all habitat types during winter and spring by males and nonreproductive females. A variety of habitat types were used during summer and fall by these birds. Rank correlations of habitat use with vegetation structural measurements taken from transects, and Chi-square comparisons of mean structural characteristics of habitats used to those available, suggested that quality grassland cover with obstruction of vision values in the 2-dm range were important during the critical winter and nesting periods. Eighty-five percent of the 26 nests found during the study were in 3rd-year or older burns. Grazing should be regulated so that clumped midgrass in the 2.5-dm range is available for nesting by the 3rd growing season after a burn. Prior to 15 June, broods used grassland stands typified by 2nd-year and older burns on loamy and sandy areas. After 15 June, broods used more open coarse sand and 1st-year burned areas. Habitats that satisfy all requirements for broods should be well interspersed to reduce brood movements. Data on predator abundance indicated no significant changes in abundance during the 3-year study. Consideration of predator control is not recommended until all other recommended habitat improvements have been implemented.