Greater sage-grouse (Centrocercus urophasianus) are a species of conservation concern throughout their range including the state of Idaho. Little is known about the size of areas used by female sage-grouse during the breeding and nesting seasons, fidelity of females to those areas, or fidelity of female sage-grouse to specific leks or nest sites. The recent miniaturization of global positioning system (GPS) transmitting devices allows for a more thorough analysis of this behavior. We placed GPS transmitters on 234 female sage-grouse in Idaho, USA, from 2015 to 2019. We monitored 145 nest attempts, 15 of which occurred in consecutive years, from 130 female sage-grouse (Centrocercus urophasianus) with GPS transmitters to document movements and space-use during nesting. We quantified the length and direction of off-nest excursion distances for all 145 nest attempts. Also, for the 15 consecutive nest attempts, we compared the excursion distances for each bird, each year. The mean distance for an off-nest excursion across all study areas was 93.7 m (n = 145, SD = 57.9, range = 15.5 to 275.8 m). Rayleighâ€™s test of uniformity indicated that eight of 145 nest attempts had off-nest excursions that were not in a consistent direction. Mean excursion distances in the consecutive year were longer than those of the initial year (T = -3.1, n = 15, p-value = 0.013), and females with smaller excursion distances in the initial year also had smaller excursion distances in the consecutive year. We also quantified size of breeding areas for 50 female sage-grouse and identified factors that influenced breeding-area size. For 18 of those females, we quantified size and fidelity to breeding areas and leks between successive years. We generated 95% brownian bridge estimates of breeding-area size for each bird and counted the number of leks those females visited. To quantify breeding-area fidelity for the 18 females, we overlaid 95% brownian bridge estimates for females with consecutive breeding attempts, calculated percent overlap, and documented number of leks visited each year. Median size of breeding areas for all females was 21 km2 (interquartile range = 7.8 to 59.3 km2). Each bird visited a mean of 2 leks (SD = 1.2, range = 1 to 6 leks). Between years, breeding areas overlapped for all 18 females, and size of breeding areas did not differ between the first and second year (W-value = 61, p-value = 0.49). For those 18 females, only 7 visited the same lek in consecutive years, and none visited more than one common lek in consecutive years. Our results indicate that females use large areas while breeding and nesting and exhibit strong fidelity to those areas. Our results provide novel information on the breeding and nesting ecology of this species that will help agencies that manage sage-grouse and their habitat.
College and Department
Life Sciences; Plant and Wildlife Sciences
BYU ScholarsArchive Citation
Retherford, Drew W., "Movements and Space-Use of Female Greater Sage-Grouse (Centrocercus urophasianus) During Nesting and Breeding Seasons" (2020). Theses and Dissertations. 9305.
sage-grouse, nesting, habitat, nest fidelity, lek, habitat, breeding movements