Male greater sage‐grouse movements among leks

Abstract

Movements among leks by breeding birds (i.e., interlek movements) could affect the population's genetic flow, complicate use of lek counts as a population index, and indicate a change in breeding behavior following a disturbance. We used a Bayesian multi‐state mark‐recapture model to assess the daily probability of male greater sage‐grouse (Centrocercus urophasianus) interlek movements and estimate factors influencing movements among leks. We fitted 145 males with solar Argos global positioning systems platform transmitter terminals over 4 years (2011–2014) in Carbon County, Wyoming, USA. The daily probability of a male sage‐grouse moving among leks ranged 0.003 (95% CI = 0.000–0.010) in 2011 to 0.010 (95% CI = 0.001–0.021) in 2013, indicating high daily lek fidelity throughout the season, although there was a 5–42% chance annually a male would move at least once to another lek throughout the season (x¯ days analyzed/M = 55 ± 3.3 days [SE]). Interlek movement probabilities were strongly affected by day of year, peaking early in the lek season. Interlek movements were positively associated with elevation. Seasonal interlek movements occurred more frequently than previously reported, and can bias lek counts in early spring as males move from low to high elevation leks, which reinforces interlek movements as a critical component of lek ecology. © 2016 The Wildlife Society.

Dual‐frame lek surveys for estimating greater sage‐grouse populations

“…We surveyed during the peak period of male lek attendance to minimize the influence of changes in within‐year availability and detectability, and we minimized the duration of the survey period (18 days) to reduce the potential for inter‐lek movement that might induce dependence in counts among leks. Variable lek attendance during the survey period (Blomberg et al ) or inter‐lek movement of males (Fremgen et al ) that causes some leks to be abandoned or occupied between survey occasions may violate the first assumption. In such cases, estimates of occupancy would be more appropriately interpreted as the probability of leks being used by males and estimates of detection probability as the combined probability of male presence on a lek and detection given presence (Kendall et al ).…”

“…However, this limitation creates challenges for establishing effective policies to manage and conserve populations at local scales, or in response to immediate concerns. Therefore, investigating the reliability of lek‐count data for monitoring changes in greater sage‐grouse populations, testing their underlying assumptions, and developing innovative methods to estimate population size are research priorities (Naugle and Walker ) and the focus of several recent studies (Baumgardt , Blomberg et al , McCaffery et al , Baumgardt et al , Fremgen et al ).…”

The potential importance of unburned islands as refugia for the persistence of wildlife species in fire‐prone ecosystems

“…These factors may enhance the successful breeding of sage‐grouse at leks in unburned islands. Although movement between leks is uncommon (e.g., Fremgen et al, ; Gibson, Blomberg, Atamian, & Sedinger, ), male sage‐grouse may experience lower lek fidelity in disturbed and fragmented landscapes as compared to intact habitats (Foster et al, ; Schroeder & Robb, ). As a result, the apparent high persistence within unburned islands may also be partly caused by postfire movements of male sage‐grouse from burned leks to unburned island leks.…”

“…Besides cheatgrass cover at an intermediate scale, the strongest predictor was vegetation height of sagebrush at the fine spatial scale. This may be attributed to sage‐grouse preferentially nesting under sagebrush (Fremgen et al, ; Walker et al, ), where the most successful nests are placed under tall sagebrush with high foliar cover (Holloran et al, ). Because vegetation height was strongly correlated with unburned area at the local scale, this effect may also be attributed to the general presence of intact remnant sagebrush habitat in the direct vicinity around leks.…”

“…Data were obtained from the Oregon Department of Fish and Wildlife (ODFW) which monitors sage‐grouse populations in Oregon. Leks typically occur in the same locations each year (Connelly, Hagen, & Schroeder, ), and male sage‐grouse rarely move away between leks during the breeding season (Fremgen et al, ). When leks were situated within a lek complex (a group of multiple leks situated in close proximity), leks were counted on the same day to minimize potential movement of males between leks within the same lek complex.…”