MOUNTAIN PLOVER POPULATION RESPONSES TO BLACK-TAILED PRAIRIE DOGS IN MONTANA

Abstract

Abstract We studied a local population of mountain plovers (Charadrius montanus) in southern Phillips County, Montana, USA, from 1995 to 2000 to estimate annual rates of recruitment rate (f) and population change (λ). We used Pradel models, and we modeled λ as a constant across years, as a linear time trend, as year-specific, and with an additive effect of area occupied by prairie dogs (Cynomys ludovicianus). We modeled recruitment rate (f) as a function of area occupied by prairie dogs with the remaining model structure identical to the best model used to estimate λ. Our results indicated a strong negative effect of area occupied by prairie dogs on both λ (slope coefficient on a log scale was −0.11; 95% CI was −0.17, −0.05) and f (slope coefficient on a logit scale was −0.23; 95% CI was −0.36, −0.10). We also found good evidence for a negative time trend on λ; this model had substantial weight (wi = 0.31), and the slope coefficient on the linear trend on a log scale was −0.10 (95% CI was −0.15, −0.05). Y...