Patterns of nest attendance by female Greater Prairie-Chickens (Tympanuchus cupido) in northcentral Kansas

Abstract

Nest attendance behavior is a critical component of avian ecology that influences nest survival and population productivity. Birds that provide uniparental care during incubation and brood-rearing must balance the benefit of reproductive success with the costs of physiological needs and predation risk. We used miniature nest cameras to record 5904 h of video footage at 33 nests of Greater Prairie-Chickens (Tympanuchus cupido) during 2010 and 2011 in northcentral Kansas. We quantified the timing and duration of incubation bouts to address alternative hypotheses about physiological requirements and predation risk as drivers of incubation behavior. We also identified nest predators and determined timing of predation events, and tested for effects of nest attendance and monitoring technique on nest survival (video vs. telemetry). Female prairie chickens exhibited high incubation constancy per day (~95 %) and typically took two ~40-min recesses per day: one after sunrise and one before sunset. Mesocarnivores were responsible for 75 % (18 of 24) of nest losses, and most nest predation events occurred during crepuscular or overnight hours. Controlled comparisons provided no evidence that video surveillance attracted predators to nests. Variation in nest attendance had a minimal effect on nest survival compared to height of vegetative cover at the nest site. Timing of recesses did not indicate avoidance of predator activity in our study system. The bimodal pattern of incubation breaks observed in most grouse species is likely driven by physiological requirements of the female rather than predation pressure. Female Greater Prairie-Chickens appear to prioritize their metabolic needs and future reproductive potential over current nest survival.