Behaviour and nesting ecology of Appalachian Ruffed Grouse (<em>Bonasa umbellus</em>)

Abstract

The substantial decline of Ruffed Grouse (Bonasa umbellus) in the southern Appalachian Mountains has been attributed in part to poor recruitment with possible links to nesting ecology. However, despite extensive research, the incubation ecology of Ruffed Grouse remains poorly understood. During 1999–2001 in West Virginia, we used videography of nesting female Ruffed Grouse to (1) quantify incubation constancy (minutes on the nest/minutes recorded) and nest survival during incubation, (2) determine whether incubation constancy predicts hatch success (proportion of eggs hatched per clutch), (3) determine the effect of the onset of laying on incubation constancy and hatch success, and (4) quantify nest visitors and depredation. Females spent about 96% of the recorded time incubating their clutches. Average incubation time per day increased by 1 h between day 1 and day 24 of incubation. Females generally left their nests twice daily, once in the morning between 0700 and 1000 for 31.7 ± 2.4 minutes (standard error) and again in the evening between 1600 and 1800 for 33.6 ± 1.5 minutes. Daily survival of nests (99.3 ± 0.4%) and nest survival for the incubation period (84.9 ± 9.3%) were high. Hatch success (the proportion of eggs that hatched among nests where at least one hatched) was high: 94.9 ± 0.02%. We found no relation between incubation constancy and hatch success. We recorded American Black Bear (Ursus americanus), Raccoon (Procyon lotor), and Long-tailed Weasel (Mustela frenata) as nest predators.