Effects of forest characteristics on ruffed grouse nesting ecology in central Maine, USA.

25 November 2019

Mangelinckx, Joelle; Brown, Samantha; Allen, R.; Sullivan, Kelsey; Blomberg, Erik

Effective wildlife management requires a broad understanding of how habitat structure and composition influence habitat use and vital rates during all aspects of species’ life-cycles, however habitat characteristics may have variable importance during different life phases. The ruffed grouse (Bonasa umbellus) is a popular game bird that has long been a focal species for management, however, a greater understanding of the links between forest characteristics and components of ruffed grouse reproduction would enhance managers’ ability to promote the species. We monitored 45 nests belonging to 37 females during 2015–2017 in central Maine, USA, and evaluated the influence of forest characteristics on nest-site selection, nest survival, and female survival while nesting. Ruffed grouse females selected nest sites with 36% greater horizontal visual obstruction than found at other sites that were locally available to them, but we found no evidence that this selected habitat characteristic influenced survival. Cumulative nest success was 42.8% and reduced daily nest survival was associated with the presence of coarse woody debris (CWD) at nest sites. However, female survival while nesting was reduced with the presence of CWD, greater tree basal area, and greater conifer stem density at nest sites; females had a 74.4% chance of survival during the length of time required to successfully nest. When nests where the incubating female was killed were censored from the nest survival analysis, no habitat characteristics influenced the probability of other sources of nesting failure (i.e. predation or abandonment). Our results suggest that forest structure and composition affect the probability of ruffed grouse nesting success through their influence on the ability of females to survive nesting. We provide management suggestions to promote attractive ruffed grouse nesting habitat while potentially mitigating female mortality while nesting.