Natality of ruffed grouse Bonasa umbellus in central Wisconsin, USA

Abstract

Radio‐marked female ruffed grouse Bonasa umbellus were monitored in central Wisconsin, USA, during 1983–1988 to estimate nesting rates (the percentage of hens that initiate a clutch), clutch size, nest success, and the prevalence and success of renests. All 23 radio‐marked females initiated a clutch, 22 completed a first clutch; the remaining hen was killed by a predator during laying. Mean clutch size of first nests was 11.0 ± 0.5 eggs (range = 7–13). Five of nine (56%) hens attempted to renest with a mean clutch size of 7.4 ± 1.3 eggs (range = 6–9). Mean nest success was 46%; 43% for yearlings and 60% for adults. First nests produced the large majority of eggs that hatched (86.1%) compared to renests (13.9%). Productivity was estimated at 5.8 chicks hatched for each hen alive on 20 April, the mean date of the first egg laid.

Survival and Habitat of Ruffed Grouse Nests in Northern Michigan

“…The differences between the results for clutch size from this study and others may be due to the lack of, or imprecise, classification of first and second nests during earlier studies. Clutch size for known first nests in Wisconsin (11.0), however, also was less than in our study, whereas clutch sizes of known second nests were similar (7.4 versus 7.3 in our study; Small et al 1996).…”

“…Two females in our study renested after incubating their first nest for 1-2 weeks, and five renesting hens in Wisconsin incubated first nests for 5-18 days (Small et al 1996). Stage of the nesting sequence, therefore, may not be as important to the probability of renesting as previously thought (Bump et al 1947:291).…”

“…Received 16 July 2002, accepted 22 February 2003 Although the importance of nest success to understanding grouse population fluctuations has been recognized (Gullion 1970), it remains little studied. Brander (1967), Barrett (1970), and Maxson (1974Maxson ( , 1978a studied the behavior of female grouse during the breeding season, and information about hatching dates and clutch size has come from many sources (Hale and Wendt 1951, Cringan 1970, Rusch and Keith 1971, Porath and Vohs 1972, Kubisiak 1978, Maxson 1978b, Small et al 1996. A full understanding of grouse chick production, however, is lacking because little information is available for nest survival rates, renesting attempts, and nesting habitat.…”

“…Survival rates of Ruffed Grouse (Bonasa umbellus) nests, some based on large samples (Bump et al 1947), have been reported only as the percentage of observed nests that hatched chicks (Rusch and Keith 1971, Maxson 1978b, Small et al 1996 (Mayfield 1961, Johnson 1994. The degree of bias may not be constant among studies, so comparing apparent survival rates among different areas or time periods may not be appropriate.…”

“…The second nesting attempt of a marked female grouse after failure of the first nest was first documented by Barrett (1970). The only additional data for known second nests were reported by Small et al (1996). The assumption of renesting often is based on evidence of a secondary peak in hatching that usually involves notably smaller clutches (Cringan 1970, Porath and Vohs 1972, Maxson 1978b.…”