SURVIVAL AND HABITAT OF RUFFED GROUSE NESTS IN NORTHERN MICHIGAN

Abstract

Abstract Effective management of Ruffed Grouse (Bonasa umbellus) populations requires a full understanding of chick production. Previous reports of nest survival for Ruffed Grouse are biased because they did not account for successful nests being more likely to be found, and the role of habitat quality in determining nest survival is unknown. We determined survival rates of Ruffed Grouse nests in northern lower Michigan using the less biased Mayfield estimator, defined differences between first and second nests, and compared the local habitat characteristics of successful and unsuccessful nests. Median hatching dates were 10 June for first nests (n = 34) and 1 July for second nests (n = 6). First nests had a lower survival rate (0.442, 95% CI = 0.270–0.716), a higher mean clutch size (12.7 eggs ± 0.3 SE), and higher egg hatching rate (0.960, 95% CI = 0.900–0.997) than did second nests (nest survival = 0.788, 95% CI = 0.491–1.00; clutch size = 7.3 eggs ± 0.3 SE; and hatching rate = 0.826, 95% CI = 0.718–0....