Ruffed Grouse Drumming Site Counts

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Abstract
Spring counts of drumming sites of [male] ruffed grouse, Bonassa um-bettus, were made on a 760-acre study area from 1941 to 1946, incl. The sites were located by stalking and consistent usage thereof was determined by presence of droppings and feathers. Of 55 sites, 30 were stone walls, 8 boulders or rock out-crops, 7 logs, 3 logs and stone walls, 2 stumps, and 5 undetd. The spring breeding populations were obtained for 1941, 1944, 1945, and 1946, by multiplying the number of drumming sites by 2, assuming a 1:1 sex ratio, and the breeding potentials for the same yrs. were derived by multiplying 1/2 the spring breeding population by 11, assuming 11 eggs per clutch and that all 9 9 nested. Some of the sites were used for 6 consecutive yrs. and usually the identical spots on the sites were occupied by the birds. In such cases it was thought that the same individual occupied the site each yr. Hence of 25 sites recorded in 1946, 9 had been used in 1941 and the birds were considered at least 6-yrs. old, 3 were first recorded in 1944 and were at least 3 yrs. old, 5 first recorded in 1945 were 2 yrs. old, and 8 were 1 yr. old being first recorded in 1946. The number of new sites found each year multiplied by 2 (assuming a 1:1 sex ratio) gave the number of birds surviving from the previous yr.''s breeding potential. This survival was 6.1% of the 1944 breeding potential of 198, and 3.8% of the 1945 breeding potential of 209. The spring populations detd. from the drumming site counts compared favorably with spring populations detd. by the King census method, except for 1946 The technique of obtaining a grouse drumming site count was time-consuming, and numerous assumptions had to be made to fully utilize the data.

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