US Geological Survey


Date of this Version



The Journal of Wildlife Management, Vol. 46, No. 3 (Jul., 1982), pp. 686-693.


U.S. government work.


Gray wolves (Canis lupus) were studied from April 1972 through April 1974 in National Forest in northeastern Minnesota by radio-tracking and simulated howling. Based during 217 of 456 howling sessions, the following recommendations were derived for using howling as a census technique: (1) the best times of day are dusk and night; (2) July, August, and are the best months; (3) precipitation and winds greater than 12 km/hour should be avoided; (of 5 single howls should be used, alternating "flat" and "breaking" howls; (5) trials should 3 times at about 2-minute intervals with the first trial at lower volume; and (6) the trial series repeated on 3 nights as close to each other as possible. Two censuses are described: a saturation and a sampling census.