We used 13 years of historical data to investigate effects of coyote (
Canis latrans) removal on depredation of domestic sheep. The 2,168-ha
study area maintained >1,000 breeding ewes that produced lambs yearly.
Records from 1981 through 1994, which included numbers of sheep, numb
ers of sheep known killed by coyotes, known numbers of coyotes removed
, and annual numbers of trapper hours were summarized and analyzed on
a yearly, seasonal, and monthly basis. We used regression analysis and
found that annual, seasonal, or monthly depredation losses were not c
orrelated with number of coyotes removed. Both annual number of lambs
killed and number of coyotes removed were positively correlated with n
umber of trapper hours. We used a cross-correlation analysis to detect
any relation between coyote removal and subsequent depredation losses
at all monthly intervals from 0 to 24 months. We found a trend of low
negative correlation between depredation losses and number of coyotes
removed for lags of 2-12 months, suggesting some reduction of sheep k
illing due to control efforts. Low correlations within years may be du
e to inconsistent removal of depredating coyotes while removing primar
ily young, nondepredating coyotes. Lack of correlation between years m
ay have occurred because past control efforts have not had a lasting r
eduction on coyote density due to immigration, the compensatory nature
of control efforts on coyote mortality, reproductive compensation in
the resident coyote population, or all 3 factors.