p. 606

In 1994, an estimated $17.7 million in sheep was lost to predators in the United States, with the majority of losses attributed to coyotes. In Utah, Idaho, and Wyoming, 34% of all producer-reported sheep and lamb losses were to coyote predation, which amounted to $4.8 million in losses during 1995.

In the Intermountain West, preventive aerial hunting to protect livestock on summer pastures usually occurs from January through March, but sheep are not placed in these pastures until mid-June or July…. Immigration my negate reductions in coyote density by the time the sheep arrive on the summer allotments.

p. 607

Sheep [in the study] were cared for by a shepherd who remains with the sheep, keeps the sheep band from scattering throughout the pasture, and watches for sick or dead sheep.

p. 609

An average of 0.1 coyotes/km2 were removed from treated sites

During the treatment period, areas with aerial hunting had fewer confirmed and estimated lamb losses to coyotes. Estimated coyote losses were reduced from 2.8% to 0.9% of the lambs present in a pasture…. Aerial hunting… did not reduce the number of coyotes removed during summer predation management (SPM).

In Utah, the cost of aerial hunting was estimated at $425/hr, and the average cost to keep a WS specialist supplied and in the field for a year (1,852 hrs. of work) was approximately $50,000… we estimated that aerial hunting removed an average of 2.3 coyotes/hr at a cost of $185/ coyote, while corrective control removed 0.03 coyotes/hr at a cost of $805/ coyote.

2.1 hr ($893) of aerial hunting per area resulted in an average difference of 19.9 hr ($537) of SPM… we estimated that aerial hunting resulted in a savings of 17.5 lambs/area versus untreated areas (yields a savings of $1328/area in lamb value) $1,865 of benefits resulted from $893 in expenses yielding a 2.1:1 benefit:cost ratio.

p. 611

Although continued coyote immigration could result in precontrol coyote densities by the time sheep arrive, lamb losses would still be lower because these new coyotes arrived too late to mate, so there would still be fewer coyotes with pups in the population.

Changes in terrain, coyote density, aircraft, hunting technique, and the intensity or timing of aerial hunting may affect results.