Water use and diurnal ranges of Coues white-tailed deer

I evaluated water use by female Coues white-tailed deer (Odocoileus virginianus couesi) and calculated their diurnal ranges relative to available water in southeastern Arizona during hot-dry and hot-wet summer seasons. Developed water sources were scarce in 1988 and abundant during 1989. Freestanding water was not the only determinant of diurnal seasonal ranges. Not all diurnal seasonal ranges contained permanent water, but a water source density of 1/km² was sufficient during the 1989 hot-dry season and ephemeral water was common in hot-wet seasons. Deer visited developed water sources regularly during hot-dry seasons and infrequently 14 days after the summer rains began. Large amounts of preformed water were available in hot-wet season diets, but permanent or ephemeral water was necessary to meet total water requirements. Visits of cattle to troughs did not preclude deer use because of different activity patterns between the 2 species. Wildlife managers should provide free-standing water in Coues white-tailed deer ranges during hot-dry seasons and in the early part of hot-wet seasons. If winter precipitation is substantially below normal, available free-standing water in summer is especially critical