eWestern Birds
The Quarterly Journal of Western Field Ornithologists
Occupancy of Habitats by Mexican Spotted Owls in Relation to Explosive Noise and Recreational Access at Los Alamos National Laboratory
Charles D. Hathcock, Leslie A. Hansen, and David C. Keller
ABSTRACT: We examined 15 years of presence/absence data on the Mexican Spotted Owl (Strix occidentalis lucida) at Los Alamos National Laboratory in seven areas managed as Spotted Owl habitat and affected by two types of anthropogenic disturbances: human recreation and relatively frequent but brief impulse noises caused by explosives. On the basis of the percent of years each area was occupied (the occupancy rate), the type of disturbance had an apparent effect on habitat occupancy. The rate of occupancy of Spotted Owl habitat within 2.4 km of firing sites with restricted access was 31% while in habitat >2.4 km from firing sites in which recreational access was allowed it was 7%. These results suggest that the Spotted Owl’s use of habitat at Los Alamos is not adversely affected by noise generated during explosives tests but may be adversely affected by recreational access.