Lasers as nonlethal avian repellents

Lasers have been demonstrated to be potentially effective avian repellents; however, studies combining adequate controls and replication that test such applications of lasers in wildlife management have not been reported. We conducted 2-choice cage tests to quantify the effectiveness of a 10-mW, continuous-wave, 633-nm laser as a visual repellent (treating a perch) against brown-headed cowbirds (Molothrus ater) and European starlings (Sturnus vulgaris), and a 68-mW, continuous-wave, 650-nm laser in dispersing (i.e., targeting birds with the laser) starlings and rock doves (Columba livia) from perches and Canada geese (Branta canadensis) and mallards (Anas platyrhynchos) from grass plots. All experiments were conducted under low ambient light (less than or equal to3 1x) conditions. In 3 experiments with stationary and moving laser beams treating a randomly selected perch, brown-headed cowbirds were not repelled. Similarly, a moving beam did not repel European starlings from treated perches or cause them to disperse when targeted. Rock doves exhibited avoidance behavior only during the first 5 min of 6 80-min dispersal periods. Notably, 6 groups of geese (4 birds/group) exhibited marked avoidance of the beam during 20-min periods (n = 23), with a mean 96% of birds dispersed from laser-treated plots. Six groups of mallards (6 birds/group) also were dispersed ((x) over bar = 57%) from treated plots during 20-min periods (n = 12), but habituated to the beam after approximately 20 min. We contend that lasers will prove useful as avian repellents, but further controlled studies are needed to evaluate species-specific responses relative to laser power, beam type, wavelength, light conditions, and captive versus field scenarios.