TEMPORAL, CLIMATIC AND LUNAR FACTORS AFFECTING OWL VOCALIZATIONS OF WESTERN WYOMING

We evaluated the effect of season, time after sunset, lunar phase, clo ud cover and temperature on the vocalizations of Long-eared (Asio otus ), Boreal (Aegolius funereus) and Northern Saw-whet (A. acadicus) Owls in northwestern Wyoming. All three oa species were most vocal in Marc h and April. Boreal Owls were more vocal in the first hr after sunset while Long-eared and Northern Saw-whet Owls vocalized most during the first two hr after sunset. Northern Saw-whet Owls sang more than expec ted during half to full moons and under 50-75% cloud cover Only Northe rn Saw-whet Owls responded to temperature, singing less than expected below -5 degrees C.