Variation in habitat selection by male Strix nebulosa (Great Gray Owls) across the diel cycle

Abstract

Despite the long-standing recognition that animals partition activities, for example, across different periods of the day, understanding of how habitat selection varies according to specific temporal periods or behavioral activities remains limited for most species. For example, although much of the animal kingdom is nocturnally active, studies that characterize nocturnal behavior remain relatively rare, which precludes a thorough understanding of key habitats. We used Global Positioning System tracking and remotely-sensed environmental data to evaluate whether breeding-season habitat selection by adult male Strix nebulosa (Great Gray Owls) ( n = 19) varied across diel periods (dawn, day, dusk, and night). We focused on male owls because their habitat selection remains largely unknown despite the critical role they play as food provisioners. To address knowledge gaps related to nocturnal habitat, we also evaluated finer-scale, microhabitat selection by male owls at night. Owls were more active during dusk through dawn, suggesting that owls forage during crepuscular and nighttime periods and roost during the day. Owls avoided herbaceous wetlands during the day but strongly selected them at dawn, dusk, and night, indicating time-dependent habitat selection. Moreover, owls avoided dry meadows at all times of the day, suggesting that wet rather than xeric meadows are important for foraging. Owls also selected nighttime microhabitats that facilitated foraging, such as those with the presence of primary prey and open understories. During the daytime, owls chose areas with closed canopies and increased soil moisture, which likely provided suitable roosting habitat. Owls avoided development but selected areas closer to roads, particularly containing preferred habitats. Understanding of habitat selection across activity periods, temporal windows, and other contexts can improve the conservation of critical habitat for wildlife. Our work contributes to understanding of how animals balance resources related to food provisioning versus safety, both of which are critical for individual fitness and population persistence.