The effect of industrial noise on owl occupancy in the boreal forest at multiple spatial scales

Noise in natural environments can mask important acoustic signals used for animal communication. Owls use vocal communication to attract mates and defend territories, and also rely on acoustic cues to locate their prey. Industrial noise has been shown to negatively affect owl hunting success and reduce foraging efficiency by affecting their ability to detect prey, but it is not known if this results in reduced habitat suitability for owls in areas near industrial noise sources. To determine if owls avoid areas surrounding industrial noise sources in northeastern Alberta and at what scale, we acoustically surveyed for owls at sites with chronic industrial noise, sites with intermittent traffic noise, and sites with no noise. We deployed autonomous recording units at multiple stations within each site to detect territorial individuals vocalizing. Detections of owls were extracted from the recordings using automated species recognition and analyzed using occupancy models at two spatial scales. Barred Owls (Strix varia), Great Horned Owls (Bubo virginianus), and Boreal Owls (Aegolius funereus) were equally likely to occupy both types of noisy sites compared to sites with no noise, indicating that site level occupancy (representing a home range scale) was unaffected by the presence of noise sources on the landscape. On a smaller scale, there was no decline in station level occupancy (representing use of the area surrounding recording stations) at stations with higher noise levels for either of the three owl species. Our study contributes to research on the effects of anthropogenic noise, but suggests the effect on owls is minimal, and unlikely to result in a population change.