Enhancing detection of short‐eared owls in Québec: Habitat quality, seasonal occurrence, and avian proxies

Abstract

The short‐eared owl ( Asio flammeus ) is one of the most widely distributed owl species in the world. However, several indicators suggest a decline in its population globally. In Canada, the Committee on the Status of Endangered Wildlife in Canada recently suggested the species be listed as threatened. Despite concerted efforts to gain a deeper understanding of the factors contributing to the decline in short‐eared owl populations, there remains a significant dearth of information, particularly concerning its nesting environment. Using data from the Endangered Bird Monitoring Program from 1994 to 2019, we developed a breeding‐season habitat quality model to identify the most suitable nesting areas in southern Québec, Canada. We also examined site fidelity at the species level by quantifying the proportion of sites repeatedly occupied across breeding seasons. We further evaluated whether presence during the non‐breeding period predicted subsequent breeding‐season presence, which could improve detection of short‐eared owl during surveys. Finally, we tested for a correlation with several other bird species to act as reliable proxies of short‐eared owl presence using freely available citizen‐science data. Three covariates (altitude above sea level, proportion agriculture, proportion forest) best explained the probability of the species’ occurrence. We observed low site fidelity, with only 17% of the sites being occupied in multiple years during the breeding season, and differences in short‐eared owl habitat use between non‐breeding and breeding seasons, emphasizing the importance of understanding inter‐seasonal habitat dynamics for effective conservation. Several species have been regularly observed simultaneously with short‐eared owls in high‐quality habitat such as the clay‐colored sparrow ( Spizella pallida ) and willow flycatcher ( Empidonax traillii ), but the most indicative species to act as a proxy seems to be the vesper sparrow ( Pooecetes gramineus ). This species could serve to enhance detection rates for short‐eared owls in high‐quality breeding habitats during the reproductive season.