Factors most closely explaining activity patterns and behavior of northern saw-whet owls in migratory stopover habitat

The northern saw-whet owl (Aegolius acadicus)—hereafter NSWO—is a small migratory owl whose nonbreeding ecology is poorly known. I captured and tagged 43 NSWO from 2022-2023 at Kennekuk County Park in central Illinois—a site used by NSWO as a migratory stopover and wintering location. The goal was to investigate how activity patterns (i.e., movements) in the dusk, dawn, and night were impacted by environmental covariates. Owls were most active at dusk and dawn and on warmer darker nights with light winds and no precipitation earlier in the fall season. NSWO are known to be very quiet during the nonbreeding season and little is known regarding how owls interact. I used automated radio telemetry and acoustic playbacks to determine if NSWO moved towards or away from conspecific vocalizations and recorded any vocal response from the owls. I played vocalizations to radio-tagged owls near an automated radio telemetry stations to determine if the bird moved in response to the playback. NSWO rarely vocally responded to acoustic playbacks (33.3% of the time they vocalized), although birds moved closer to the source of the vocalization. The activity patterns of NSWO appear to parallel those of their rodent prey and it is likely that the covariates that are impacting their activity are also impacting the activity patterns of their prey. While NSWO are not very vocal on the nonbreeding grounds they do appear to respond to conspecific playback by approaching. There is much more to learn about the ecology and behavior of NSWO and research on the behavior of their primary prey (small rodents) and primary threat (barred owls, Strix varia) will likely further our understanding of their movements and vocalizations.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Avara, Michael R

Contributors dc:contributor

• Ward, Michael P
• O'Keefe, Joy M
• Benson, Thomas J

• saw-whet owl, migration, activity patterns, stopover behavior

Statement dc:rights

• Copyright 2025 Michael Avara

Language dc:language

en

Handle dc:identifier

https://hdl.handle.net/2142/129655

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/129655