Give a Hoot

Giving a Hoot

By Ricketts Conservation Foundation Team

Several species of owls breed near or migrate through the Upper Hoback River Valley. Most hunt small rodents that they capture using their keen vision and hearing. Each fall, two of the smaller species, Northern Saw-whet Owl and Boreal Owl (Figure 1), migrate to lower elevations to avoid the deep snow that provides a protective blanket under which mice, gophers, and voles thrive in the resulting subnivean layer during our long winters (link to next blogpost). We can capture these owl species during fall migration by placing mist nets around a loudspeaker and playing male owl territorial calls on it (Figure 2). In 2021, Ricketts Conservation Foundation biologists decided to find out if Northern Saw-whet Owls migrated past the ranch in fall. Sixty-three birds later, we had our answer. Since then, we’ve continued our efforts and captured 773 Northern Saw-whet Owls through the end of 2024 (Figure 3). This past fall, we opened a second banding site for Boreal Owls and captured 68 individuals. This was probably the highest number of Boreal Owls captured at a single banding site in the lower 48 states.

Our reason for conducting this work is better to understand the movement patterns of these two species. Organized banding of Northern Saw-whet owls has been done in eastern and central North America for over thirty years, and we follow a capture protocol established by Project Owlnet. We also have state and federal permits to conduct this work. Before we started our banding effort, there was no sense of how many owls migrated across western Wyoming. We now know that significant numbers of birds move past us every fall. The question is to find out where they’ve come from and where they’re going.

To answer the first question, we’ve collected feathers from captured birds and sent them to Colorado State University. We’re partnering with other banding sites to provide the Bird Genoscape Project with samples that can be used to identify different populations of owls and determine where they breed. This has significant conservation implications as we can then identify populations that may face challenges to their survival.

It’s harder to find out where they’re going. Back East, there are multiple banding stations, so it’s common to capture birds banded at other sites and thereby gain an understanding of regional movements. We don’t have this opportunity because there are few owl banding stations in the Intermountain West. Instead, beginning in fall 2025, we plan to place transmitters on up to 15 birds that will provide us with GPS locations for up to two years. We can follow both owl species to their wintering and breeding grounds if successful. Stay tuned!