2026 Owl Banding Season

RCF Owl Banding Tent at Jackson Fork Ranch

Fall in western Wyoming brings vibrant yellow hues, crisp nights, and shorter days. For many birds, these seasonal changes also signal that it is time to move. While it’s easy to notice the increasing numbers of warblers and sparrows making their way south, owl migration is largely invisible to us. On quiet September nights, these birds move across the landscape when most people are asleep. To better understand how owls use the southern Yellowstone Ecosystem during fall migration, RCF biologists monitor forest owl movements from early September to mid-November.

RCF’s fall owl monitoring program targets three species: Northern Saw-whet Owls (Aegolius acadicus), Boreal Owls (Aegolius funereus), and Long-eared Owls (Asio otus) (Figure 1). All three species use forested habitats and can be particularly difficult to study outside of the migration period. Northern Saw-whet Owl migration is relatively well studied in eastern North America, where a large network of owl-banding stations has operated for decades. By sharing capture and recapture information, these stations have helped researchers identify migration timing and movement patterns across that region. In the Intermountain West however, banding stations are much more widely separated, and owl movements remain comparatively poorly understood.

Each owl species moves through the region at different times. We typically encounter Long-eared Owls in September, with captures tapering off in October. Northern Saw-whet Owl numbers increase through September before declining later in the fall. Boreal Owls generally appear later in the season and are the least predictable. Unlike more regular migrants, Boreal Owls can exhibit irregular or nomadic movements that vary considerably between years, leaving much about their movement patterns in North America unknown.

Fall migration provides RCF biologists with a unique opportunity to study these otherwise elusive birds. Migrating owls can be attracted to net arrays using audio playbacks that broadcast the calls of each target species (Click on link below to hear a Northern Saw-Whet Owl calling). RCF biologists operate these stations for six hours each night, beginning shortly after sunset. Nets are checked regularly, with captured owls removed carefully and brought to the banding station for processing.

https://www.allaboutbirds.org/guide/Northern_Saw-whet_Owl/sounds

Each captured owl receives a uniquely numbered U.S. Geological Survey band and is weighed and measured before being released. Biologists measure wing chord and body mass, while plumage characteristics (Figure 2) and molt patterns (Figure 3) are used to determine sex and age, when possible. These data allow RCF to record the age and sex composition of migrating owls and see how migration timing varies among species and years. The band also allows an individual to be identified if it is captured again. An owl banded by RCF and later encountered at another station, or a previously banded owl captured by RCF, provides a direct connection between two locations. These encounters are particularly valuable for understanding owl migration, because their nocturnal movements are difficult to observe directly. Over time, banding and recapture data from stations across North America can help identify migration routes and provide a better understanding of how owls move through the landscape.

Figure 2: Hatch Year (HY) Northern Saw-whet Owl: New feathers contain a chemical compound known as " Porphyrin" that glows neon pink under a black light. Young birds have all new feathers, so this bird can safely be aged as an HY.

On particularly busy nights, RCF biologists may capture more than 25 Northern Saw-whet Owls, by far the most abundant owl encountered during our fall banding efforts. Catching a single Long-eared or Boreal Owl, however, can be just as exciting. Both are encountered less frequently at our stations, making every capture an important addition to what we know about their movements through western Wyoming.

Understanding how these owls use the Yellowstone Ecosystem during fall is one of the major questions RCF hopes to address through long-term monitoring. By operating banding stations consistently across multiple years, we can establish baseline information about the number, timing, age, and sex of owls moving through the southern Yellowstone Ecosystem. These data can then contribute to the large network of owl migration research across North America and help fill an important geographic gap in our understanding of western owl movements.

Over the course of RCF’s fall banding efforts, biologists have captured 1,237 owls since 2021. As of September 24, 2026, another 142 owls have been captured this season. Each bird provides another small piece of a much larger puzzle—and continues to help us better understand how these secretive forest owls move through western Wyoming.

2025 Fall Bird Banding Summary

American Redstart- This juvenile was the first of its species documented in the Hoback Basin

Ricketts Conservation Foundation’s 2025 fall bird banding season began on August 25th at our songbird migration station. Unlike over the summer when we catch songbirds using ten nets at nine rotating locations, our fall station is comprised of fifteen nets that are run every day at the same location. In autumn, disturbing nesting birds is no longer a concern, and instead our aim is to discover how migrating birds are using a select patch of stop-over habitat. For our fall banding efforts, a location on Jackson Fork Ranch along the Hoback River is utilized. This patch is comprised of riparian habitat with Willows and Cottonwood trees as well as tall Spruces and some Pines. The diverse flora and fresh water at this spot make it an appealing location for migrating birds to stop to rest and refuel along their journey south for the winter.

Fall songbird migration in western Wyoming is a fairly short phenomenon, with the bulk of the small migratory bird species moving through the region during the month of September. Due to some bad weather in late September and early October, our final morning of songbird banding was September 27th. Despite ending a few days earlier than we otherwise would have, it was an excellent season. The songbird crew banded 739 new birds and had 74 unique recaptures, comprised of 44 different species (Figure 1). Our 2025 total of 813 captures was a new record high, up from 694 in 2024 and 515 in 2023. Our most abundant bird caught in fall continues to be Wilson’s Warbler (113), but we also had a significant increase of Dark-eyed Juncos. In 2025 we banded 109 Juncos, compared to only 16 in 2024. Our 2025 fall season also had a few exciting first-time species captured- American Redstart, Clay-colored Sparrow, and Townsend’s Warbler are all uncommon migrants in western Wyoming. The Redstart and Sparrow species had not been previously documented in the Hoback basin, and this was only the 3rd fall record of Townsend’s Warbler in the area. These species are not known to regularly breed in our region and the individuals we caught this fall were likely migrating from breeding grounds in Montana, Idaho, or Canada to wintering grounds in Mexico.

On the evening of September 1st, we began our target banding effort for Northern Saw-whet Owls. Saw-whets are a small species of migratory owl that RCF biologists began to study in 2021. Since 2023, we have been conducting songbird banding in the mornings and Saw-whet Owl banding at night at the same location on Jackson Fork Ranch. Several miles up the river from the songbird and Saw-whet Owl banding station, we established a second Owl banding site in 2024, specifically to catch Boreal Owls. Boreal Owls are larger than Saw-whets but still very small compared to other familiar owl species like Great-horned Owl. Boreal Owls are considered a nomadic species but are under-studied in North America. Through our banding efforts, we hope to better understand their winter movements and juvenile dispersal. Both Boreal and Saw-whet Owls breed in high elevation forests of the Yellowstone Ecosystem, and are well insulated for cold weather with lots of body feathers, particularly the Boreals. While most Saw-whets migrate out of the area by the end of October, many Boreals are likely to spend all winter in the region.

Our 2025 Northern Saw-whet Owl season ran until October 31st, and over the 2-month capture period we banded 213 new Saw-whets. While catching over 200 of these birds is still a very good season, it was fewer owls than the past 2 years- we banded 320 in 2024 and 253 in 2023. Saw-whet Owls are known to sometimes have large year-to-year fluctuations in local population size, likely tied to small mammal populations and juvenile survival. Catching over 300 last fall was exceptional, so having our number decrease this year was not a big surprise.

Since Boreal Owls can overwinter in our area and have unpredictable nomadic movements, we continue to try catching them into November. This year our final night of Boreal Owl banding was November 22nd. In slightly over 2 months of effort we banded 23 Boreals Owls. This was a big drop off from last year’s total of 68. Boreal Owl populations likely experience yearly fluctuations similar to the Saw-whet Owls, but we are still learning about their population size and seasonal occurrence in our area. Given the overall perceived scarcity of Boreals, catching 23 this year was still very valuable, and we hope to continue to gain a better understanding of their population with on-going fall banding efforts.

2025 was another successful year for RCF’s fall migration banding operation and it would not have been possible without all the hard work of our seasonal banding crew- Noah Price, Olivia Fortuna, Wyatt Westerkamp, and Aiden Gifford. Without their passion and dedication, this banding season would not have been possible! Below is a chart of all our captures from this past fall. With the continued support of Ricketts Conservation Foundation and Jackson Fork Ranch, we look forward to continuing to use bird banding to study migratory songbirds and owls in the Hoback Basin.

Figure 1. Capture results summary for 2025 fall migration bird banding.

Give a Hoot

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!