We began WPBO’s 17th summer owl banding season on July 1. The main focus of the summer season is juvenile Northern Saw-whet Owls (NSWO). Before we began this research in 2006, it was believed that juvenile NSWO effectively remained around their natal territories until the fall migration period. WPBO remains the only site where significant numbers of juvenile plumage NSWO have been documented between the time they fledge and head south in the fall.

Saw-whets are on a 4- to 5-year breeding cycle. This means that, effectively, their breeding success peaks and crashes every four to five years. This cycle results from fluctuations in the numbers of their prey base, mostly deer and white-footed mice. When their prey populations peak, they can naturally provide more food to their nestlings and fledge more young. When the prey populations crash, so does their breeding success. This natural breeding cycle has an extreme effect on the summer research results from year to year. Peak years have generally produced 400–600 juveniles. Crashes in reproductive success have resulted in as few as 50–60 juveniles being banded in a given summer. The first few times through the breeding cycle, we saw a very neat pattern of peaks every fifth year, with those peaks being followed immediately by the crash the following summer. The last time through the cycle, the peak occurred two years earlier than expected. That unexpected peak was in 2020; there was no crash in 2021 or 2022.

We are at a loss for what to expect this season but are due for a crash. The first four nights have been relatively slow, with 18 owls banded. Just one of those has been a juvenile NSWO, but except for two of the previous peak years, juvenile numbers have been very low at the start of the season. In two of the previous crash years, the first juvenile didn’t show up until two weeks into the season, so the fact that the first one has already arrived may be a positive sign.

An adult Northern Saw-whet Owl. Photo by Chris Neri

Season Totals of Banded Owls
Northern Saw-whet Owls: 17 (16 adult and 1 juvenile)
Long-eared Owls: 1

~ Chris Neri & Jess Consentino
2023 Summer Owl Banders

You can read the owl banders’ weekly blog posts and follow WPBO’s social media (Facebook, Instagram, and Twitter) for owl banding highlights this season.

Owl Banding Presentations — Visitors may observe owls that have been banded on Friday and Saturday evenings from dusk until midnight. Please note that banding is weather dependent and it is at the banders’ discretion to cancel banding accordingly. Observation will be limited to outdoors only. For the safety of the owls, flash photography and recording video is prohibited.