Northern Saw-whet Owl Monitoring Program
Categories: Research; Advocacy
Written by Olivia Maillet; Photographs by Patricia Homonylo
At one time, it was believed that Northern Saw-whet Owls were one of the most rare owls in North America. Despite migrating through much of North America, due to their small size and cryptic behaviour, they went largely unnoticed. After over a century of theories, observations, and preliminary banding efforts, interest in understanding the lives of Northern Saw-whet Owls became undeniable. In 1986, researchers decided to try using a tape-recording of a male Northern Saw-whet Owl’s “toot” call to lure owls into the nets. This advancement in research methods resulted in more than 10x increase in captures versus passive netting. In 1994, increased interest in their migration and advancement in capture methods led to a large, collaborative network of researchers across North America: Project Owlnet. Through this international effort, hundreds of groups of researchers use standard methods to seek to understand the migration and population dynamics of Northern Saw-whet Owls.
Owl bander, Ketha, checking the nets.
Owl research at PEPtBO
Since 2001, Prince Edward Point Bird Observatory has been operating a standardized Northern Saw-whet Owl monitoring program. During fall migration, we target and catch Northern Saw-whet Owls in specialized mistnets as they move further south for the winter. Despite their small size, Northern Saw-whet Owls are larger than the average songbird we catch (think warblers or sparrows!). Therefore, we have to use a larger net mesh size which keeps them in the pockets before trained staff and volunteers retrieve them from the nets at regular intervals. Like songbirds, we put owls in (slightly larger) soft cloth bags to keep them safe and calm before they are banded.
Once back at the lab, each owl we catch receives a metal leg band engraved with a unique number. We determine the age of each owl by looking at the quality of different groups of feathers on their wings. Due to compounds called porphyrins, the flight feathers of Northern Saw-whet Owls fluoresce hot pink under UV light. On young birds, all of their flight feathers will fluoresce or glow evenly pink, because they were all grown in at the same time in order to leave the nest. On older birds, new, replaced feathers will glow pink, and older, more worn feathers, will have reduced flourescence. This difference in fluorescence allows us to demonstrate clear diffferences in feather ages.
We then measure its wing and weight, which help us to determine whether the owl is male or female. Once the owl has received its new band, and we have collected all necessary data, we release it back into the night to continue its southbound migration.
Recaptures
Due to the use of audio lures, Northern Saw-whet Owls have a relatively high recapture rate. In future years, owls are often recaptured by us and by other stations using the same research methods. When we catch an owl that is already banded, we record its unique band number, which is attached to all of its original banding data: where and when it was banded, its age at the time, its sex, and all of its measurements. Recaptures can be from the same night, the same season, or across years.
Owls banded at PEPtBO have been recaptured in many places, such as New York, Nova Scotia, Minnesota. As well, other owls banded elsewhere, such as Quebec, Indiana, and Virginia have been recaptured at PEPtBO. Connecting the dots through recapture locations across hundreds or thousands of kilometers can show us the migration patterns of individual owls and populations as a whole.
Our impact
Through banding, we learn about their migration pathways and timing, and can monitor trends in populations across North America. PEPtBO’s Northern Saw-whet Owl monitoring data has been included in various reports and publications contributing to owl research and conservation. Public and private owl banding nights not only provide funding for us to continue this research program, but also inspire a passion for conservation in attendees who have the chance of seeing these incredible, tiny predators up close.
How you can help
Help promote owl research and conservation:
Donate to owl research. Your donations help advance and sustain our monitoring programs for years to come.
Don’t use rodenticides. Owls eat rodents. Using rodenticide puts owls and other wildlife at risk. Try alternatives to rodenticides to keep owls safe.
Make windows bird-safe. Like songbirds, owls are susceptible to mortality from window strikes. Learn more about the variety of options to make your windows safe for all birds.
Get involved
For the chance to learn more about owl research and for the possibility of seeing these pint-sized owls up close, follow our social media channels and subscribe to our newsletter to make sure you don’t miss out on our public owl banding nights in October.