By: Aaron Coolman, Motus Technical Coordinator and Avian Ecologist
From June 20 – June 26, I traveled to Nova Scotia, Canada, in collaboration with long-time owl bander Randy Lauff of St. Francis-Xavier University, located in the town of Antigonish. Leaving Chester County, I set off with the goal of capturing and tagging Northern Saw-whet Owls breeding in the boreal forest with Motus transmitters in an effort to track regional migration of this secretive species. Not far from the campus is Archibald Lake, a recently protected freshwater lake thanks to the hard work of local land trusts, conservationists, and politicians. This lake has been designated a Provincial Wilderness Area, and rightfully so. Archibald Lake Wilderness Area covers 684 hectares and includes old-growth forest, hardwood drumlins, lakes and wetlands while supporting critical habitat for moose, providing clean water for Brook Trout and Atlantic Salmon, and breeding songbirds like Canada Warbler and Evening Grosbeak. It also provides excellent breeding habitat for the revered Northern Saw-whet Owl. With dense forests of Black Spruce, Balsam Fir, and Eastern Hemlock sprinkled with Paper Birch floating over deep beds of Sphagnum Moss, there are ample opportunities for small owls to find food and shelter.
Randy Lauff has been monitoring and maintaining a network of Northern Saw-whet Owl nest boxes in eastern Nova Scotia for over 20 years. When I saw his emails come through the Project Owlnet listserv that he was recording his greatest breeding season ever, I asked if he would be interested in allowing me to put a Motus tag on one of his breeding adult saw-whets. He excitedly obliged, and in less than a week I was on my way to Canada. Shortly after I arrived, we drove out to the active nest boxes and made a plan to capture the owls. The females were quite easy to catch, as they dutifully sat inside of their nest boxes incubating the eggs and protecting their nest. So when we raised a long-handled dip net up to the nest box entrance hole, the females tried to escape and gently plopped down inside of our trap. I then worked quickly to weigh and measure the owls, fit their legs with a standard aluminum band, and attached the Motus tag to the owls. In less than 30 minutes, the females were released and they flew back to their nest box and resumed the incubation process. This work represents the first Motus tagged Northern Saw-whet Owls in eastern North America known to have an active nest!
After I returned from my trip to Nova Scotia, it was only four days until I left again. My destination on this trip? Lake Superior, Michigan. Since the mid-2010s, owl banders Chris Neri and Nova Mackentley have documented a phenomenon seen nowhere else on this side of the Mississippi River. They have regularly caught and banded over 200 juvenile Northern Saw-whet Owls every summer, starting July 1 and ending in mid-August. This is a significant breeding population that had never been noted before in the lower 48 states. Saw-whets will regularly breed in small numbers in the US, but mostly at higher elevations and found in the Rocky Mountains and Cloud Forests of New Mexico and Arizona. This breeding population in the UP of Michigan is seen nowhere else in the eastern United States. From July 1 – July 10, I traveled to Paradise, MI working with Chris and Nova to deploy 22 Motus tags on the saw-whets captured at their banding station.
Notice anything different about these saw-whets? Juvenile Northern Saw-whet Owls have completely different plumage than the adults! The first set of feathers that juveniles grow in are dark chocolate throughout the head and back, and the body is a golden-brown, like perfectly baked cookies. Incredibly, they will replace all of their body feathers within 12-16 weeks, and then appear just as the adults do. A tiny owl magic trick!
By tagging breeding owls, we hope to learn valuable information about how these secretive birds behave during and after the breeding season. Where do the owls go after they finish breeding? When do they leave their nest area? Will the owls breed in the same location next year? Where will they spend the winter? There are many questions that can be addressed using the revolutionary Motus Wildlife Tracking System, and WCT is very excited to once again be at the frontier of migration science.
This research is being conducted as the basis for my Master’s of Science thesis, where I am enrolled at the University of Delaware. Significant support comes from Project Owlnet, who has gracefully provided me with funding to purchase research materials, such as the Motus tags used on this trip.
