We’re pleased to announce the first newly tagged owl of the season — a heavily marked juvenile female we’ve nicknamed Alderbrooke, trapped and relocated from the Montréal airport.
Trapped and relocated twice, in fact; much as with Dorval last year, Alderbrooke as proven to be a persistent boomerang. She was initially trapped Dec. 9 by Julie Lecours of Falcon Environmental, which provides wildlife services at the airport, and with whom we have been collaborating to study the behavior of relocated airfield owls.
Alderbrooke was tagged by Rebecca McCabe, our Ph.D. candidate at McGill University who is using SNOWstorm’s immense dataset to answer a lot of questions about the winter movement ecology of snowy owls — including best practices for moving them from airports so they stay moved. (Becca’s work is partially funded by Bird Protection Québec, and Alderbrooke is named in honor of one of that organization’s sanctuaries.)
Once she had tagged Alderbrooke, Becca moved the owl to one of her predetermined release sites, chosen for varying distances, directions and quality of habitat as part of the relocation study. This one was near Glen Robertson, Ontario, 60 km (37 miles) to the west of the airport. Becca said she was hopeful Alderbrooke would settle down there, since she saw other rodent-specialist raptors, including a rough-legged hawk, hunting the area.
Alderbrooke had other ideas. She beelined back to the airport Dec. 14, and took a few more days for FE biologists to catch her a second time, on Dec. 19. She was in good shape, and the same weight as when she was originally trapped. This time Becca took her across the St. Lawrence to Chouette à voir, in Saint-Jude, Québec, about 70 km (43 miles) east-northeast of the airport — the same farming area where Dorval, Otter and Yul wintered last year.
This time, it seems to be working. At her last transmission on Dec. 24, Alderbrooke had made an 80-km (47-mile) exploratory flight east, then doubled back about half way to near Upton, QC. We’ll have an interactive map for her ready in a few days, and we’ll post to social media when it goes up.
By the way, there was a recent question in the blog comments about how snowy owls are trapped. There are a couple of methods we routinely use. Alderbrooke was originally caught using a bownet, which is basically a giant, spring-loaded net, usually circular, about four feet wide and hinged in the middle. A small cage with a pigeon, hamster or gerbil is placed in the center for a lure. Bownets are the bread-and-butter trap for biologists who catch large raptors.
When she was retrapped, it was using a different technique known as a verbail trap — a gizmo that affixes to the top of a short post. When the owl lands on the post (attracted by a caged lure animal at its base), the trap harmlessly snugs a soft cord around both legs above the feet, sliding the owl to the ground for a few moments until the bander arrives. Many banders also use some version of a bal-chatri or phai trap, ancient designs originally incorporating horsehair nooses around a caged lure, but today using heavy monofilament or braided nylon fishing line to hold the owl’s foot as it reaches for the caged lure. All are safe and have been used for — well, for centuries, to trap wild raptors.