Northern Saw-whet Owl visits Suburban Garden

Nature Notes for October 30, 2015

“There’s a small owl on my deck. It’s been there for a couple of hours. What is it doing there? Do you think it’s all right?” said the worried voice on the telephone.

The first questions I asked were to try to identify the owl species: How big is it? Does it have ear tufts? Since it was described as quite small and without ear tufts, my best guess was that it was a Northern Saw-whet Owl.

These tiny owls weigh between 80 and 100 grams. As with all owls, the females are larger than the males. Because of its small size, many people describe it as a “baby owl”, but that’s a big as they get.

Northern Saw-whets are one of the few owl species occurring in this area that migrate regularly. Some other owl species irrupt south in some winters, usually due a shortage of food at more northern latitudes. Saw-whets, however, migrate south in winter and back north again in the spring. If the hunting is good, a few will stay around in Northumberland County through the winter. There have been recoveries of saw-whets, banded in Northumberland, from as far south as southern Virginia.

These little owls are highly nocturnal so they are seldom seen by observers. During the day, these owls roost in dense cover, so they are difficult to detect. There is a sub-set of bird banders that become nocturnal during the migration period in order to capture and band saw-whets. Much of the knowledge of their biology, including migration routes, comes from these studies.

Early settlers gave this owl its curious name because they thought the song was like the sound of a saw being whetted or sharpened. It has a repetitive one-note song, which it sings in the early spring (late February to early April), around the time the maple syrup is running.

Saw-whet owls nest in tree cavities and will use nest boxes.

So what was the bird doing in a Cobourg backyard in the daytime? It was probably trying to keep as still as possible, to avoid being prey for larger birds. Even at night, saw-whets can be at risk, since big owls will eat little owls if they get a chance.

A neighbouring backyard had bird feeders. Perhaps the saw-whet was waiting for an opportunity to feed, too. They do prey on small birds. Often, the spilled seed from bird feeders attracts small rodents which would also be the perfect size of prey for a saw-whet owl.

A few years, ago, our garden was visited by a saw-whet owl in the spring. In the pre-dawn light, it tried to attack a Mourning Dove under the feeder, but was unsuccessful. Later in the morning, our attention was drawn to its roosting place by a flock of scolding chickadees. This bird spent half the day in the yard and delighted several visitors.

Although a few Northern Saw-whet Owls nest locally, most are hatched from nests in the boreal forest. It is possible that this stop in Cobourg was the bird’s first encounter with people. It didn’t yet know that it might be wise to be cautious around humans.

The Project FeederWatch season begins on November 14, 2015. For more information, go to www.birdscanada.org/feederwatch.