Northern Saw-whet Owl (Aegolius acadicus)
The Northern Saw-whet Owl is a very small, short-bodied owl with a relatively short tail. The overly large head has no ear tufts and may appear distorted due to an asymmetrical skull. European explorers first discovered this Owl in a North American colony called Acadia (now Nova Scotia). The Latinised word acadius refers to this territory. The common name “Saw-whet” comes from these Owls unique calls described below. The Saw-whet Owl is also called Acadian Owl, Blind Owl, Kirkland’s Owl, the Saw-filer, the Sawyer, Sparrow Owl, White-fronted Owl, Farmland Owl, Little Nightbird, Queen Charlotte Owl, and even the Whet-saw Owl.
The facial disc is brownish with a whitish zone around the eyes, forming radial white streaks towards the edge of the disc, and with a blackish spot between the base of the bill and the orange-yellow eyes. The bill and cere are blackish. The disc does not have a dark rim but does have a narrow edge of light and dark spots. The rest of the head is warm rusty-brown or grey-brown, and densely covered with white shaft-streaks, especially on the forehead. The mantle and the rest of the upperparts are rusty brown with white spots. Flight feathers are spotted white. The relatively short tail normally has three rows of white spots on both webs of the rectrices. Lower parts are whitish with broad reddish-buff streaks. Toes are slightly feathered with dark horn claws with blackish tips. Juveniles of this species are chocolate-brown above with underparts pale brownish or cinnamon-buff. The eyebrows, forehead and lores are white, forming a pale “X” on the dark face.
They have a body length of 7-8 inches, wingspan of 16.5-19 inches and a body weight of 2.3 – 5.3 ounces.
Saw-whet Owls inhabit coniferous and deciduous forests, with thickets of second-growth or shrubs. They occur mainly in forests with deciduous trees, where woodpeckers create cavities for nest sites. Breeding habitat is usually swampy or wet, rather than dry. Riparian (the interface between land and a river or stream) habitat is often preferred.
Saw-whet owls are nocturnal ambush predators just like their larger cousins the Boreal Owl. They will perch on branches and wait till prey starts to move around, then silently pounce on them. Their main prey are deer mice and meadow voles. They will also take shrews, chipmunks and red squirrel. They will also take small birds like chickadees, kinglets, sparrows and swallows.
(Note: Being nocturnal hunters they roost and sleep during the daytime. Finding a roosting owl it is always a thrill. Sometimes it is unbelievable that something so small can be such a successful hunter. You will first notice that great big yellow-orange eyes. When taking your Saw-whet photographs be sure to focus on the eyes.
If you see your Saw-whet Owl stretch up and become long and thin this is a defensive display when they are nervous. They are trying to make themselves look bigger than they are, it is a good idea to get your photographs and leave the owl to calm down and continue it’s sleeping. Once again do not remove any branches as these provide protection from larger predators.)
Northern Saw-whet Owls nest in old woodpecker cavities, (primarily those made by Pileated Woodpeckers or Northern Flickers) or in natural cavities. They will also take to nest boxes quite readily. Nest trees are often dead and nest heights average 4 to 6 metres above ground. Nesting occurs between March and July. They lay 3-7 eggs over a number of days. The female does all the incubation and the male brings food to her to maintain her strength. She will sit on the eggs for 21-28 days. Young fledge at 4 to 5 weeks, and may leave the nest individually every 1 to 2 days, until they have all left. The young owls are cared for by the parents for some weeks after they leave the nest. Sexual maturity is reached at 9-10 months old.
References: Cornell Labs of Ornithology, The Owl Pages, Wikipedia