Northern Saw-whet Owl Biology

A Reference for North and Central American Owls

Name: Northern Saw-whet Owl – Aegolius acadicus
Other Common Names: Acadian Owl (acadicus); Queen Charlotte Owl (brooksi); Kirkland’s Owl; Saw-filer; Whetsaw; White-fronted Owl; Sparrow Owl.

Subspecies: There is only one recognized race of Northern Saw-whet Owl on mainland North America and Mexico. There is another recognized race that is restricted to the Queen Charlotte Islands of British Columbia. These are the only two races of Northern Saw-whet Owl. The Saw-whet Owls are found nowhere else in the world but there is another species of Saw-whet Owl found in Central America (Unspotted Saw-whet Owl – Aegolius ridgwayi) that appear somewhat similar to the deep brown brooksi race of the Charlotte Islands.
A. a. acadicus is found from Southern Alaska south to Southern California and New Mexico. It also stretches from British Columbia to the East Coast of Canada and through the Northeastern U. S. In its winter range the Saw-whet stretches across the Southern U. S. and into some of Northern Mexico. There are also resident birds in the Central Mexican Highlands.

Measurements and Weights:
Wingspan: 17 – 20 in.
Length: 7 – 8.5 in.
Tail: 2.5 – 2.9 in.
Average Weight: Male: 2.7 oz.
Average Weight: Female: 3.25 oz.

Description: This is a small owl that lacks ear tufts. The Saw-whet has a proportionately large head and prominent facial disk. The color of the Saw-whet varies as far as the amount of cinnamon or red tones in its rich dark brown backside. It has scattered large white spots on its nape and backside (scapulars, primaries, and secondaries). Its crown has fine white streaks and the tail has 2 to 3 broken white bars. Its under parts are white with thick reddish-brown streaks (noticeably more reddish or cinnamon in color than the backside). The prominent facial disk varies in its amount of white in the disk although can be a light tannish-brown. Above bill and eyebrows white sometime referred to a conspicuous white “V” from the base of the bill up and over the eyes (the amount of white in the disk also determines how obvious this is). The bill is black and the iris is lemon yellow. The brooksi race is darker, has fewer white markings, and orange-buff under parts. The noticeable distinctions between the similar but slightly larger Boreal Owl (that often inhabits the same range) are: the Saw-whet’s black bill and Boreal’s yellow bill; the streaks on the Saw-whet’s crown versus spots on the Boreal’s; the Saw-whet also lacks the black outer facial rim of the Boreal Owl.

Young: The juveniles lack the white marking on the backside except for small amounts on the wings and tail. The undersides (lower chest, flanks, and belly) are tan to light brown. The upper chest and head are darker brown (appears to be wearing a dark brown hood). The facial disk is black or brownish-black. Strong contrasting white above the bill and into the eyebrows (bold white “V”). Variable amount of white also below the eyes, sides of the bill (cheeks), and into the mustache.