The northern saw-whet owl is the most nocturnal of Missouri's owls, and the smallest, as well. The upperparts are brown with white spots, and the underparts are white with heavy reddish streaks. The head appears large for the body; the eyes are yellow, the bill dark; the forehead is brown with white streaks. There are no tufts on the head. Voice is a monotonous series: "too, too, too . . ." that is usually given on the breeding ground (and thus rarely heard in Missouri), or a rasping squeal like a saw blade being sharpened.
Similar species: Our other common small owl, the eastern screech-owl, is larger and less rounded, is grayer, and has small ear tufts. Our other owls that have rounded head profiles are much larger.
Length: 8 inches (tip of bill to tip of tail); wingspan: 17–18 inches.
Northern half of the state, though casual statewide.
Habitat and Conservation
Hunts over open country at night. Finds seclusion during day in dense evergreens, among vines, or in tree cavities. On the rare occasions it is seen, it is usually perched near the ground in dense cover or in the entrance of a tree cavity.
Insects, shrews, bats and small birds.
Rare winter resident (in northern Missouri), casual in the rest of the state. Some years they are more numerous than in others, when there has been a food shortage in their usual range that has forced them into our state. In these "invasion" years, they may stay and nest in Missouri, though they are difficult to find; listed as an accidental summer resident.
Usually present in Missouri from late October through the middle of March; then they migrate north to forests in the Great Lakes region and into Canada for summer breeding season. They nest in tree cavities, often where another bird has nested before. Clutches comprise 4–7 eggs, which are incubated for 26–29 days. After hatching, they remain at the nest for about a month before fledging.
This species is difficult to study because of its secretive habits, but biologists suspect their numbers are declining. Loss and fragmentation of mature forest habitat no doubt is a problem for them. In their breeding territory, people can help by putting up nest boxes and allowing dead trees (which can provide nesting cavities) to remain.
Like several other owls, this species requires a tree cavity in which to nest. They don't excavate their own cavities; instead, they nest in holes that had previously been drilled out and used by woodpeckers. Thus their reproductive success depends not only on mature forests with plenty of standing, dead trees, but also upon healthy woodpecker populations.