Photo: Greg Schechter/Flickr Creative Commons

Boreal Owl

Aegolius funereus

A rather mysterious owl of dense northern woodlands. Except when calling at night in very early spring, it is easily overlooked. Until the 1970s it was not known to breed anywhere south of Canada; recent explorations have shown that it is a resident in many mountain ranges in the western United States, nesting in forest at the highest elevations. In the northeast, winter invasions sometimes bring a few Boreal Owls south to areas frequented by birders.
Conservation status Northern populations in North America probably face no immediate threats. Status of western mountain populations still not well known.
Family Owls
Habitat Mixed-wood and conifer forests, muskeg. Nests mostly in forests where coniferous trees such as spruce or fir are mixed with deciduous trees including aspen or birch. Such habitats are found at low elevations in the north, only in high mountains toward the south. During winter invasions, usually found in groves of conifers.
A rather mysterious owl of dense northern woodlands. Except when calling at night in very early spring, it is easily overlooked. Until the 1970s it was not known to breed anywhere south of Canada; recent explorations have shown that it is a resident in many mountain ranges in the western United States, nesting in forest at the highest elevations. In the northeast, winter invasions sometimes bring a few Boreal Owls south to areas frequented by birders.
Photo Gallery
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  • adult
  • fledgling
  • adult
Feeding Behavior

Hunts mostly at night (although nighttime is not entirely dark in summer in far north). Hunts by moving through forest from one perch to another, watching for prey, then swooping down to take prey in its talons. Can capture prey hidden under snow or under dense vegetation, because ears are adapted for precise location of sounds.


Eggs

3-4, sometimes 2-5 (European birds may lay more eggs). White. Incubation is by female only, 26-32 days. Young: Female remains with young most of time at first; male brings food, female feeds it to young. After about 3 weeks, female also hunts and brings back food. Young leave nest about 28-36 days after hatching, are fed by parents for at least 2 more weeks.


Young

Female remains with young most of time at first; male brings food, female feeds it to young. After about 3 weeks, female also hunts and brings back food. Young leave nest about 28-36 days after hatching, are fed by parents for at least 2 more weeks.

Diet

Mostly small mammals. Feeds mostly on voles and mice, also small squirrels, shrews, pocket gophers. Also eats small birds of various kinds, and insects, especially crickets.


Nesting

Beginning in late winter or early spring, male sings at night to defend territory and attract female. In courtship, male feeds female. Male sings at potential nest holes, and female apparently makes final choice of site. Nest site is in cavity in tree, usually old woodpecker hole (Northern Flicker or Pileated Woodpecker) or natural hollow, 20-80' above ground. Also will use artificial nest boxes (some populations in northern Europe nest mostly in boxes). Usually chooses new nest site each year.

Illustration © David Allen Sibley.
Learn more about these drawings.

Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Apparently no regular migration, but stages irregular invasions south of nesting range during some winters, probably when food is scarce on breeding grounds.

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Migration

Apparently no regular migration, but stages irregular invasions south of nesting range during some winters, probably when food is scarce on breeding grounds.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon
Songs and Calls
Rapid series of whistled notes.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How climate change could affect this bird's range

In the broadest and most detailed study of its kind, Audubon scientists have used hundreds of thousands of citizen-science observations and sophisticated climate models to predict how birds in the U.S. and Canada will react to climate change.

Learn more

Read more: climate.audubon.org
Owls

Boreal Owl

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season.

More on reading these maps.

Each map is a visual guide to where a particular bird species may find the climate conditions it needs to survive in the future. We call this the bird’s “climatic range.”

The colors indicate the season in which the bird may find suitable conditions— blue for winter, yellow for summer (breeding), and green for where they overlap (indicating their presence year-round).

The darker the shaded area, the more likely it is the bird species will find suitable climate conditions to survive there.

The outline of the approximate current range for each season remains fixed in each frame, allowing you to compare how the range will expand, contract, or shift in the future.

The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

You can play or pause the animation with the orange button in the lower left, or select an individual frame to study by clicking on its year.

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season. More on reading these maps.
Winter
Summer

Winter Range
Summer Range
Both Seasons
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