How to identify the Boreal Owl

To correctly identify the Boreal Owl (Aegolius funereus), check each of these features. Birds can be tricky: habit, habitat, and call often confirm a sighting that a single photo cannot.

Size at a glance

Length

22-27 cm (8.7-10.6 in)

Wingspan

50-62 cm (20-24 in)

Weight

90-215 g (3.2-7.6 oz)

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Adults have dark brown upperparts heavily spotted with white, and whitish underparts streaked with brown. The facial disc is whitish to grayish-white, bordered by dark brown, giving a surprised or stern expression. The crown is spotted with white. Flight feathers and tail are barred with white.

2. 2

   Beak shape

   Shape and color of the bill: a key field mark.

   Small, hooked, yellowish-horn colored beak, mostly concealed by facial feathers.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Bright yellow eyes.

4. 4

   Leg color

   Leg and foot color.

   Feathered legs and feet, typically grayish-brown.

5. 5

   Distinguishing features

   Standout features that separate this species.

   Large, round head without ear tufts; prominent whitish facial disc outlined in dark brown; small size; heavily spotted brown upperparts; bright yellow eyes.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Juveniles are uniformly dark chocolate brown on the head and upperparts, with a dark facial disc and a prominent white 'eyebrow' or supercilium. Underparts are also dark brown. They lack the white spotting of adults. This plumage is retained for their first summer.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   No significant seasonal plumage changes. Plumage remains consistent year-round for adults.

8. 8

   Sexual dimorphism

   How males and females differ.

   Females are generally slightly larger and heavier than males, but plumage is identical.

Key field marks

• Size and Shape. Small, compact owl with a relatively large, round head and no ear tufts. Short tail.
• Facial Disc. Prominent whitish to grayish-white facial disc, distinctly outlined in dark brown, giving a 'surprised' or 'stern' expression. This is a key field mark.
• Eyes. Bright yellow eyes, contrasting with the facial disc.
• Plumage Pattern. Dark brown upperparts heavily spotted with white. Whitish underparts streaked with brown. Crown is spotted, not streaked.
• Vocalization. Listen for the male's distinctive, rapid series of soft, flute-like hoots ('poo-poo-poo-poo-poo') during late winter and early spring nights.
• Habitat. Look in dense, mature coniferous or mixed forests, especially near clearings or wetlands, and areas with old woodpecker holes.

Explore the Boreal Owl