Northern Pygmy Owl - Glaucidium californicum
Formerly grouped with Glaucidium gnoma
Calls - Glaucidium californicum
Northern Pygmy Owls have also been called Pygmy Owl, Rocky Mountain Pygmy Owl,
Vancouver Pygmy Owl, California Pygmy Owl, and Dwarf Owl.
[For help with terms used in the description, see parts of an owl. For general characteristics common to most owl species, see owl physiology.]
Description: The Northern Pygmy Owl is a tiny, woodland, diurnal Owl that
is most active between dawn and dusk. They have greyish or brownish or reddish (3 morphs)
upperparts and light belly that is boldly streaked with brown. The head and nape are
liberally sprinkled with whitish dots (more cinnamon or buff on red morph). On the nape
are 2 distinctive, vertical black patches that resemble an extra pair of eyes. The
relatively long tail is distinctly barred with 6 to 7 light stripes. Eyes are yellow, bill
is yellowish-horn, and the toes are greyish-yellow.
Juveniles are similar to adults but with unspotted and greyer heads, and fluffy plumage.
Size: Length females 18.5cm (7.3"), males 16.5cm
(6.5") average. Wingspan 380mm (15") average.
Habits: Northern Pygmy Owls are very secretive and tend to perch and roost in thickets where it is safe from predators. At times, one will sit atop the highest spire of a tree. At rest, a Northern Pygmy Owl sits with its tail cocked away from vertical, and often twitches its tail when excited. A Northern Pygmy Owl's flight between perches is short and rapid - plummeting downwards as it leaves a perch before levelling off, and swooping up to the next. If the next perch is a tree, it will tend to land low, then moves up through the tree to a higher perch. Flight is relatively noisy for an owl, and resembles a shrike, with rapid wing beats and rounded wing tips.
Weight females 73g (2.6 oz), males 62g (2.2 oz) average.
Despite their small size, Northern Pygmy Owls are quite fierce, and will attack prey or drive off intruders several times their own size. When one of these owls is threatened, it will puff up its feathers and spread its tail to make itself look larger. When hiding, it tries to look thin, faces the danger, and closes its eyes into slits.
Voice: The primary call of the male is a series of repetitive, whistled
hoots "too-too-too-too-too-too-too" at intervals of 1
to 2 seconds, although it is reported that this can vary from 0.5 seconds, all the way up to 4 seconds. This call is territorial in nature and is usually given in the early evening
and before dawn, and may be heard year-round. The male gives a high whinnying sound when
bringing food to his mate. The female calls much less often and it has a cackling quality.
Other calls include an ascending staccato series of whistles. When excited, they may emit
a high-pitched trill (8 notes/second).
Hunting & Food: Northern Pygmy Owls are "sit and wait" predators, that hunt mainly by vision, diving down onto prey on the ground and driving the
talons into the prey's throat. they will also attack birds in shrubs, crashing into the
hapless victims. Most prey is carried off in the feet to feeding sites. Birds are usually
plucked before being consumed. They often eat only the brains of birds and the soft
abdomen of insects! One of these little owls can carry prey weighing up to 3 times its own
The Northern Pygmy Owl feeds on a wide range of small prey including small mammals, birds,
and reptiles and amphibians. Voles make up the bulk of their diet, with birds comprising
most of the rest (mainly songbirds, but as large as a California Quail). Other small
mammals include shrews, mice, chipmunks, bats, moles, young rabbits, and weasels. Insects
may be very important when they are most abundant. Other prey taken are toads, frogs and
small lizards and snakes.
During winter, surplus prey is cached in a cavity, often in large quantities. These
caches help small owls like these meet their metabolic needs during very cold winter
periods. Summer caches are usually much smaller.
Pellets are very small, averaging about 3cm (1.2") long. They are formed only
occasionally as these owls don't consume large amounts of fur, feathers, or bone. The
pellets tend to fall apart shortly after ejection.
Breeding: Northern Pygmy Owls are unsociable birds, remaining solitary
much of the year. During courtship both sexes call to each other with their mating trill.
They also pass food to each other and snuggle closely.
There is no information on territory size, but the similar Eurasian Pygmy Owl has
territories from 200 to 1700 hectares (500 to 4200 acres), and the Northern Pygmy Owl
likely has similar-sized territories.
Northern Pygmy Owls are almost entirely dependent on old woodpecker cavities for nest
sites. They will also nest in natural tree cavities. Nest trees are usually dead and are
usually coniferous in the boreal forest and deciduous in more southern areas. Nest
cavities range from 3 to 23 metres (10 to 75 feet) above ground, averaging 6 to 7 meters
(20 to 23 feet). Eggs are laid between April and June, with clutch size ranging from 3 to
7 (3 - 4 average; may increase from south to north). The female does the incubating and
brooding while the male brings food and defends the nest. The incubation period is about
29 days. Unlike all other North American owls, The Northern Pygmy Owl begins incubation
only after the clutch is complete, so that young tend to hatch over a period of 1 to 2
days, rather than one every 1 to 2 days. Young grow quickly, reaching 60% of adult size
after 2 weeks. They fledge at about 30 days, when they are capable of flight. Fledglings
are then fed and defended by their parents for a further 20 to 30 days. Family groups tend
to break up in late Summer or Autumn. Northern Pygmy Owls are single-brooded. It is not
known if replacement clutches are laid. Nest cavities may be used for several consecutive
years by the same birds.
Mortality: No information on longevity or mortality currently
available. Potential predators of these owls are other owls, jays, crows, ravens, snakes,
Habitat: Northern Pygmy Owls inhabit open coniferous and mixed forests
from valley bottoms up to treeline. They do not inhabit dense, continuous forest. In all
areas they use forest clearings for hunting - along the edges of meadows, fields,
wetlands, and roadsides, and through old burns and logged areas. For roosting they prefer
quiet, shady alder thickets. During the breeding season they inhabit open forests with a
selection of snags with old woodpecker cavities.
Distribution: West North America, from British Columbia and southern
Alaska south through the Rock Mountains to California and Arizona, and possibly also to
the mountains far north Mexico.
Northern Pygmy Owls are essentially sedentary, except for altitudinal movements downslope
in winter. Southward irruptions during winter may occur in years of food shortage.
Distribution of the Northern Pygmy Owl Glaucidium californicum
Status: Uncertain, locally not rare.
Original Description: Sclater, Philip Lutley. 1857. Proceedings of the Zoological Society of London (PZS): Pt. 25, no. 327, p 4.
G. c. californicum,
G. c. grinnelli,
G. c. pinicola,
G. c. swarthy
Campbell, Wayne. 1994. "Know Your Owls (CD-ROM)". Axia Wildlife
Page compiled by Deane P. Lewis. Page last updated 2012-08-13
OwlPages.com Owl Species ID: 190.040.000