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Mountain Pygmy Owl (Glaucidium
californicum)
Description:
Male and female are identical in plumage. Except for a very limited area
in Southern Arizona. This is a diurnal owl (active in daytime); its
small size, plump shape, long narrow tail, bold white eyebrows, brown
streaks on white under parts, and white spotting on a brown head and
forehead make it very distinctive (the backside is also brown with
larger white spots). It has 2 black patches on its nape, outlined in
white, that vaguely resemble an extra set of eyes. It has a dark brown
tail with white bars; grayish-yellow bill (darker at the base); and
lemon yellow iris. The owl becomes more grayish-brown overall in the
Rockies and there is a red phase bird that is more cinnamon-brown
overall. This little owl is very bold and will often allow a very close
approach. Although it is not brightly colored, it very often brings a
crowd of mobbing songbirds along with it that will betray its location.
It also has a distinctive low evenly spaced toot (call) that makes
finding this owl among other daytime birds easier (regularly calls
although actively vocalizes most in March through mid-June and September
through October).
Young:
The young are similar in plumage to the adults. The young do not develop
their white markings until they mature. As a juvenile owl the white
spots on the crown are not developed.
Habitat:
The Northern Pygmy-Owl has a wide range of forested habitats. In its
western and Sierra range it is associated with blue oak savanna to
montane conifer forests. Its normal range is about 3000 - 6000 ft. in
elevation. It may move into lower elevation in the winter months and
alternately nest as high as 8000 ft. in the Sierras (it is rare on the
east slope of the Sierras) the highest frequency is at 4000 - 5000 ft.
in elevation. In the Rocky Mountains the Northern Pygmy may range as
high as 12,000 ft. and may also descend into lower prairie habitats well
away from forests. In general, the Northern Pygmy-Owl is found near
edges of meadows, lakes, burns, and other openings in the forest. They
will rarely or never be found in unbroken dense forests.
Food and Feeding:
The list of possible prey in the Northern Pygmy-Owl's diet is quite
large. This may include all of the small mammals, small to medium sized
birds, reptiles, larger insects, and amphibians within their range. The
Owl's preference seems to be mice, birds, and large insects with studies
indicating that about 90% of their diet is comprised of small mammals
and birds. This little owl is a bold and ferocious daytime predator. It
will kill birds such as Gambel's or California Quail that are more than
twice its weight.
Breeding:
The Northern Pygmy-Owl is seasonally monogamous. Nest sites are
typically found in woodpecker holes or dead tree cavities. Egg records
for this species range from late April through late June. Average clutch
size is 3 eggs but there may be as many as 7 or as few as 2; incubation
lasts 28 -29 days and the eggs are not incubated until the clutch is
complete. The young subsequently all hatch usually within 1 day. The
male feeds the incubating and brooding female for approximately 9 days
after eggs hatch at which time the female will begin to forage. Fledging
occurs at 23 -30 days although parental protection continues for 20 -30
days after the young fledge. Signs of sexual maturity begin to show at
only 5 months although the age of the first breeding is probably 1 year.
Movements:
There is no known migratory movements of this owl. The Northern Pygmy is
believed to be largely sedentary. Except for winter downslope movements
and juvenile dispersals there are no further records
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