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WHITE-HEADED WOODPECKER
Picoides albolarvatus
Family Picidae - Woodpeckers
Order Piciformes - Woodpeckers and Allies
Risk Status
Official status
The White-headed Woodpecker is rare throughout the northern part of
its range. It is currently on British Columbia's Red
List (CDC = G4 S1). In 1992 COSEWIC
designated it as Endangered (2000).
Image Credits: lower sketch by Rob
Cannings in Birds of the Okanagan Valley, British Columbia,
Campbell et al., 1987. Top photo and middle sketch in The Birds
of British Columbia, Campbell et al., 1990.
Historical facts
The British Columbia population of the White-headed Woodpecker
fluctuated widely over the last fifty years. The species was considered
very rare in the late 1950s and early 1960s, but became fairly common
in late 1960s and early 1970s. In the late 1970s, numbers declined
again for unknown reasons. The British Columbia population was under
100 birds when last surveyed in 1990. The last nest was found in
1980.
Distinguishing features
The White-headed Woodpecker, a member of the family Picidae, is
our only woodpecker with a white head and wing patches (males have
a red patch on the nape of the nape), contrasting sharply with the
black of the remaining plumage. This woodpecker can be mistaken
for no other bird; young resemble the adults, but are dull in colour
and have shorter bills. Young males and females sometimes have reddish
markings on the head as does the adult male.
Distribution
Map
Red dots indicate specimen records or confirmed breeding sites.
British Columbia
In Canada, the White-headed Woodpecker is found only in British
Columbia, where it is a very rare resident in the Okanagan Valley
from Naramata south, and casual (not reported annually) in the Similkameen
Valley, Grand Forks area, and the Kootenays. All breeding records
to date and about 90 percent of all sight records in this province
have been from the southern Okanagan Valley.
North America
The White-headed Woodpecker is resident in coniferous forests from
extreme southern British Columbia, south through eastern Washington
and northern Idaho to southern California and Nevada.
Habitat
The White-headed Woodpecker requires mature ponderosa pine stands
restricting it, more or less, to the benches and hills of the Okanagan
Valley below 600 or 700 m. They have also been found in ornamental
gardens, mixed ponderosa pine/Douglas-fir forest, Douglas-fir forest,
Engelmann spruce/lodgepole pine forest and black cottonwood stands.
Why is it endangered?
The primary limiting factor for populations of the White-headed
Woodpecker in Canada is the dependence of the species on mature
to old-growth ponderosa pine forests. This dependence is likely
related to both the availability of snags for nesting and roosting
as well as the availability of cones for foraging.
Most of the old-growth ponderosa pine forests of British Columbia
were heavily logged in the 1930s and 1940s and only scattered remnants
remain, usually in sites with difficult access. Some of these inaccessible
trees have been harvested by helicopter-logging.
If White-headed Woodpeckers are dependent on large pine seeds
as food in late summer, fall and winter, it is the availability
of this resource which may be the most important limiting
factor to its population. Ponderosa pines produce good cone
crops only every four to five years in the Pacific Northwest, and
no other suitable pine species are found throughout the northern
part of the White-headed Woodpecker's range.
Seed production by ponderosa pines also is related to the age
and size of the trees and the density of the stand; almost all seeds
are produced by large, dominant trees in open situations. As a result
of logging and subsequent fire suppression, many ponderosa pine
forests in the Okanagan Valley are now characterized by dense stands
of young trees, presumably resulting in poor seed production overall.
Reduced snag densities after selective logging also limits White-headed
Woodpecker nesting habitat, and if they resort to nesting low in
snags or smaller trees, this may make nests more accessible to predators.
Since insects are an important food source for White-headed Woodpeckers,
particularly in the summer, pesticide application in ponderosa pine
forests likely has a significant impact on woodpecker populations.
Biology
Breeding
White-headed Woodpeckers can raise three to five young per year.
The only closely examined British Columbia nest contained four round
white eggs. It is estimated that eggs are present from the first
week of May to the fourth week of June, and young from the fourth
week of May to the third week of July. Young have been reported
out of the nest from the beginning of July onwards, with some young
fledging as early
as the third week of June. There is no evidence for more than one
brood per season.
Nesting has occurred in Douglas-fir snags
but ponderosa pine is more frequently used, especially in winter.
The White-headed Woodpecker tends to nest in open-canopied stands
of mature and overmature trees. Grand fir, subalpine fir, and lodgepole
pine forests are of secondary importance. They build their nests
in the oldest, softest snags which are short, have large diameters
and no small branches. Nesting-holes are drilled low down in trees
which, while having a hard outer shell, are usually decayed and
soft inside. This woodpecker is not an accomplished driller, it
has a skull which is weaker than that of other woodpeckers, and
so is reliant on old decaying trees for nesting habitat.
Behaviour
White-headed Woodpeckers are
nonmigratory, although
post-breeding wandering, especially by young birds, probably occurs.
More than half of the British Columbia records from outside the
south Okanagan are from fall and winter. The minimum territory size
for the White-headed Woodpecker is about 8 hectares but considering
the low population densities in the northern part of its range,
territory sizes in British Columbia likely are much larger.
The voice is described as a single "wick" or
when excited the female calls " 'cheep-eep-eep-eep'
very fast and repeats the call every few seconds. The male under
similar circumstances calls 'yip, yip, yip, yip' in a much
shriller tone, but slower.
Diet or Growing requirements
Unlike other woodpeckers, the White-headed Woodpecker subsists on
vegetable matter, with about 50 per cent of the diet consisting
of ponderosa pine seeds; and the remainder consisting of ants, an
assortment of insects, and spiders. When foraging for insects on
conifer trunks or branches, they flake and chip bark away with angled
strokes rather than drilling the wood directly, using the bill as
a pry-bar. In summer, they feed by gleaning
insects from needle clusters rather than drilling and excavating.
In British Columbia, White-headed Woodpeckers have been observed
feeding on stalks of great mullein, a common weedy plant in disturbed
areas in the southern interior. These birds were presumably eating
the seeds of this plant, but may have been searching for insects
as well. They also are known to eat suet.
Predators
No information is available at this time.
Sources for more information
Related On-line Sites to Visit
Publications
Status Report, Wildlife Bulletin No. B-80, March 1995, R.J. Cannings
Birds of the Okanagan Valley, Cannings, 1987, p. 240
The Birds of British Columbia: the Woodpeckers, Crows and their
Allies, Guiguet, RBCM, v. 6, 1978.
The SOCAP Workshop Summary, The Nature Trust, 1989
Habitat Conservation fund, August 1992
Museum Specimens
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