The willow ptarmigan (Lagopus
lagopus) is a bird in the grouse subfamily Tetraoninae of the pheasant family
Phasianidae. It is also known as the willow grouse and in Ireland and Britain,
where it was previously believed to be a separate species, as the red grouse.
It is a sedentary species, breeding in birch and other forests and moorlands in
northern Europe, the tundra of Scandinavia, Siberia, Alaska and northern
Canada, in particular in the province of Newfoundland and Labrador. It is the
state bird of Alaska.
In the summer the birds are
largely brown, with dappled plumage, but in the winter they are white with some
black feathers in their tails (British populations do not adopt a winter
plumage). The species has remained little changed from the bird that roamed the
tundra during the Pleistocene. Nesting takes place in the spring when clutches
of four to ten eggs are laid in a scrape on the ground. The chicks are
precocial and soon leave the nest and while they are young, both parents play a
part in caring for them. The chicks eat insects and young plant growth while
the adults are completely herbivorous, eating leaves, flowers, buds, seeds and
berries during the summer and largely subsisting on the buds and twigs of
willow and other dwarf shrubs and trees during the winter.
Willow ptarmigan have chunky
bodies, ranging from 28 to 43 cm long, and weighing and average of 0.57 kg.
They have short legs with feathered toes, a feature that enables them to
navigate through loose snow. They have short tails (with an average of 118 mm
or more for males and 116 mm or less for females) and wings (when folded, an
average of 190 mm or more for males and 190 mm or less for females).
Willow ptarmigan molt seasonally.
Their winter plumage is usually complete by November, depending on the
geographic region of the population. It consists of white feathers covering the
entire body except the tail, which remains black. However, the tail is often
covered by other feathers on the body, making the bird appear completely white.
When the spring arrives, the females’ plumage becomes a mottled brown and
ochre, while the males have a rusty hazel or chestnut coloring with darker
brown barring on the entire body except for the wings and tail. They also have
red “combs” on their eyes which are generally more visible during the warmer
months. During the fall, the plumage of both male and female willow ptarmigan
becomes lighter, with the females’ plumage becoming more gray and white. The
males keep the dark barring pattern but take on more ochre tones.
Copyrights (Tim Grams)
Red grouse
populations of Scotland and Ireland do not develop the same white winter
plumage as willow ptarmigan populations living in more northerly areas of
Europe and North America (which are covered by snow for much of the year).
Instead, they retain a plumage that is predominantly dark reddish-brown. This
is likely due to the fact that populations in Ireland and Scotland are exposed
to a milder maritime climate than populations living inland and further north.
Some studies have also found that there is a possible trade off between white
winter camouflage and the thermal benefits of keeping a darker plumage for better
heat absorption. However, it has also been found that white plumage has
physical characteristics that allow for slightly better insulation. For this
reason, more studies must be done to determine whether or not white plumage is
thermally disadvantageous. ("Ptarmigans", 1974; Johnsgard, 2008;
Lethbridge College Virtual Wildlife, 2009).
Call of the Willow Ptarmigan
The species is
found primarily in Arctic tundra, extending south in alpine mountain ranges and
along or below the tree line, in openings of boreal forest. It prefers low,
moderately moist areas with low shrubs, mosses, grasses and herbs avoiding
rocky or lichen-rich tundra and steep slopes. Males prefer territories in areas
with vegetation lower than eye level and elevated sites such as rocks, trees or
hummocks for displaying on. Generally laying occurs in May and June. It
normally lays eight to eleven eggs. The nest is a shallow scrape with a thin
lining in thick vegetation which usually partially covers it. It feeds on buds
and twigs of Salix and birch (Betula) in winter. From spring to autumn leaves
and berries of Vaccinium and Empetrum are important parts of its diet. It is
sedentary in the U.K. and Scandinavia, only making short-range altitudinal
movements, but at least partially migratory elsewhere (de Juana et al. 2016).
This species
has an extremely large range, and hence does not approach the thresholds for
Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2
combined with a declining or fluctuating range size, habitat extent/quality, or
population size and a small number of locations or severe fragmentation).
Despite the fact that the population trend appears to be decreasing, the
decline is not believed to be sufficiently rapid to approach the thresholds for
Vulnerable under the population trend criterion (>30% decline over ten years
or three generations). The population size is extremely large, and hence does
not approach the thresholds for Vulnerable under the population size criterion
(<10,000 mature individuals with a continuing decline estimated to be
>10% in ten years or three generations, or with a specified population structure).
For these reasons the species is evaluated as Least Concern.
A willow
grouse posing for the photographer in the
heart of Finnish Lapland
Photo location: Inari, Finland
Photo info - 14.02.2015:
Canon EOS-1D X, 150 mm, ISO 2500, f 4, 1/250 sec, Flash: not used
Tags: markus varesvuo,
snow, wildlife photography, Willow Grouse, winter
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