| Species: Northern Shrike
Lanius excubitor
The Northern Shrike
or ‘butcher bird’ is a predatory songbird which feeds on small
mammals, birds and insects, sometimes caching the prey at a larder
by impaling them on thorns or barbed wire fences.
It breeds in the
taiga and tundra generally north of 55 degrees northern latitude in
North America and 50 degrees northern latitude in northern Europe
where it is known as the Great Grey Shrike. In North America it
winters in southern Canada and the northern United States.
General:
Great Grey Shrikes are medium-sized songbirds around 24 to 25 cm and
weigh 60 to 70 grams.
Sexes Similar:
The general colour of the upperparts and back is gray, the cheeks,
chin and thin supercilium are white, and a deep black mask extends
from the base of the bill through the eye to the auricular. The
wings are black with a white wingbar made up by the bases of the
primaries. The tail is long, black with white outer tail feathers.
The bill is large and hooked at the tip. The legs and feet are
blackish.
Males and females are about the same size, and do not differ
conspicuously in appearance.
Juvenile:
Similar to adult, but juveniles are tinged brownish on the upperside
and wings and have sharp and distinct barring on the breast with a
less distinctive mask.
Similar Species:
Loggerhead Shrike is smaller overall with a larger head – loggerhead
means ‘large headed’ – the all black bill of the Loggerhead Shrike
is smaller and the mask usually extends all the way across the
forehead. Northern Mockingbird is similarly coloured but the narrow
pointed bill and lack of a mask immediately distinguishes it.
Behaviour:
Adopts a ‘wait and attack’ approach from an exposed perch and then
seizes prey in an aerial dive near the ground with its feet or bill.
Often impales prey on thorns, spines, or barbed wire. much in the
way butchers hang meat in their shops, hence the name ‘butcher
bird’. Mice, small birds, and large insects form the bulk of the
shrike's diet.
Habitat:
Breeds in taiga and at the border of taiga and tundra, in open
country with medium or tall trees or shrubs. Winters in open country
with tall perches, including shrubby fields, wetlands, and forest
edges.
The Northern Shrike
kills more prey than it can immediately eat or feed to nestlings.
Such behavior was characterized by early observers as "wanton
killing," but the Northern Shrike stores excess prey to eat later an
adaptation for surviving periods of food scarcity.
Both male and female Northern Shrikes sing throughout the year and
males sing especially in late winter and early spring.
The Northern Shrike sometimes tries to attract small songbirds by
mimicking their calls in an attempt to catch them for food.
The longevity
record for Northern Shrike is only 3 years and 3 months although
more study is needed in respect of the life history of this species.
Conservation Status: (Least Concern)
Populations are thought to be stable but trends are difficult to
assess because of the Northern Shrike's rarity and remoteness of its
breeding habitat in the boreal forest and tundra. Large areas of
suitable breeding habitat are protected in Alaska and northern
Canada which may help with the conservation status.
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