Vancouver Avian Research Centre

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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.
Capture Rates

The Northern Shrike is a winter resident of Colony Farm. Capture rates (2010-2012; standardized as birds captured per 100 net hours) peak in October and November as birds arrive and occurrences during April reflect migration movement northward to the nesting grounds.

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