PROTECTION / THREATS / STATUS:
The populations of the Northern Shrike are suspected to be stable. The numbers may vary from year to year, depending on availability of small mammal prey.
The birds occur in large protected areas in Alaska and Canada, providing them suitable nesting habitat.
The Northern Shrike is not globally threatened and the species is currently evaluated as Least Concern.
Fr: Pie-grièche boréale
Ang: Northern Shrike
All: Taigaraubwürger
Esp: Alcaudón boreal
Ita: Averla settentrionale
Nd: Noordelijke Klapekster
Sd: nordlig varfågel
Photographers:
William Price
PBase-tereksandpiper & Flickr William Price
Simon Tan
PBase Bird galleries
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD Vol 13 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions – ISBN: 9788496553453
FIELD GUIDE TO THE BIRDS OF NORTH AMERICA - National Geographic Society - ISBN: 0792274512
BIRDS OF THE GREAT BASIN – by Fred A. Ryser - Univ of Nevada Pr -ISBN: 0874170796
South Dakota Birds and Birding – (Terry L. Sohl)
Atlas of the Breeding Birds of British Columbia
Native Animal of the Month: Northern Shrike
What Bird-The ultimate Bird Guide (Mitchell Waite)
Wikipedia, the free encyclopaedia
Northern Shrike
Lanius borealis
Passeriformes Order – Laniidae Family
INTRODUCTION:
The Northern Shrike was formerly a subspecies of the Great Grey Shrike - Lanius excubitor, but since 2017, it is classified as a distinct species.
It has very large range shared by five subspecies in both Old and New Worlds.
It breeds in subarctic and Arctic taiga-tundra with shrubs and low trees. It moves southwards to spend the winter in open country with sparse vegetation, grasslands, cultivated areas and deserts with some trees and shrubs.
It feeds on a variety of Arthropods and spiders, whereas in winter, the diet includes small mammals and birds. The largest prey are typically impaled on thorny vegetation or barbed-wire fences.
The Northern Shrike has stable populations but the numbers may vary, according to food abundance. But currently the species is not globally threatened.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 23-25 cm
Wingspan: 30-35 cm
Weight: 56-80 g
The Northern Shrike adult male has pale grey upperparts, nape and top of head, sometimes with variable bluish wash. Rump and uppertail-coverts are slightly paler. Scapulars are white.
On the black upperwing, there is a conspicuous white patch across the bases of the primaries, and another white patch is often seen at base of secondaries, but it is narrower. Both flight-feathers and tertials are tipped white. The long, rounded tail is black with white outer pair of rectrices.
The underparts are white, often with indistinct, fine grey barring or vermiculations on breast and flanks.
On the head, top and nape are pale grey. A white, narrow supercilium extends to the forehead. The conspicuous black mask extends from the lores through the eye to the rear of the ear-coverts. Cheeks, chin and throat are whitish.
The hooked bill is black. The eyes are dark brown. Legs and feet are blackish.
The female resembles male but she has less white with smaller wing patches, narrower tips of wing feathers, and slightly greyish scapulars. The underparts are greyer, sometimes with vermiculations on the upper breast. Wings and tail are smaller than in male.
The juvenile is often more brownish-grey with faint, narrow, dark brown barring on the upperparts from nape to upperwing coverts. The greater coverts show pale tips.
The underparts are whitish, with grey-brown tinge on breast and flanks, and narrow, brown vermiculations.
The mask is browner. The bill is brownish-grey.
SUBSPECIES AND RANGE:
The Northern Shrike has five subspecies, although some authors may also include L.b. invictus, but this one interbreeds with the nominate race L.b. borealis in Manitoba and Ontario, and is sometimes synonymized with it.
L.b. borealis (described above) breeds in Alaska and N Canada, S to extreme N British Columbia and Alberta, N Ontario and Quebec. It winters in S Canada and N United States.
L.b. sibiricus breeds in C and E Siberia, N Mongolia and SE Russia. It winters in SC Siberia, Mongolia, NE China and Ussuriland.
This race has ochre tinge on the upperparts and faint vermiculations below.
L.b. bianchii breeds in Sakhalin and S Kuril Islands. During winter, it is found in N Japan, Hokkaido.
This one is small, paler and greyer then “sibiricus”. It is less buffy above and less vermiculated below.
L.b. mollis breeds in CS Russia and NW Mongolia. Non-breeding in N China.
This race is darker than “sibiricus” and the wing patch is smaller. The underparts show more buff and stronger vermiculations.
L.b. funereus is found in S and E Tien Shan, and possibly E Kazakhstan.
This one is larger than other subspecies. It is darker than “mollis”, with more brownish-grey underparts and stronger vermiculations.
HABITAT:
The Northern Shrike breeds throughout taiga and taiga-tundra ecotone of Alaska and Canada where it can find trees and /or shrubs, but also open country. It also nests in patches of willows, alders and poplars that extend beyond the spruce line into the tundra zone.
During winter, it frequents mainly wetlands and estuaries, forest edges, savannas and agricultural fields with some trees and shrubs, and perching posts such as fences and powerlines.
CALLS AND SONGS: SOUNDS BY XENO-CANTO
The calls of the Northern Shrike include a raspy shriek and a crisp “beek”. The alarm call is a series of raspy “aak” and rapidly repeated “jaa”.
Male and female sing all year round, but less often in autumn and winter. The song is a long sequence of musical notes and phrases. It is very complex with mix of chatters, warblers, trills, gurgles and whistles, and also harsh notes. The song may also include mimicry of other bird species.
BEHAVIOUR IN THE WILD:
The Northern Shrike feeds on invertebrates in summer, such as Orthopterans, Coleopterans, Hymenopterans, Dipterans and also spiders.
During winter, if feeds mainly on small mammals especially rodents (mice and voles), and birds of various size, from doves, woodpeckers and jays to smaller species such as sparrows, warblers, buntings, kinglets, chickadees and others. It may sometimes eat carrion and suet at bird feeders.
The shrikes of Eurasia are known to eat lizards, frogs and snakes.
The Northern Shrike hunts from exposed perches. Once a prey is detected, the bird darts out with rapid, powerful flight. It usually uses mainly the hooked bill to kill the prey. However, when small birds are attacked in flight, the shrike may use its feet to force them to the ground.
Then, the dead prey are typically impaled on thorny twig of barbed-wires, and eaten later. The bird may also wedge the prey into a tree fork.
The shrike sometimes feeds on the ground by hopping on rough terrain or brush.
At the beginning of the breeding season, the male sings near potential nesting sites. It brings nest material to its preferred sites to indicate them to a female. Then, the female selects one of the sites and performs most of nest-building, helped by the male that brings nest materials. It also defends the nesting territory by giving its complex song and mimicries of other birds. Both parents share the nesting duties. They are monogamous and strongly territorial.
Most populations are probably migratory and move southwards after breeding. They move south rather late in autumn and return to their breeding areas in early spring.
The Northern Shrike has swift, undulating flight on shallow, rapid wingbeats.
REPRODUCTION OF THIS SPECIES:
The laying occurs in May/June in Alaska and Canada. This species produces a single brood per year, but a replacement clutch is usually laid following nest failure.
The female, helped by the male, builds the nest in low tree or large shrub, often spruce or willow, between 80 cm/2 metres and 3,3/4,5 metres above the ground, depending on the tree species.
The nest is a loose, bulky, open cup made of twigs, grass, bark strips and moss. The cup is lined with feathers and animal hair. It is usually very deep for a bird of this size. When the female is incubating, only her tail tip is visible.
The female lays 4-9 pale grey or greenish-white eggs with brown, olive and grey spots. She incubates (probably alone) during 15-17 days. At hatching, the chicks are helpless and with little down. They are fed by both parents. They leave the nest 19-20 days after hatching, but they still depend on adults for several weeks more.
