Habitat: The shrike prefers grassy pastures that provide sparse cover for prey, contain shrubs or small trees for nesting and anchoring prey, and have high perches for surveying territory.
Summer Range: The Loggerhead shrike summers and breeds in southern Alberta, Saskatchewan, and Manitoba, southward to Florida and southern Mexico. Their spring migration occurs throughout March, April and early May. They appear to travel individually and mainly at night.
Winter Range: The Loggerhead shrike’s wintering grounds range from southern Oregon, southern Kansas, Tennessee, Virginia, and southward to southern and coastal Mexico. In the fall, these shrikes migrate between September and November.
Food: The loggerhead shrike eats insects, amphibians, lizards and other small reptiles, mice and other small mammals, and birds. Grasshoppers and beetles are their main food sources during the breeding season. When insects are harder to find, shrikes will consume larger prey.
The loggerhead shrike perches while scanning for food. The hook at the end of its beak helps it sever the spinal cord of its prey. The shrike impales its prey on thorns or barbed wire, or wedges the prey into a fork in a branch to hold them while it rips them up.
Breeding Behaviour: During the spring courtship, both male and female loggerhead shrikes make a range of noises. They are songbirds, but their calls are unmusical and when alarmed, the birds emit a variety of shrieks. Loggerhead shrikes return to Canada to breed and begin to breed when they are a year old. Loggerhead shrikes are mainly monogamous, although after the young have left the nest, females may desert males to raise a second brood with another male.
Nest Type and Egg Description: Both males and females help to find the nest site and gather materials. The female builds the 15-20 cm diameter nest alone in about six to 11 days. It is made of thickly woven dead plant material that provides good insulation against the cold weather in early spring. The nest is generally in dense cover a couple of metres off the ground, although it may be built several metres above ground.
The loggerhead shrike produces five or six grayish buff eggs with dark spots around the large end. Egg laying begins in the east in late April and mid- to late May in the west. The clutch size ranges from one to nine.
Incubation of the eggs begins when she has almost finished laying. The young are born helpless, blind, and have little down. A chick grows to nearly full size in just two weeks (from 3 g at hatching to 45 g after two weeks). The young leave the nest when they are 17 to 20 days old, but return at night to be warmed by their mother who continues to be fed them for two to three weeks after they have fledged (left the nest).
Conservation Status: The Loggerhead shrike was once abundant, but the last half of 20th century saw a huge decline. They are now primarily found in the northeastern part of their traditional range, and a continued decline throughout the range is observed.
In the United States, only the subspecies of loggerhead shrike on San Clemente Island, California, is listed as “endangered”. The breeding populations of the two subspecies found in Canada, where the loggerhead shrike is designated a species at risk, have been in a gradual decline for the past 100 years.
Scientists do not know why its numbers continue to decline. In Canada, the Eastern loggerhead shrike faces extirpation. It has already disappeared from New Brunswick and Quebec. Only a few dozen breeding pairs, in five widely separated locations, are found in Ontario, and only about a dozen breeding pairs have been identified in southeastern Manitoba.
The Prairie loggerhead shrike is more abundant, although its numbers are also declining. The Committee on the Status of Endangered Wildlife in Canada has assessed the Eastern Loggerhead shrike as endangered and the Prairie loggerhead shrike as threatened.
Under the federal Species at Risk Act (SARA) the Eastern loggerhead shrike is “protected,” but the Prairie loggerhead shrike is undergoing consultations to determine if it should be listed under SARA.
Information on this page compiled by Colleen Sutton.
BirdLife International. http://www.birdlife.org
Committee on the Status of Endangered Wildlife in Canada. http://www.cosewic.gc.ca/eng/sct5/index_e.cfm
Cornell Lab of Ornithology. All About Birds. http://www.birds.cornell.edu/AllAboutBirds/.
Ehrlich, Paul R. 1988. The Birder’s Handbook. Simon and Schuster, New York.
Godfrey, Earl W. 1986. Birds of Canada. National Museums of Canada, Ottawa.
Hinterland Who’s Who. http://www.hww.ca
Leslie, Scott. 2006. Wetland Birds of North America. Key Porter Books, Toronto. NatureServe. InfoNatura. http://www.natureserve.org/infonatura/