Federally Listed Endangered, Threatened, and Candidate Species 1995
Loggerhead Shrike (Lanius ludovicianus)
Status:Former Candidate(Note: As of February 28, 1996, this species is no longer listed as a Candidate species. However, it remains a species of management concern.)
Historical Status:
Historically present in most of
North America except the far north.
Present Status:
Found throughout most of the United
States and Mexico and south-central Canada although it seems to be declining in most areas. Winters in southern United States and Mexico. Fairly common throughout North Dakota except in the Red River Valley.
Habitat:
The loggerhead shrike prefers open country with patches of trees or shrubs present. Wooded coulees and shelterbelts with native prairie or cropland nearby are common habitat types in North Dakota. Orchards and cherry thickets are also frequently used.
Life History:
Loggerhead shrikes are solitary
throughout the year except for the breeding season. Courtship consists of the male feeding the female and flying back and forth in front of her from a distance of about 20 feet. The peak of the breeding season is from early May to mid-July. Nests are made of twigs, barks, and other materials. They are usually in isolated small trees, about 10 feet above the ground. The average number of eggs per nest appears to be about 5. The male feeds the female while she is incubating. Incubation lasts about 16 days. Young can leave the nest about 20 days after hatching and are independent of the parents about 36 days after hatching. Adult shrikes can produce two broods annually. Loggerhead shrikes often hunt from low perches like fenceposts where they pounce on their prey and then quickly return to the perch. Since shrikes don't have talons they kill with a stunning blow from their beaks. Studies have indicated that the majority of the loggerhead shrikes diet consist of
insects in the summer (approximately 83 percent) and mice in the winter. Shrikes have the unique habit of impaling their prey on thorns or barb-wired fences. They usually return to feed on the impaled prey at a later date.
Aid to identification:
The loggerhead shrike is
slightly smaller than a robin, averaging about 9 inches in length. The head and back is a bluish-gray color, the underparts white, and the top of the tail and wings is black. The loggerhead shrike also has a very characteristic black mask across the face. Juveniles are predominately a pale brown-gray color. The song is a medley of low warbles and harsh notes. The loggerhead shrike is similar in appearance to its more northern cousin the northern shrike. The northern shrike is larger (about 10 inches long) and has a more hooked bill. The black face mask in the northern shrike does not extend above the eye. Ranges of the two shrikes may overlap in the winter time across the central and northern United States.
Reasons for decline:
Habitat loss is a major reason
for the decline. Pesticides are a problem, especially in the central United States and southern Canada. Shrikes are susceptible to automobiles because of their habit of feeding on grasshoppers and other insects.
Comments:
The name loggerhead comes from the fact
that the birds head is disproportionately larger than the rest ot the body. The name "shrike" comes from the word "shriek" in reference to the shrill call the bird makes. Shrikes are also known as "butcher birds" because of their habit of impaling their prey on sharp objects. A sign of the presence of shrikes are the remains of prey impaled on barb-wired fences and thorns. Shrikes are considered the only truly predatory songbirds because they consistently feed on small animals. The San Clemente subspecies of the loggerhead shrike is listed as endangered.
References:
Breeding Birds of North Dakota by R.
Stewart, 1975.