Lanius ludovicianus Linnaeus, 1766, Louisiana. Up to 12 races described; some of them poorly differentiated. Variation affects size and plumage coloration, particularly of the back and underparts.
OTHER COMMON NAMES
English: Migrant shrike; French: Pie-griиche migratrice; German: Louisianawьrger; Spanish: Alcaudon Yanqui.
About 8.2 in (21 cm); on average 1.7 oz (48 g). The loggerhead is relatively large, large-headed, gray, black, and white shrike; sexes are similar or nearly so. Facial mask extends just over the eyes. Upperparts are gray with white scapulars. Wings and tail are mainly black, but with a white primary patch and white outer tail feathers. Underparts are white, sometimes with faint indications of barring. Juveniles are similar, but paler, brownish gray, and barred overall. Nominate, common in southeastern United States, is dark gray above, including on rump, and almost pure white below, whereas excubitorides from the Great Plains region of the west is a pale race with a white rump. The endangered race mearnsi, confined to the San Clemente Island of California, is a darker gray than any other subspecies on it upperparts. The loggerhead shrike resembles the northern shrike, but the latter is about 25% larger, paler gray above, and with a facial mask not extending over the eyes, and particularly narrowed in lores.
Only endemic shrike in North America, from southern Canada to Mexico. Northern part of breeding range is vacated in winter; contacts then possible with the relatively similar northern shrike, which also migrates further south from its breeding grounds in Alaska and northern Canada.
Various types of semi-open habitats with short vegetation; pastures are favored in many areas in Missouri, Illinois, and New York. In the western part of its range, it also occurs in semiarid sagebrush areas, desert scrub, and pinyon-juniper woodlands; may occur in residential areas that are well dotted with perches. May be present in mountainous areas up to about 6,600 ft (2,000 m).
Usually solitary or in pairs, but curious group meetings have been reported. Size of territory varies with habitat quality and averages about 25 acres (10 ha), but appears to be three times as large in the rare San Clemente race. Territory is defended with loud song and harsh territorial calls that may be produced in flight. It hunts from an elevated perch (6.6–33 ft [2–10 m]) and catches most of its prey on the ground. Impaling is regular; prey weighing more than about 1.1 oz (30 g) may be carried in the feet. Populations nesting north of about 40°N migrate and may move into areas with resident birds; most leave between September and November and return in March or April. In some southern areas, pairs maintain territories throughout the year; but in others, they separate and often defend adjacent territories.
FEEDING ECOLOGY AND DIET
All kinds of arthropods, mainly insects, most commonly beetles and grasshoppers. Vertebrate prey is regularly taken, particularly in winter; it includes small birds, lizards, mice, and occasionally bats and fish.
Territorial and normally monogamous. Even in well-populated areas, nests are normally several hundred yards (meters) apart, but small colonies have been reported occasionally. Northern populations are single-brooded, whereas second broods are common and third broods occasional in southern areas, such as Florida. Replacement clutches are frequent everywhere. Female usually lays four or five eggs (ranges one through seven); clutch size seems to vary with latitude. Female alone incubates for about 16 days; she is fed in the nest by the male. Nestling period is 16–21 days according to weather conditions. The young are independent four to five weeks after fledging, but they may stay up to three months with the parents.
Not threatened yet, but populations have experienced a marked decline in many regions, particularly in the northern part of the range. It is classified as endangered in Quebec. The highly endangered San Clemente race benefits from strong conservation measures; these measures include eradication of predators, removal of herbivores that tend to destroy the habitat, and breeding in captivity in the San Diego Zoo for reinforcement operations.
SIGNIFICANCE TO HUMANS
Of high significance to North American conservationists, as it is declining dramatically in most parts of range.
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