Loggerhead shrike

In 1760 the French zoologist Mathurin Jacques Brisson included a description of the loggerhead shrike in his Ornithologie based on a specimen collected in Louisiana in the United States. He used the French name La pie-griesche de la Louisiane and the Latin Lanius ludovicianus. Although Brisson coined Latin names, these do not usually conform to the binomial system and are not recognised by the International Commission on Zoological Nomenclature. When in 1766 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the twelfth edition, he added 240 species that had been previously described by Brisson. The specific name ludovic is Late Latin for "Louis" and the epithet "-ianus" is to describe something being of another or possessed by it. When translated, its scientific name means something alongside the lines of "Louis' butcher". "Loggerhead," a similar word to "blockhead," refers to the unusually large head to body ratio of this bird. There are seven recognized subspecies: • L. l. excubitorides Swainson, 1832 – central Canada, central and west USA • L. l. migrans Palmer, W, 1898 – east North America • L. l. ludovicianus Linnaeus, 1766 – coastal southeast USA • L. l. anthonyi Mearns, 1898 – Channel Islands (off south California, southwest USA) • L. l. mearnsi Ridgway, 1903 – San Clemente Island (off south California, southwest USA) • L. l. grinnelli Oberholser, 1919 – extreme south California and north Baja California (northwest Mexico) • L. l. mexicanus Brehm, CL, 1854 – west and central Mexico, south Baja California (northwest Mexico) Miller, in 1931, suggested that the wing-chord-to-tail-length ratio was an important indicator for distinguishing between subspecies. ==Description==

The loggerhead shrike is a medium-sized passerine. "Loggerhead" refers to the relatively large size of the head as compared to the rest of the body. The wing and tail length are about and long, respectively. ;Measurement ranges • Length: • Weight: • Wingspan: The adult plumage of the loggerhead shrike is grey above with a white to pale grey breast and black tarsi and feet. The bird possesses a black mask that extends across the eyes to its bill. The wings are black with a distinct white patch on the primaries. The tail is black edged with white and the irises are brown. The beak is short, black, and hooked, and contains a tomial tooth to help tear into prey. It is difficult to sex an adult loggerhead shrike in the field as they are sexually monochromatic. However, several studies have reported sexual dimorphism in plumage and size traits. Juveniles possess a paler gray plumage that is subtly vermiculated. The loggerhead shrike can be distinguished from the northern shrike by its smaller size, darker grey plumage, and larger black face mask that covers the eye completely. It also has a shorter bill with less prominent hook. Their calls are similar. The shrike's notes include squeaky whistles, shrill trills, and guttural warbles. During courtship feedings, females may ask for food with "mak" begging notes; conversely, males emit "wuut" or "shack" sounds to offer food. The male emits a territorial, harsh shriek, while the female's song is pitched lower and softer than the male's. Generally, the male is far more vocal than the female. ==Distribution and habitat==

Loggerhead shrikes were once widely distributed across southern Canada, the contiguous USA and Mexico. L. l. mearnsi is only found on San Clemente Island in California, whereas L. l. gambeli breeds on the mainland and L. l. anthonyi breeds on the Channel Islands. The hawthorn's thorns and the cedar's pin-like needles protect and conceal the shrike from predators. It may also nest in fence-rows or hedge-rows near open pastures and requires elevated perches as lookout points for hunting. ==Behavior==

Diet Loggerhead shrikes have been repeatedly observed killing prey larger than themselves by spearing the neck or head of the animal and twisting. The speed at which this occurs causes a whiplash injury to the animal. The neck strength of the shrikes compensates, making their talon weakness inconsequential. Although loggerhead shrikes are passerines, they are a predatory species that hunt during the day. They primarily eat insects, but also consume arachnids, reptiles, amphibians, rodents, bats and small birds. They have even eaten venomous snakes such as the water adder. The size of prey ranges from insects to mice or reptiles. In winter, prey availability is low due to the shrike's preference for insects and poikilothermic prey; during this time, shrikes may be energetically stressed and underweight. Kleptoparasitism has also been observed in nature, in which the shrike chased down another bird and stole its recently caught prey. Reproduction Loggerhead shrikes are monogamous birds. However, males are known to begin second nesting attempts with a second female before his first clutch has fledged. They begin breeding during their first spring. Females may respond to the fluttering display with begging notes, similar to those of juveniles begging for food; this encourages the male to feed her. There is an increase in average clutch size as latitude increases. Shrikes begin incubation after laying the second to last egg, resulting in asynchronous hatching. Incubation, on average, lasts 16 days. The female lays 4 to 8 eggs in a bulky cup made of twigs and grass. Once hatched, nestlings are fed by both the male and female parent. Average fledging period is about 19 days. Young may then remain nearby and dependent on adults for 3 to 4 weeks. After that, they begin to forage independently. Oftentimes, nestlings do not survive long past hatching. In the case of dead nestlings, adult shrikes may eat or discard their bodies or else feed them to their remaining young. The oldest recorded age of a loggerhead shrike was 12 years and 6 months. ==Conservation status==

Loggerhead shrike populations have been decreasing in North America since the 1960s. Reasons behind the decline remain unclear, although suggestions include habitat loss, pesticide contamination, and human disturbance. The San Clemente Island shrike, L. l. mearnsi, is critically endangered, with a population as low as 5–10 individuals during 1983–1988. A captive population was established at the Toronto Zoo and McGill University in 1997. In 2001, an experimental field breeding and release program managed by Wildlife Preservation Canada was established. "Field breeding" refers to moving captive pairs from their wintering cages at the Toronto Zoo and McGill to large enclosures within shrike habitat in Ontario where the pairs nest and raise their young. The young then are released to the wild when they'd naturally disperse from their parents. Since 2004, over 90 young have been released annually and between 2% and 6.5% of young released have successfully migrated and returned to breed in the subsequent year. ==References==