The Loggerhead shrike, belonging to genus Lanius, is a passerine bird. It is related to Northern shrike. It is often referred to as Butcherbird because of its carnivorous tendencies. As per Partners in Flight, their present worldwide breeding population is about 5.8 million.
Species: L. ludovicianus
The scientific name for Loggerhead shrike is Lanius ludovicianus.
It has seven recognized subspecies. They are –
Adult Loggerhead shrikes are around 23 centimeters in length (from bill to tail), and they weigh between 45 to 58 grams.
Their wingspan is around 33 centimeters. Their head and back have bluish-gray plumage. Their underparts are white, and rumps are either white or pale gray. They possess black wings along with a unique white colored patch on its primaries. They have a black thin strip that starts from its bill and goes across its eyes and ends a little far from it. They have a short black colored bill that is hooked in front. They possess a black tail with white edges. It has a brown iris. Their tarsus and feet are black. Young bird possess pale gray plumage.
They primarily inhabit open countryside with short trees, well-spaced shrubs, and short vegetation. They are commonly seen in pastures, desert scrublands, savannas, old orchards, agricultural fields, golf courses, gardens, riparian areas, and prairies.
They are native to North America. They are found in central Canada, southern states of Canada and the greater mid-west of US. However, during their migration during summer/spring, they often go as far as California.
They keep up their territories by displays and songs. Intruders are most challenged with intensified prey-stalking displays. They look out for potential preys from tree branches and then diving onto it. At times, they also hunt from the ground by surprising their prey from a hideout. To kill bigger preys, they impale them on throned or sharp objects. Observers have noted this species to have killed animals that are as big as its own size. They transport big preys on its feet and little animals in its bill. Before the start of the breeding season, neighboring individuals often come together and display or call for several minutes. This helps them to peacefully set up breeding territories, and also help new pairs form their own territories near already existing territories. Courtship displays include males singing to females, perform flight displays and also engage in a ritual dance. This bird is primarily monogamous. However, females occasionally raise a second brood with another male in a single season. Newly hatched juveniles are known to perform misdirected, theatrical versions of hunting behaviors of adults. They fly about with sticks, leaves on its bills; and engage in mock aerial chases with no targets.
Both male and female select the nesting site. They make their nest (usually around 2.5 – 4 feet from the ground) in shrubs or trees with dense branches. The nest, which looks like a bulky cup, is made with weeds, twigs, and grass among others. It is lined with soft materials like feathers, animal hairs, or rootlets. Female lay a clutch of 4 – 6 light gray or dull white spotted eggs, in mid-April or late June. Incubation is done by the female only, and this process lasts for 13 to 17 days. During this time, the male provides food to the female. After hatching, both parents feed the nestlings. The juveniles stay dependent on their parents for food for one to four weeks after hatching.
They feed on invertebrates during warm seasons. During nesting season, their primary foods include rodents, grasshoppers and beetles. During winter, their diet include small songbirds, shrews, mice, voles, squirrels and frogs among others.
Their estimated lifespan is 7 or 8 years in the wild. The longest known lifespan of an individual was believed to be 11 years and 9 months. It was a male in California; and it was released by ornithologists, in 2010.
They produce varied jarring and harsh calls. Their notes include guttural warbles, shrill trills, and squeaky whistles. Males are a lot more vocal than females. During breeding season, males mostly produce trills in different pitch and rhythm. Their alarm call sounds like “schgra-a-a.” Males’ territorial call is a harsh shriek; while females’ call is a bit softer and lower pitched. Female may produce ‘mak’ notes when asking for food from the male during breeding season. Nestlings make ‘tsp’ or ‘cheek’ sound following hatching.
Since the 1960s, their population has gone down in North America. Human disturbance, climate change, pesticide contamination and loss of habitat are the primary causes for their fall in numbers.
The IUCN Red List of Threatened Species has kept Loggerhead shrike in the ‘Near Threatened’ category.
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