Loggerhead Shrike Life History

Habitat

Habitat Open WoodlandsLoggerhead Shrikes inhabit open country with short vegetation and well-spaced shrubs or low trees, particularly those with spines or thorns. They frequent agricultural fields, pastures, old orchards, riparian areas, desert scrublands, savannas, prairies, golf courses, and cemeteries. Loggerhead Shrikes are often seen along mowed roadsides with access to fence lines and utility poles. Back to top

Food

Food InsectsLoggerhead Shrikes eat insects and other arthropods, amphibians, reptiles, small mammals, and birds; they also sometimes feed on roadkill and carrion. Their staple foods include agricultural pests such as grasshoppers, beetles and rodents. Insects generally dominate the Loggerhead Shrike’s diet during breeding season, while winter brings a greater reliance on vertebrate prey. These include lizards, snakes, frogs, turtles, sparrows, goldfinches, ground squirrels, voles, mice, and shrews, to name just a few.Back to top

Nesting

Nest Placement

Nest TreeBoth sexes help find the nest site, inspecting many locations before choosing. Loggerhead Shrikes often build their nests in thorny vegetation, which may help keep predators away. In the absence of trees or shrubs, they sometimes nest in brush piles or tumbleweeds. Average height of nests above the ground ranges from about 2.5–4 feet.

Nest Description

Both sexes gather material. The female usually constructs the nest on her own, over a period of about 6–11 days. The bulky, well-insulated open cup is neatly woven of rootlets, twigs, forbs, and bark strips and lined inside with soft material such as flowers, lichen, grass, moss, feathers, fur, string, or cloth. The nest is about 6 inches in diameter on the outside, with an interior diameter of about 4 inches; the cup is about 3 inches deep.

Nesting Facts
Clutch Size:5-6 eggs
Number of Broods:1-2 broods
Egg Length:0.9-1.1 in (2.3-2.7 cm)
Egg Width:0.7-0.8 in (1.8-2 cm)
Incubation Period:15-17 days
Nestling Period:16-20 days
Egg Description:Eggs are grayish buff, marked with gray to yellowish-brown.
Condition at Hatching:Naked, blind, and helpless, with closed eyes.
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Behavior

Behavior Aerial Dive (ground/talons)Loggerhead Shrikes hunt by scanning the ground from elevated perches, then diving onto prey. They also hover-hunt. Loggerhead Shrikes sometimes hunt from the ground, flashing their wing patches in a manner similar to the Northern Mockingbird, to startle prey out of hiding. To immobilize large prey items, the Loggerhead Shrike impales them on sharp objects such as thorns and barbed wire, or tucks them into forks between branches. Caches of prey thus lain away, also called “larders” or “pantries,” provide food stores during winter when prey is scarce, or in breeding season when energy demands are high. A well-provisioned larder may also help a male shrike attract a mate. Loggerhead Shrikes maintain territories largely through songs and displays. Males challenge intruders with a wing-fluttering bow, like an intensified version of their prey-stalking display. Displaying rivals usually face away from one another, but may whirl to face each other or stamp the ground. Before nesting, several neighboring shrikes may gather together and call or display for several minutes. This may help establish territories in the neighborhood, promote pair formation, and help new arrivals find territories near already-established birds. Courting males feed and sing to females, perform a ritual dance, and/or perform a flight display. They are mostly monogamous, although females occasionally raise one brood with one male and then take up with another mate for a second brood the same season.Back to top

Conservation

Conservation Common Bird in Steep DeclineLoggerhead Shrikes are still fairly numerous in some areas (particularly the South and West), but their populations have fallen sharply. Between 1966 and 2015, the species declined by almost 3% per year, resulting in a cumulative decline of 76%, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population is 5.8 million, with 82% spending some part of the year in the U.S., 30% in Mexico, and 3% breeding in Canada. The species rates an 11 out of 20 on the Continental Concern Score, and the 2014 State of the Birds Report lists them as a Common Bird in Steep Decline. Loggerhead Shrikes have been listed as endangered, threatened, or of special concern in several states and Canada, and have been proposed for federal listing (the subspecies that nests on San Clemente Island, California, is listed as endangered). The species’ decline coincides with the introduction and increased use of chemical pesticides between the 1940s and the 1970s, and may result in part from the birds’ ingestion of pesticide-laced prey from treated fields. Other likely causes of population decline include collision with vehicles, urban development, conversion of hayfields and pastureland, decimation of hedgerows, habitat destruction by surface-coal strip-mining, and altering of prey populations by livestock grazing. Given this bird’s potentially high reproductive rate, and provided that adequate habitat continues to be available, Loggerhead Shrike populations may be able to recover if the causes of the bird’s decline can be identified and eliminated.Back to top

Credits

Dunne, Pete. 2006. Pete Dunne's essential field guide companion: Houghton Mifflin Harcourt.

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.

Partners in Flight. 2017. Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, Jr. Ziolkowski, D. J., K. L. Pardieck, J. E. Fallon and W. A. Link. The North American breeding bird survey, results and analysis 1966-2015 (Version 2.07.2017). USGS Patuxent Wildlife Research Center 2017.

Sibley, David Allen. 2014. The Sibley guide to birds, second edition. Alfred A Knopf, New York.

Yosef, Reuven. 1996. Loggerhead Shrike (Lanius ludovicianus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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