Lanius ludovicianusloggerhead shrike

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Geographic Range

Prominent in many parts of central Canada, border states of Canada, and in the Greater Midwest of the United States. During its spring / summer migration, however, it can sometimes be seen as far south and west as California though in ever decreasing numbers. For example, its predicted range of migration to and from the state of Indiana is: Arrival from March 15 to 25, and Return from about November 1 to 15.

There are some exceptions to the Shrike's migration, such as its noted presence in the well-suited Florida environment. Thus, habitat and environment are more important in determining migratory patterns for this species than the standard geographic range, especially as suitable hunting grounds become increasingly scarce.

Habitat

Except when nesting, both sexes of the species will prefer to spend most of their time in open places hiding in order to search for prey and surprise it. Thus, the Loggerhead will prefer a country field bordered with trees or replete with brush / thickets to almost any other.

Physical Description

This shrike is a medium-sized passerine. As with many song birds, the Loggerhead Shrike has several different colors whose arrangement is considered important in attracting a mate (along with displayed hunting prowess). The shrike's greyish back and black wings are evident against its white breast and other body areas. Most prominent, however, is the Loggerhead's black mask which extends around the eyes and down into the forehead. This shrike also has a slightly hooked beak somewhat similar to that of a falcon's beak which is used for impaling its prey, though unlike many birds of prey lacks talong or claws.

It is eight to ten inches long and has a wing span of approximately 12 inches, making it about the size of an average robin.

The male and female of the species are similar in appearance.

  • Average mass
    46 g
    1.62 oz
    AnAge

Reproduction

During its April to July breeding season, the male Loggerhead will often kill prey it does not otherwise need in order to display its power. This will hopefully attract a female who seeks a dominant male who is capable of providing food for itself and the offspring.

As for the offspring themselves, nests for eggs are always built in trees, usually about 8 to 15 feet above the ground. The nests are cup-shaped, and house approximately four to seven dull white to light grey spotted eggs.

  • Average eggs per season
    5
    AnAge
  • Average time to hatching
    11 days
    AnAge

Lifespan/Longevity

Behavior

The behavior of the Loggerhead, including mating patters, is based almost entirely around hunting as mentioned in other sections. The need to hunt for hunger, for offspring, or for attraction of the opposite sex for procreation is the dominant factor in its existence.

Communication and Perception

Food Habits

Loggerhead shrikes are the only known predatory songbird. They prey on both vertebrate and invertebrate animals, but due to their lack of talons or claws they must impale their prey. Impaling is done with the slightly hooked beak, often against either a tree or into barbed wire. While its diet consists mostly of mice, it will also eat insects, small amphibians, and even small birds.

Economic Importance for Humans: Positive

May eat potentially harmful insects.

Economic Importance for Humans: Negative

Though not directly having much of an effect either negatively or positively, the fact that the Loggerhead is an endangered species with very specific hunting patterns means that any area in which a Loggerhead is found to reside is instantly zoned for its protection, even if it is a residential area. Such a zoning occured in 1993 in a suburb of Los Angeles.

Conservation Status

Overall, loggerhead shrikes have a large population size and a large range. One subspecies, the San Clemente loggerhead shrike (Lanius ludovicianus mearnsi) is listed as endangered by the U.S. Fish and Wildlife Service. Also, migrant loggerhead shrikes (Lanius ludovicianus migrans) are listed as endangered in the state of Michigan. Loggerhead shrikes are protected by the U.S. Migratory Bird Act.

Contributors

Christopher Porter (author), Cocoa Beach High School, Penny Mcdonald (editor), Cocoa Beach High School.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Greatplains.org, 2000. "Songbirds of North Dakota" (On-line). Accessed 1-31-2000 at http://www.greatplains.org/npresource/distr/BIRDS/SONGBIRD/LANIIDAE.HTM.

Kopczynski, A. November 18, 1998. "BIRDS OF INDIANA: Family Lanidae. Shrikes." (On-line). Accessed 2-1-2000 at http://www-lib.iupui.edu/butlerbirds/order15_09.html.

McGill University, A. 1999. "Loggerhead Shrike (Lanius ludovicianus)" (On-line). Accessed 1-31-2000 at http://www.nrs.mcgill.ca/ascc/conservation/shrike1.htm.