Crissal Thrasher
Encyclopedia
The Crissal Thrasher is a large thrasher
Thrasher
Thrashers are a New World group of passerine birds related to mockingbirds and New World catbirds. Like these, they are in the Mimidae family. There are 15 species in one large and 4 monotypic genera.These do not form a clade but are a phenetic assemblage...

 found in the Southwestern United States
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...

 (western Texas, southern New Mexico, southern Arizona, southeastern California, extreme southern Nevada, and extreme southwestern Utah) to central Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

.

Description

The bird grows to 32 cm (12.5 inches), and has a deeply curved bill. The eyes are dull yellow. Bird expert Roger Tory Peterson
Roger Tory Peterson
Roger Tory Peterson , was an American naturalist, ornithologist, artist, and educator, and held to be one of the founding inspirations for the 20th century environmental movement.-Background:...

 described its singing as sweeter and less spasmodic than other thrashers. It can be found near desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...

 streams
STREAMS
In computer networking, STREAMS is the native framework in Unix System V for implementing character devices.STREAMS was designed as a modular architecture for implementing full-duplex I/O between kernel or user space processes and device drivers. Its most frequent uses have been in developing...

 in dense underbrush, mesquite
Mesquite
Mesquite is a leguminous plant of the Prosopis genus found in northern Mexico through the Sonoran Desert and Chihuahuan Deserts, and up into the Southwestern United States as far north as southern Kansas, west to the Colorado Desert in California,and east to the eastern fifth of Texas, where...

 thickets, willows, scrub oak
Scrub Oak
Scrub Oak is a general name for several species of small, shrubby oaks, including the following species:*California Scrub Oak *Leather Oak *Coastal Scrub Oak...

, high elevations in manzanita
Manzanita
Manzanita is a common name for many species of the genus Arctostaphylos. They are evergreen shrubs or small trees present in the chaparral biome of western North America, where they occur from southern British Columbia, Washington to California, Arizona and New Mexico in the United States, and...

, and in the low desert near canyon chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...

. The bird seldom flies in the open. The Crissal Thrasher rarely flies, preferring to walk or run around its territory and will mostly run for cover when disturbed by a potential predator.

History

In the early years of the study of the birds of western North America, this species was confused with the California Thrasher
California Thrasher
The California Thrasher is a large thrasher found primarily in chaparral habitat in California and Baja California. Similar to the Crissal and Le Conte's Thrashers in habit, the California Thrasher is the only species of Toxostoma throughout most of its limited range...

 (Toxostoma redivivum), to which it is closely related. Descriptions of T. redivivum in John Cassin
John Cassin
John Cassin was an American ornithologist.He is considered to be one of the giants of American ornithology, and was America's first taxonomist, describing 198 birds not previously mentioned by Alexander Wilson and John James Audubon...

's 1856 book Illustrations of the Birds of California, Texas, Oregon, British, and Russian America led later ornithologists to conclude that at least three of the birds described were actually the Crissal Thrasher. When an army surgeon working in New Mexico sent Cassin specimens of a bird that he believed to be the California Thrasher, Cassin sent the specimens to Spencer Baird at the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

. Baird determined that it was not a California Thrasher and published his findings in 1858, identifying the Crissal Thrasher as a new species.

Printer's errors in Baird's 1858 publication led to longstanding confusion and contention over the naming of the Crissal Thrasher. As printed, Baird's publication identified the new species as Toxostoma dorsalis, because the printer had switched the species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 name of the new thrasher with the species name of a new junco
Junco
A Junco , genus Junco, is a small North American bird. Junco systematics are still confusing after decades of research, with various authors accepting between three and twelve species...

 species, Junco dorsalis. Baird arranged for the error to be corrected, recording the name as T. crissalis the following month. Thereafter, the T. crissalis name was accepted and used until 1920, when ornithologist Harry Oberholser published a note asserting that T. dorsalis must be used instead because it had publication priority over T. crissalis, even though the original publication had been a mistake and had been quickly corrected. As a result, the T. dorsalis epithet appeared in ornithological literature until 1983, when the International Commission on Zoological Nomenclature
International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 28 members from 20 countries, mainly practicing zoological taxonomists...

 formally restored Baird's intended name of T. crissale.

Nest

The Crissal Thrasher builds its nests in dense shrubs about 3 to 8 feet up, typically under a large branch for protection both from other birds and the sun. The male and female cooperate in building the cup-shaped nest, which is built from twigs and lined with finer vegetation. The eggs, which are blue in color and lack spots (this is the only species of thrasher to lay eggs without spots), are laid in clutches of 2 to 3 eggs and incubate
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...

d for about 2 weeks, with both the male and female taking turns on the nest. The young are fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...

d 11 to 13 days after they hatch. The chick is paler and duller than the adult, with a browner undertail.

Diet

The species is an omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...

, eating both insects and spiders, and seeds and fruits. The Crissal Thrasher is mainly a ground feeder, using its long bill to probe for its prey amongst the leaf litter, particularly under shrubs.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK