Pacific Wren
Encyclopedia
The Pacific Wren is a very small North America
n bird
and a member of the mainly New World
wren
family Troglodytidae. It was once lumped with Troglodytes hiemalis of eastern North America and Troglodytes troglodytes of Eurasia
as the Winter Wren.
It breeds along the Pacific coast from Alaska
to California
and inland as far as Wyoming
and the Black Hills
of South Dakota
. It migrates through and winters across the western half of the United States
and Canada
.
The scientific name is taken from the Greek
word "troglodytes" (from "trogle" a hole, and "dyein" to creep), meaning "cave-dweller", and refers to its habit of disappearing into cavities or crevices whilst hunting arthropod
s or to roost.
of individuals in an overlap zone between Troglodytes hiemalis and Troglodytes pacificus, Toews and Irwin (2008) found strong evidence of reproductive isolation
between the two. It was suggested that the pacificus subspecies be promoted to the species level designation of Troglodytes pacificus with the common name of ‘Pacific Wren’. By applying a molecular clock
to the amount of mitochondrial DNA
sequence divergence between the two, it was estimated that Troglodytes pacificus and Troglodytes troglodytes last shared a common ancestor approximately 4.3 million years ago, long before the glacial cycles of the Pleistocene
, thought to have promoted speciation
in many avian systems inhabiting the boreal forest of North America.
and fir
, where it is often identified by its long and exuberant song. Although it is an insectivore
, it can remain in moderately cold and even snowy climates by foraging for insects on substrates such as bark and fallen logs.
Its movements as it creeps or climbs are incessant rather than rapid; its short flights swift and direct but not sustained, its tiny round wings whirring as it flies from bush to bush.
At night, usually in winter, it often roosts, true to its scientific name, in dark retreats, snug holes and even old nests. In hard weather it may do so in parties, either consisting of the family or of many individuals gathered together for warmth.
For the most part insect
s and spider
s are its food, but in winter large pupae are taken and some seeds.
The normal round nest of grass
, moss
, lichen
s or leaves is tucked into a hole in a wall, tree trunk, crack in a rock or corner of a building, but it is often built in bushes, overhanging boughs or the litter which accumulates in branches washed by floods.
Five to eight white or slightly speckled egg
s are laid in April, and second broods are reared.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
and a member of the mainly New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
wren
Wren
The wrens are passerine birds in the mainly New World family Troglodytidae. There are approximately 80 species of true wrens in approximately 20 genera....
family Troglodytidae. It was once lumped with Troglodytes hiemalis of eastern North America and Troglodytes troglodytes of Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
as the Winter Wren.
It breeds along the Pacific coast from Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and inland as far as Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
and the Black Hills
Black Hills
The Black Hills are a small, isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, USA. Set off from the main body of the Rocky Mountains, the region is something of a geological anomaly—accurately described as an "island of...
of South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
. It migrates through and winters across the western half of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
.
The scientific name is taken from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
word "troglodytes" (from "trogle" a hole, and "dyein" to creep), meaning "cave-dweller", and refers to its habit of disappearing into cavities or crevices whilst hunting arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s or to roost.
Description
Rufous brown above, richly colored below, barred with darker brown and dusky, even on wings and tail. The bill is dark brown, the legs pale brown. Young birds are less distinctly barred.Taxonomy
By studying the songs and geneticsGenetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
of individuals in an overlap zone between Troglodytes hiemalis and Troglodytes pacificus, Toews and Irwin (2008) found strong evidence of reproductive isolation
Reproductive isolation
The mechanisms of reproductive isolation or hybridization barriers are a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not...
between the two. It was suggested that the pacificus subspecies be promoted to the species level designation of Troglodytes pacificus with the common name of ‘Pacific Wren’. By applying a molecular clock
Molecular clock
The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...
to the amount of mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
sequence divergence between the two, it was estimated that Troglodytes pacificus and Troglodytes troglodytes last shared a common ancestor approximately 4.3 million years ago, long before the glacial cycles of the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, thought to have promoted speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
in many avian systems inhabiting the boreal forest of North America.
Ecology
The Pacific Wren nests mostly in coniferous forests, especially those of spruceSpruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
and fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
, where it is often identified by its long and exuberant song. Although it is an insectivore
Insectivore
An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....
, it can remain in moderately cold and even snowy climates by foraging for insects on substrates such as bark and fallen logs.
Its movements as it creeps or climbs are incessant rather than rapid; its short flights swift and direct but not sustained, its tiny round wings whirring as it flies from bush to bush.
At night, usually in winter, it often roosts, true to its scientific name, in dark retreats, snug holes and even old nests. In hard weather it may do so in parties, either consisting of the family or of many individuals gathered together for warmth.
For the most part insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s are its food, but in winter large pupae are taken and some seeds.
Breeding
The male builds a small number of nests. These are called "cock nests" but are never lined until the female chooses one to use.The normal round nest of grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
, moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
, lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
s or leaves is tucked into a hole in a wall, tree trunk, crack in a rock or corner of a building, but it is often built in bushes, overhanging boughs or the litter which accumulates in branches washed by floods.
Five to eight white or slightly speckled egg
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
s are laid in April, and second broods are reared.