Wrens: Troglodytidae

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WRENS: Troglodytidae

CACTUS WREN (Campylorhynchus brunneicapillus): SPECIES ACCOUNTS
HOUSE WREN (Troglodytes aedon): SPECIES ACCOUNTS
WINTER WREN (Troglodytes troglodytes): SPECIES ACCOUNTS
BLACK-CAPPED DONACOBIUS (Donacobius atricapillus): SPECIES ACCOUNTS

PHYSICAL CHARACTERISTICS

Wrens range in length from 3.5 to 9 inches (9 to 22 centimeters) and weigh between 0.3 and 2 ounces (8 and 57 grams). This songbird of the undergrowth and scrub has feathers that are generally brown or gray-brown. Its wings are short and rounded. They carry their tails in an upright position. Some of them have prominent bars or spotting on the underparts as well as barring on their tails. Both the male and female look alike. They do not have different colors during breeding. Their bills tend to be thin, long, and curved.

GEOGRAPHIC RANGE

Wrens are an American family of birds that can be found throughout North and South America, as far north as Alaska and northern Canada and as far south as Tierra del Fuego in Argentina (the southern tip of South America). One species lives in Europe, North Africa, and Asia. The greatest diversity of species can be found in Central and South America.

HABITAT

The many species and subspecies of wrens live in a large range of habitats depending on their location. They include grasslands, deep forests, forest edges, marshland vegetation such as reeds and cattails, some wetland forests, abandoned farmland, and suburban gardens.

DIET

The eating habits of the majority of wrens remain unknown. The wrens whose eating habits are known—particularly the ten North American species that have been well studied—are primarily carnivores, eating insects. Cactus wrens are one of the known exceptions, eating large quantities of vegetable matter, such as cactus seeds. Other exceptions are the Carolina wren and Bewick's wren, which feed on berries and plant seeds in the winter.

Some species' diets might also include small frogs or lizards. Wrens usually look for food from their perch rather than catching it in midair. Some species gather their food from whatever is scattered over the forest floor. Most of the other species (whose habits have been observed) feed in the bottom areas of tangled vegetation, with some hunting at slightly higher levels. Some tropical species will follow ant swarms, but none do it on a regular basis.

BEHAVIOR AND REPRODUCTION

Wrens are often known to be secretive in their habits, though this characteristic does not include all members of the family. Some species, such as the cactus wrens, are very much the opposite of secretive—they are noisy birds who make their presence known. Still, most wrens do like to live quiet lives and spend their days in the lower levels of dense undergrowth. They disappear when they notice the least noise or activity that is outside of their own. The nightingale wren is a prime example of this sort of disappearance. Because of this, the nightingale wren is also very hard to observe.

The wrens' vocalizations are what make them noticeable. They sing very loudly, usually way out of proportion for their size. Some species sing not simply in spring or summer but throughout the year. Wrens can have as few as three songs to as many as 219, which is the number of songs recorded from the western marsh wren. Vocalization is used as territorial protection and defense during and outside of breeding seasons.

Wrens have three breeding habits that are unique. They build multiple nests, have multiple partners, and have cooperative nesting, meaning other birds help care for the nest of a breeding pair. Egg destruction of both their own and other species' eggs is also common. Observers have suggested that this could be a way of reducing competition for food sources. In fact, the population decline for some wrens, such as Bewick's wren in eastern North America, has been directly linked to the rise of population in the house wren, due probably to its habit of attacking nests.

The nests that wrens build for breeding are sturdier than those built just for roosting. Wrens like to have a quick getaway when disturbances are nearby, and this led observers to believe that the flimsy roosting nests makes that quick getaway easier. Other species, like the cactus wrens, roost in their nests year-round. Most of the nests are domed with side entrances. Some species, like the northern house wren, do not build nests with a roof over them. Also, many other species build beautiful and elaborate nests, sometimes with two chambers. In the case of the song wren, the opposite is true—their nests are very messy.

North American wrens lay three to ten eggs at a time. The eggs are various colors, with some white to cream, tan, or pink, and often having a brownish mottling on them that can be very pale to very bold in color. The female of the smaller species incubates the eggs (warms them for hatching) for twelve to fifteen days; in larger species, the incubation might average up to sixteen days. The young are hatched helpless, blind, and naked, and are fed by both parents until they become fledglings (grow their flight feathers). This occurs when they are ten to seventeen days old in the smaller species, and an average of twenty-one days in the larger. After fledging, the parents continue to feed the young for about two weeks, unless the female begins produce another group of young. In that case it is usually the male that takes the responsibility for feeding. In many of the species, the young continue to return to the breeding nest to roost for an extended period of time. While some species breed at one year of age, others continue to stay with their parents for years and help raise their siblings. This is called cooperative breeding.

WRENS AND PEOPLE

Wrens do not seem to have much of an impact on agriculture or farming. They have been significant to humans throughout the centuries in legend and poetry, and as hunted birds. In Celtic myth, the wren was the king of the oak tree, symbolizing the old year. The robin (part of the thrushes and chats family) was the symbol for the new year. That is suggested as the cause for the practice of some Celtics in the British Isles, including parts of Ireland, to hunt the wren at the end of the year on St. Stephen's Day (December 26) in order to pave the way for the robin's eventual arrival. In Native American culture, the wren symbolizes the "busybody" probably due to its continual singing, and was expected to be present at labor, rejoicing the birth of a girl, and lamenting the birth of a boy.

CONSERVATION STATUS

Most species are in no known danger of extinction (no longer existing). Some populations have actually increased, while others have declined or become separated due to the loss of forests. Human activities and intervention have actually helped in the case of the northern and southern house wrens, birds known for their easy adaptation to suburban gardens and backyards. Some species, however, are in danger. Two species, Apolinar's wren and the zapata wren, are considered Endangered, facing a very high risk of extinction. Niceforo's wren is Critically Endangered, facing an extremely high risk of extinction. Cobb's wren and the clarion wren are Vulnerable, facing a high risk of extinction, and three other wren species are listed as Near Threatened, in danger of becoming threatened with extinction.

CACTUS WREN (Campylorhynchus brunneicapillus): SPECIES ACCOUNTS

Physical characteristics: The cactus wren measures in length from about 7.2 to 8.5 inches (18 to 21.6 centimeters) and is the largest species of wren in North America. In color, the bird is a chocolate brown on top with a plain cap. Its back is streaked very prominently in black and white, and the wings, which can spread to a length of 10.7 inches (over 27 centimeters), are barred with buff and black tones. The tail feathers vary between having blackish brown and gray-brown bars. The outer tail feathers are very noticeably barred black and white. The underparts of the bird are buff-white and are spotted heavily with black, especially on the chest. Eyes are reddish brown with a dull black bill that has a paler base. Its legs are a pinkish brown. Both sexes are similar in appearance. The juvenile bird has spots and streaks that are not as defined as the adult, and its eyes are muddy gray-brown.

Geographic range: Cactus wrens can be found from southeast California to southwest Nevada, and into southern Arizona and New Mexico, as well as southwest Texas through central Mexico. Cactus wrens are also throughout the Baja California peninsula.

Habitat: Cactus wrens inhabit areas that are desert or semi-desert; they also live along arid hillsides and locales that provide them with vegetation such as spiny cacti (KACK-tie, or KACK-tee) and cholla, which is used for nesting.

Diet: Cactus wrens are primarily carnivores (meat eaters), eating invertebrates, animals without a backbone, such as ants, wasps, spiders, and caterpillars, as well as small frogs and lizards. The vegetable matter they consume includes cactus seeds and fruit. They will visit bird feeders and eat pieces of bread and slices of potato or raw apple. They do not need to drink but will if water is available. They tend to be ground feeders, overturning ground litter and stones in order to find their prey.

Behavior and reproduction: Cactus wrens live in pairs or small family groups. When the bird is disturbed, it will run on the ground like a thrasher rather than fly. These birds are often unruly and noisy, with a song that is a loud, harsh series of "jar-jar-jar" notes, usually delivered from the top of a cactus or other perch.

The cactus wren is monogamous (muh-NAH-guh-mus). The breeding nest is an oval-like ball with a side entrance hole that is made of dry grasses and fibers lined with feathers. They are usually located right in spiny cacti and no effort is made to hide them. The female usually lays three to five eggs, though the number can range from two to seven, and they are light brown or pinkish in color with tiny speckles of reddish brown. The female alone incubates the eggs in a period that can last sixteen days. The newly hatched and young birds are fed by both sexes for nineteen to twenty-three days. The cactus wren might attempt up to six broods a year, though usually only three of those are successfully reared.

Cactus wrens and people: The cactus wren is a popular bird for observation due to human familiarity in its habitat. It has been recognized as the state bird of Arizona.

Conservation status: The cactus wren is not a threatened species, and in the most favorable habitats is one of the most common. This adaptable bird seems to need only spiny cactus in order to thrive. ∎

HOUSE WREN (Troglodytes aedon): SPECIES ACCOUNTS

Physical characteristics: The house wren can range in length from 4.6 to 5 inches (11.5 to 12.5 centimeters) with a weight of 0.3 to 0.4 ounces (8 to 11 grams). The bird is plain, mostly gray-brown on its upperparts. It has pale gray underparts, narrow black bars on the sides and lower belly, with wings and tail that have a narrow black barring. Its brown eyes have a pale streak above them, and a narrow pale eye ring. The bill is thin and slightly curved downward. Both sexes are similar, and the young have a dusky mottling on their breasts.

Geographic range: The house wren can be found across North America from the Canadian province of New Brunswick all the way south to California and west to central Alberta and southern British Columbia. It migrates in winter south of its breeding grounds to areas that include South Carolina west to southern Arizona and south to the Mexican state of Oaxaca (wah-HAH-kah).

Habitat: The house wren prefers to dwell in open country with brushy areas, and among abandoned farmland, forest edges, and in well-vegetated suburban areas, as well as open deciduous and coniferous forests in the western part of North America.

Diet: The house wren forages in tangled vegetation and is primarily a carnivore, eating invertebrates that include spiders, caterpillars, and other bugs; it also eats small amounts of vegetation.

Behavior and reproduction: House wrens are either found by themselves or in pairs. They are loud and obvious in their behavior, easily noticeable. They can be bold. When males are beginning to mate, they create "dummy" nests as a part of the courtship ritual. The female eventually joins him, inspecting the nests and making the decision about which one is best for the breeding nest. The bird is a cavity nester, mostly building their nests in such places as abandoned woodpecker holes or tree cavities, or even hornets' nests that are no longer being used. They have also adapted to human-made nest boxes and other artificial nesting sites. The female lays four to eight eggs, which are whitish with small reddish brown spots. Eggs are incubated for thirteen to fifteen days, and done by the female. The young are born helpless, blind, and naked, and stay in the nest for twelve to eighteen days after hatching. The house wren has two to three broods a year.

Cactus wrens and people: This common bird is popular with humans due to being so familiar and so adaptable to artificial nests; as a result it is one of the best-studied birds in America.

Conservation status: These wrens are not threatened. ∎

WINTER WREN (Troglodytes troglodytes): SPECIES ACCOUNTS

Physical characteristics: The winter wren averages 3.6 to 4 inches (9 to 10 centimeters) in length, with an average weight of 0.3 to 0.4 ounces (8 to 11 grams). It is a very small, short-tailed wren marked heavily by bars. Its upperparts are a warm dark brown, with pronounced markings of narrow dark bars on the wing and tail feathers. Its chin and throat are a grayish brown with a descending color that becomes more reddish. Its flanks are also a deep reddish brown with darker bars. The eyes, bill, and legs are brown. Both sexes are similar. The juvenile bird has faint spotting on its chest, and flank bars that are even less distinct.

Geographic range: The winter wren is found across four continents, including North America from Alaska southward to the mountains of California, and eastward across Canada to Newfoundland and south to the mountains of Georgia; wintering all the way south to northern Mexico. It can be found in the Old World from Iceland to Scandinavia, south to Spain, Morocco, Algeria, and Libya; eastward to Russia, Caucasus, Turkey, and Iran; and in central Asia from Afghanistan to eastern Siberia, Japan, China, and Taiwan, including many offshore islands in Europe and east Asia.

Habitat: The winter wren can be found in enormously varied habitats, from the forested areas of North America to the European and Asian bush and woodland areas, as well as in suburban areas and treeless offshore islands with low scrubby vegetation. In fact, it is the only member of the wren family that can be found in Europe.

Diet: The winter wren is primarily an insectivore, or insect-eater, but it is occasionally known to eat spiders and rarely known to eat juniper berries. These birds feed on the forest floor and sometimes along stream banks, scurrying through leaves and brush in a mouse-like manner.

Behavior and reproduction: Winter wrens are protective of their territories during the breeding season, but will sometimes roost communally during the winter with several dozen birds. These birds spend most of their time down in vegetation, hopping through the dense tangles. Flights are always short and low, from cover to cover. Their song is loud and abrasive, with a long series of trills and clear notes.

Winter wrens and people: These birds are both familiar to and popular with humans, and a common subject of folklore in many countries. It is so well known in England that it was given the name of "Jenny Wren."

Conservation status: Winter wrens are not considered to be threatened, and are a generally abundant species throughout their geographic range. ∎

BLACK-CAPPED DONACOBIUS (Donacobius atricapillus): SPECIES ACCOUNTS

Physical characteristics: The black-capped donacobius wren averages in length from 8.5 to 9 inches (21 to 22 centimeters), with a weight of 1.1 to 1.5 ounces (31 to 42 grams). Its appearance makes the bird unique and unmistakable with a head and shoulders that are glossy black, a back that is more of a brown, and a rump that is olive-brown. Its tail feathers are black with noticeable white tips. Its wings are blackish with an obvious white flash at the bottom. The bird has underparts that are a warm yellow with black bars on its side. Its eyes are a bright yellow, and its legs are a dusky green. The black-capped donacobius also has a yellow cheek pouch that can puff out.

Geographic range: The black-capped donacobius can be found from Panama to coastal Brazil and into northern Argentina.

Habitat: The black-capped donacobius can be found in the brushy vegetation over slow-moving rivers and ponds, at sea level and rarely up to 2,000 feet (750 meters), usually lower.

Diet: The black-capped donacobius's diet and feeding habits are unknown.

Behavior and reproduction: The black-capped donacobius is noisy and expressive, with pairs taking part in loud, ritualized displays, and spreading their wings. Their song is a series of loud whistles. The female's song is lower and has a more grating quality than the male, and the birds often join in a chorus.

The black-capped donacobius breeds cooperatively, meaning that the nesting pair usually gets help raising their new hatchlings. This comes from up to two additional birds—usually their own young from the previous year or two. When a pair has no assistants, they raise only one bird. Help increases the brood to two. The nest is an open cup and is most often built near or over the water. Eggs are a purplish white covered with reddish or purplish spots and blotches. The female alone incubates the eggs for sixteen to eighteen days, with both sexes and the helpers feeding the young. The birds gain their flight feathers at seventeen to eighteen days. Adult birds keep their young cool by wetting their body feathers in water. The black-capped donacobius only has one brood each breeding season.

Black-capped donacobius and people: The black-capped donacobius has no significant connection to humans.

Conservation status: Not threatened, probably due to their adaptability throughout their breeding distribution. ∎