Common Name: House Wren
Scientific Name: Troglodytes aedon
Scientific Order: Passeriformes
Scientific Family: Troglodytidae
Appearance: The House Wren is a small, grayish-brown bird with a short tail (length 4.75" [11-13 cm], weight: 0.39 oz [10-12 g]). The head, nape, and back appear uniformly dusky brown, and the throat and chest are light gray. Black or dark brown barring occurs on the flanks, tail, and wings. House Wrens have a light eye ring and a faint eyebrow or superciliary line. Males are slightly larger than females.
Habitat/Where to find: The House Wren is common in open woodlands, woodland edges, shrublands, or anthropogenic areas that resemble this type of habitat, including farmlands, residential areas, gardens, parks, and orchards. The House Wren has a huge geographic range – from southern Canada to Tierra del Fuego in South America. In North America, House Wrens breed in the north from British Columbia east to New Brunswick and south to Arizona, Tennessee, and Georgia.
Sounds: House Wrens produce highly variable, complex vocalizations. Both sexes produce loud, rapid, conspicuous songs. Songs resemble a trilling series of liquid, musical rattles that rise, and then fall in tone. Their call notes are relatively low and soft, consisting of short "ch", "chek", or "cheh-cheh" sounds.
Behavior: House Wrens often appear conspicuous and relatively bold in their behavior. Their flight is fluttering and direct, with rapid, shallow wing beats. When perched, House Wrens often cock their tails upward. House Wrens often invade the nests of conspecifics and other species, evicting any existing eggs and killing nestlings. Males are highly territorial, defending multiple nesting cavities and surrounding areas from other intruding males. Nonbreeding males and nearby resident males make intrusions into other territories for extra-pair copulations and to overthrow the resident breeding male.
Reproduction: As part of the courtship process, territorial males construct multiple nests within their territories in almost every available cavity. One or two females eventually join the male to inspect the nest cavities and select one to complete the nest. Nest cavities include tree cavities, bird boxes, and a great variety of anthropogenic substrates. Nests are constructed from sticks and grass, and lined with a variety of softer material. The female incubates 5-9 white eggs for 13-15 days and later broods the altricial nestlings. Young from 2-3 broods per year are fed by both sexes.
Food Habits: The House Wren diet is composed of a variety of relatively immobile invertebrate prey including insects, spiders, beetles, crickets, grasshoppers, millipedes, and snails.
Vital Statistics: Survivorship of juvenile House Wrens is unknown due to dispersal of young away from their natal areas, but the majority attempt breeding in their first year. Adults are relatively philopatric and approximately 30% return to the same territories between years to breed. The oldest known individuals lived approximately 7 years.
Migration/Dispersal: Most populations of House Wrens in the U.S. and Canada are highly migratory, except those in the extreme southwestern U.S.. Wintering birds occur in southern California, the Gulf Coast States, and Virginia. Surviving adults usually return to the same breeding areas between years, but information on natal dispersal of young is lacking.
