| Winter Wren | |
|---|---|
 | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Troglodytidae |
| Genus: | Troglodytes |
| Species: | Troglodytes hiemalis |
The Winter Wren (Troglodytes hiemalis), also known as the Northern Wren, is a very small bird, a member of the mainly New World wren family Troglodytidae, once considered a subspecies of the Eurasian Wren. They are noteworthy among songbirds both because of their amazingly long and complex songs.
It occurs in North America. It is only migratory in the northern parts of its range.
Etymology[]
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 arthropods or to roost. Taxonomy of the genus Troglodytes is currently unresolved, as recent molecular studies have suggested that Cistothorus spp. and Thryorchilus spp. are within the clade currently defined by Troglodytes. A study of individuals in an overlap zone between two divergent subspecies of winter wren in North America (Troglodytes troglodytes hiemalis in Eastern North America and Troglodytes troglodytes pacificus in Western North America), which differ substantially in song and genetics, found strong evidence for reproductive isolation and suggested that the pacificus subspecies be promoted to the species level designation of Troglodytes pacificus.
Description[]
The 9–10.5 cm long Wren is rufous brown above, greyer beneath, barred with darker brown and grey, even on wings and tail. The bill is dark brown, the legs pale brown. Young birds are less distinctly barred.
The plumage is subject to considerable variation, and where populations have been isolated, the variation has become fixed in one minor form or another. There are 12 subspecies. The disputed subspecies orii, the Daito Winter Wren, became extinct around 1940 – if it is indeed a valid taxon and not merely based on an anomaly.
Taxonomy[]
Recent taxonomies of the Troglodytes genus have shown that winter wrens are the most distantly related of all species within Troglodytes, and have shown that two other groups, the timberline wren (Thryorchilus browni) and the four species within the genus Cistothorus, are within the clade defined by all of the Troglodytes. To make Troglodytes monophyletic, Rice et al. (1999) proposed that winter wrens could be placed in their own genus, Nannus. Alternatively, as suggested by Gómez et al. (2005) , Troglodytes could be made more inclusive by assigning the Troglodytes genus to the current Thryorchilus and Cistothorus genera.
By studying the songs and genetics of individuals in an overlap zone between two subspecies of winter wren within North America (Troglodytes hiemalis hiemalis in Eastern North America and Troglodytes troglodytes pacificus in Western North America), a study by Toews and Irwin (2008) found strong evidence of reproductive isolation between the two. The pacificus subspecies has been 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 hiemalis 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.'
Ecology[]
This small, stump-tailed Wren is mouse-like, easily lost sight of when it is hunting for food, but is found everywhere from the tops of the highest moors to the sea coast.
The winter wren nests mostly in coniferous forests, 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.
It is a bird of the uplands even in winter, vanishing into the heather when snow lies thick above, a troglodyte indeed. It frequents gardens and farms, but it is quite as abundant in thick woods and in reed-beds.
When annoyed or excited its call runs into an emphatic churr, not unlike clockwork running down. Its song is a gushing burst of sweet music, loud and emphatic. It has an enormous voice for its size, ten times louder, weight for weight, than a cockerel.
Individuals vary in quality as well as volume of their song. The song begins with a few preliminary notes, then runs into a trill, slightly ascending, and ends in full clear notes or another trill. At all and any season the song may be heard, though most noticeable during spring. Despite its generally mouse-like behaviour, the male may sing from an exposed perch as its whole body quivers from the effort.
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 insects and spiders are its food, but in winter large pupae are taken and some seeds.
Breeding[]
The male Wren builds several nests, up to 6 or 7 in Europe, but fewer in North America. These are called "cock nests" but are never lined until the female chooses one to use.
The normal round nest of grass, moss, lichens 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 eggs are laid in April, and second broods are reared. The eggs of the St. Kilda Wren are marginally larger and often more boldly spotted; six is the usual number.