The Wallcreeper (Tichodroma muraria) is a small passerine bird found throughout the high mountains of Eurasia. It is the only member of the genus Tichodroma.
Taxonomy and etymology
There is some disagreement among ornithologists
as to where the Wallcreeper belongs in the taxonomic order. Initially, Linnaeus
put it in the family Certhiidae, with the treecreepers
. Now, some authorities place it in its own family, Tichodromadidae
, while others put it in the monotypic Tichodromadinae, a subfamily of the nuthatch
family Sittidae. In either case, it is very closely related to the nuthatches.
There are two subspecies of Wallcreeper:
- T. m. muraria
- T. m. nipalensis is found from Turkmenistan east. It is slightly darker than the nominate race.
The Wallcreeper is a 15.5–17 cm (6—6.75 in) long bird, with a mass of 17–19 grams (0.6–0.7 oz). Its plumage
is primarily blue-grey, with darker flight and tail feathers. Its most striking plumage feature, though, are its extraordinary crimson wings. Largely hidden when the wings are folded, this bright coloring covers most of the covert feathers, and the basal half of the primaries and secondaries.
Distribution and habitat
A bird of the high mountains, the Wallcreeper breeds at elevations ranging between 1000–3000 metres (3250—10000 ft). It is largely resident across its range, but is known to move to lower elevations in winter, when it is occasionally found on buildings and in quarries. Birds have wintered as far afield as England
and the Netherlands
, where one wintered at the University of Amsterdam
This species can be quite tame, but is often surprisingly difficult to see on mountain faces.
The Wallcreeper is an insectivore
, feeding on terrestrial invertebrates—primarily insects and spiders—gleaned from rock faces. It sometimes also chases flying insects in short sallies from a rock wall perch. Feeding birds move across a cliff face in short flights and quick hops, often with their wings partially spread.
The female Wallcreeper builds a cup nest
, sheltered deep in a rock crevice, hole or cave. The nest is lined with softer materials, often including feathers
, and typically has two entrances. The female usually lays 4–5 eggs
, though clutches
as small as three have been found. The white eggs measure 21 mm long, and are marked with a small number of black or reddish-brown speckles. Once her entire clutch has been laid, the female incubates
the eggs for 19–20 days, until they hatch. During incubation, she is regularly fed by her mate. Young are altricial
, which means they are blind, featherless and helpless at birth. Both parents feed the nestlings for a period of 28–30 days, until the young birds fledge. Each pair raises a single brood a year.
Though largely silent, both male and female Wallcreepers sing, the females generally only while defending feeding territories in the winter. The song is a high-pitched, drawn-out whistle, with notes that alternately rise and fall. During the breeding season, the male sings while perched or climbing.
Footnotes and references