The St Kilda wren (''Troglodytes troglodytes hirtensis'') is a small

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...

bird in the

wren Wrens are a family, Troglodytidae, of small brown passerine birds. The family includes 96 species and is divided into 19 genera. All species are restricted to the New World except for the Eurasian wren that is widely distributed in the Old Worl ...

family. It is a distinctive subspecies of the

Eurasian wren The Eurasian wren (''Troglodytes troglodytes'') or northern wren is a very small insectivorous bird, and the only member of the wren family Troglodytidae found in Eurasia and Africa (Maghreb). In Anglophone Europe, it is commonly known simply as ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the islands of the isolated St Kilda

archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands. An archipelago may be in an ocean, a sea, or a smaller body of water. Example archipelagos include the Aegean Islands (the o ...

, in the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

west of the

Outer Hebrides The Outer Hebrides ( ) or Western Isles ( , or ), sometimes known as the Long Isle or Long Island (), is an Archipelago, island chain off the west coast of mainland Scotland. It is the longest archipelago in the British Isles. The islan ...

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

Description

The St Kilda wren is distinguished from the mainland form by its larger size and heavier barring, as well as its generally greyer and less

rufous Rufous () is a color that may be described as reddish-brown or brownish- red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a d ...

colouration. It differs from other Scottish island sub-species by its heavy barring, long and strong bill, and its greyer and paler plumage. The voice is somewhat louder than the mainland subspecies.

Distribution and habitat

This wren is known only from St Kilda in the

, where it is present on all islands in the group. In the breeding season it is largely found on the cliffs and steep rocky slopes with thick vegetation, but also around old buildings. Outside the breeding season it is more widely dispersed around the islands.

Ecology

The St Kilda wren feeds on small

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s such as

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

s and their larvae,

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

larvae,

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

centipede Centipedes (from Neo-Latin , "hundred", and Latin , "foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', "lip", and Neo-Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, ...

s and sandhoppers. Most birds breed in crevices and holes on cliffs concealed behind grasses and dead thrift. Some choose old walls and buildings, or the steep grassy slopes where

puffin Puffins are any of three species of small alcids (auks) in the bird genus ''Fratercula''. These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crev ...

s breed. The nest is built by the male and is rather bulky and is composed of dead grasses,

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

es and bits of dead

bracken Bracken (''Pteridium'') is a genus of large, coarse ferns in the family (biology), family Dennstaedtiaceae. Ferns (Pteridophyta) are vascular plants that undergo alternation of generations, having both large plants that produce spores and small ...

, lined with white feathers moulted by seabirds. There are usually four to six eggs, white with reddish-brown speckles, mostly on the wide end.

Status

The St Kilda wren is a fairly common breeding resident on St Kilda. The population was estimated at 230 breeding pairs in 2002.

References

{{DEFAULTSORT:Saint Kilda wren Endemic fauna of Scotland Fauna of St Kilda, Scotland Troglodytes (bird) Birds described in 1884 1884 in Scotland Taxa named by Henry Seebohm Endemic biota of the Scottish islands Subspecies