Cobb's Wren
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Cobb's wren (''Troglodytes cobbi'') is a fairly small (12-13.5 cm)
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 ...
which is
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
Falkland Islands The Falkland Islands (; ), commonly referred to as The Falklands, is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and from Cape Dub ...
. It was formerly classified as a
subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
of the
southern house wren The southern house wren (''Troglodytes musculus'') is a very small passerine bird in the wren family Troglodytidae. It is found from southern Mexico to southern Chile and southern Argentina. The name ''troglodytes'' means "hole dweller", and is ...
but is now commonly considered to be a separate species due to differences in
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
, voice,
ecology Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ...
and
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
. The scientific and common names commemorate Arthur Cobb, an author from the Falkland Islands.


Description

The plumage is brown, greyer on the head and breast and more rufous on the tail. There are dark bars on the
flight feathers Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...
and tail. The bill is long, blackish and slightly curved. The main confusion species is the
grass wren The grass wren (''Cistothorus platensis'') is a species of passerine bird in the family Troglodytidae. It is widely distributed in central and southern America. Taxonomy and systematics The grass wren was described in 1790 by the English o ...
which is smaller with a shorter bill, buff eyestripe and dark streaks on the back and head. Cobb's wrens have a number of buzzing calls, and their song is a series of jumbled trills and whistles. The song can be heard from August to February and varies between individuals, with different males having different song patterns.


Behaviour

The birds typically inhabit dense stands of tussac grass near the coast. They are often found on beaches, searching among
kelp Kelps are large brown algae or seaweeds that make up the order (biology), order Laminariales. There are about 30 different genus, genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is technically not a plant but a str ...
and debris to find small invertebrates such as insects and
amphipod Amphipoda () is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods () range in size from and are mostly detritivores or scavengers. There are more than 10,700 amphipod species cur ...
s. They are tame and can often be approached closely. When disturbed, they prefer to slip away like a mouse between boulders or tussac clumps rather than fly.


Breeding

The nest is a ball of grass lined with feathers and tussac root fibres. It is built on or near the ground among tussac or in a rock crevice. The eggs are pinkish with small reddish spots, three or four are laid in a clutch. The eggs are laid from early October to December, and two broods are probably raised during the breeding season.


Status and conservation

This wren is restricted to small
rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...
-free islands with a population of only 4,500-8000 pairs (1997/1998 estimate). It is fragmented into small populations, which could disappear if their islands were colonized by rats or cats. The bird's habit of feeding and breeding at ground level makes them very vulnerable to predation, unlike the grass wren which lives higher up and can coexist with predators. The plight of Cobb's wren was recently brought to broader attention by being featured as
Canon Canon or Canons may refer to: Arts and entertainment * Canon (fiction), the material accepted as officially written by an author or an ascribed author * Literary canon, an accepted body of works considered as high culture ** Western canon, th ...
's endangered species of the month for the February 2009 issue of ''
National Geographic Magazine ''National Geographic'' (formerly ''The National Geographic Magazine'', sometimes branded as ''Nat Geo'') is an American monthly magazine published by National Geographic Partners. The magazine was founded in 1888 as a scholarly journal, nine ...
''. It has been reclassified as
least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
in 2017 by the
IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
thanks to the control of invasive rats on nearby islands.


References

* Birdlife International (2006
Cobb's Wren - Birdlife Species Factsheet
, retrieved 24/10/06 * * Alvaro Jaramillo, Peter Burke & David Beadle (2003) ''Field Guide to the Birds of Chile including the Antarctic Peninsula, the Falkland Islands and South Georgia'',
Christopher Helm Christopher Alexander Roger Helm (born Dundee, 1 February 1937 – 20 January 2007) was a Scottish book publisher, notably of ornithology related titles, including the ''Helm Identification Guides''. Born in Dundee, he was raised in Forfar, wh ...
, London * Robin W. Woods (1988) ''Guide to Birds of the Falkland Islands'', Anthony Nelson, Oswestry *


External links

*
Photos, videos and observations
at Cornell Lab of Ornithologys Birds of the World
Sounds
on the xeno canto collection {{Taxonbar, from=Q531002 Cobb's wren Birds of the Falkland Islands Cobb's wren Endemic birds of the Falkland Islands