Cobb's Wren
Encyclopedia
Cobb's Wren is a fairly small (12-13.5 cm) wren
which is endemic
to the Falkland Islands
. It was formerly classified as a subspecies
of the House Wren
(Troglodytes aedon) but is now commonly considered to be a separate species due to differences in plumage
, voice, ecology
and morphology
.
and debris to find small invertebrates such as insects and amphipods. 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.
-free islands with a population of only 4,500-8000 pairs (1997/1998 estimate). The species is considered to be vulnerable
to extinction as it is fragmented into small populations which could disappear if their islands were colonized by rats or cats. The birds' 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 the Cobb's Wren was recently brought to broader attention by being featured as Canon's endangered species of the month for the February 2009 issue of National Geographic Magazine
.
Wren
The wrens are passerine birds in the mainly New World family Troglodytidae. There are approximately 80 species of true wrens in approximately 20 genera....
which is endemic
Endemism in birds
An endemic bird area is a region of the world that contains two or more restricted-range species, while a "secondary area" contains one or more restricted-range species. Both terms were devised by Birdlife International....
to the Falkland Islands
Falkland Islands
The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...
. It was formerly classified as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the House Wren
House Wren
The House Wren, Troglodytes aedon, is a very small songbird of the wren family, Troglodytidae. It occurs from Canada to southernmost South America, and is thus the most widely distributed bird in the Americas. It occurs in most suburban areas in its range and it is the single most common wren...
(Troglodytes aedon) but is now commonly considered to be a separate species due to differences in plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
, voice, ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
and morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
.
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 and tail. The bill is long, blackish and slightly curved. The main confusion species is the Grass Wren 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 kelpKelp
Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....
and debris to find small invertebrates such as insects and amphipods. 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 ratRat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
-free islands with a population of only 4,500-8000 pairs (1997/1998 estimate). The species is considered to be vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
to extinction as it is fragmented into small populations which could disappear if their islands were colonized by rats or cats. The birds' 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 the Cobb's Wren was recently brought to broader attention by being featured as Canon's endangered species of the month for the February 2009 issue of National Geographic Magazine
National Geographic Magazine
National Geographic, formerly the National Geographic Magazine, is the official journal of the National Geographic Society. It published its first issue in 1888, just nine months after the Society itself was founded...
.
External links
- Cobb's Wren photos, Mangoverde World Bird Guide