Mérion occidental

Identification

A species of Amytornis, the western grasswren is a small, shy, mainly terrestrial bird. It has brown plumage, finely streaked with black and white, and a long, slender tail. Males are slightly larger than females, with adult males weighing 22–27 g and females 20–25 g. Females develop distinctive chestnut patches on their flanks beneath their wings at 1–2 months old. They are usually found in groups of two or three.

Taxonomie

Nom scientifique

Amytornis textilis

Autorité

(Quoy & Gaimard, 1824)

Ordre

Passériformes

Famille

Maluridés

Genre

Amytornis

Répartition et habitat

The species once occurred through much of southwestern Australia, with an outlying subspecies in the Gawler Ranges of South Australia. The range of the nominate subspecies, which used to inhabit inland locations, has contracted westwards to the Shark Bay region since 1910. The cause is probably the decline in habitat quality resulting from overgrazing, which has reduced the availability of cover and nesting sites. Its preferred habitat is low, often Acacia dominated, semiarid shrubland, no more than a metre in height, that forms densely foliaged clumps and thickets.<p>The Southwest Australian subspecies (A. t. macrourus) is now extinct. Its preferred habitat was dense thickets within a variety of eucalypt communities.

Migration

Resident species

Conservation

The population size of the nominate subspecies (A. t. textilis) has been estimated at 21,500 individuals occurring over an area of 20,000 km2, with an area of occupancy of 1200 km2. The population comprises a large subpopulation within Francois Peron National Park and a second subpopulation consisting of several disjunct groups on nearby pastoral lands. Individuals from both populations were reintroduced to Dirk Hartog Island in 2022. The generation length has been estimated at four years. Although the subspecies has suffered a severe reduction in range and population decline in the past, the remaining population is healthy and stable, and is not considered eligible for listing under Australia's Environment Protection and Biodiversity Conservation Act 1999 (EPBC).<p>The Gawler Ranges subspecies (A. t. myall) has an estimated population of about 8400 mature individuals, with a range area of 12,000 km2 and an area of occupancy of 600 km2. Its generation length has been estimated at 9.7 years and the population trend is one of decrease.

Tendance de la population

declining