Meet The Incredible White-Winged Fairywren Bird

Life Cycle
The White-winged Fairy-wren (Dirk Hartog Island) is capable of breeding at one year of age (Rathburn & Montgomerie 2003). No specific information is available on the life expectancy but, based on observations of the mainland subspecies M. l. leuconotus, it is likely to be four or five years (ABBBS 1972; Tidemann 1983). No specific information is available on rates of mortality, but in one study on Dirk Hartog Island, only 33.3% of adults (and only 13.5% of adult females) banded were recaptured in the following year (Rathburn & Montgomerie 2003).

The White-winged Fairy-wren (Dirk Hartog Island) is a cooperative breeder. The breeding pair is sometimes assisted by a single auxillary male (Rathburn & Montgomerie 2003) and, based on observations of the mainland subspecies M. l. leuconotus, probably also at times by a single auxillary female, or perhaps by multiple auxillaries of either sex. Auxillaries help the breeding adults to feed and defend the young (Rowley & Russell 1995; Tidemann 1980, 1983).

The White-winged Fairy-wren lays its eggs from June to September or October (Johnstone & Storr 2004; Rathburn & Montgomerie 2003; Whitlock 1921). The female builds a dome-shaped nest from dried grass, dried sea grass Posidonia, flower heads, seed heads, spider silk, insect cocoons, wool, feathers and plant down (Johnstone & Storr 2004; White 1921). The nest is usually placed near the ground in a dense shrub such as Acacia, Atriplex, Hakea, Rhagodia, Scaevola, Sida and Thryptomene (Johnstone & Storr 2004; Rathburn & Montgomerie 2003; Wells & Wells 1974; Whitlock 1921). The birds tend to re-nest in the same immediate area, and often in close proximity to their previous nests (Rathburn & Montgomerie 2003).

Clutches consist of two to four, but most commonly three, eggs (Johnstone & Storr 2004; Rathburn & Montgomerie 2003; Whitlock 1921). The eggs are white with reddish-brown or brownish-red spots and blotches, these sometimes forming a cap or zone at the broader end (Johnstone & Storr 2004; White 1921). The eggs are incubated for about 13 days, and the young remain in the nest for about 12 days after hatching (although they are capable of leaving the nest, if disturbed, from eight days of age) (Rathburn & Montgomerie 2003). No information is available on the period of dependence but, based on observations of the mainland subspecies M. l. leuconotus, the young are probably fed by the adults for three to five weeks after leaving the nest, and some young birds might remain in their natal group after becoming independent and assist their parents to raise a subsequent brood in the same season (Rowley & Russell 1995; Tidemann 1983).

In the single study of breeding success that has been conducted on Dirk Hartog Island, 69% of eggs hatched, and breeding groups reared a mean of 2.1 young to eight days of age (the age at which young are capable of leaving the nest) per breeding attempt. Of the nests observed during the study, about 40% were subject to predation and about 20% were parasitized by Horsfield’s Bronze-Cuckoo Chrysococcyx basalis. Common nest predators included snakes, lizards, Pied Butcherbirds Cracticus nigrogularis, Australian Kestrels Falco cenchroides, and feral cats (Rathburn & Montgomerie 2003). Breeding groups are capable of rearing two broods per season (Rathburn & Montgomerie 2003; Whitlock 1921), and possibly more, given that females will rarely lay three or four clutches in a single season (Rathburn & Montgomerie 2003). (Source)
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