Document ID: chunk:federal_register_of_legislation:F2024L01095:body:0:p18
Version: federal_register_of_legislation:F2024L01095
Segment Type: other
Provision Reference: 
Character Range: 46421–49101

in separate mounds tended by the same male (Weathers et al. 1990), and there is genetic evidence of extra-pair paternity and of egg-dumping (Cope et al. 2014). Malleefowl tend to breed annually except in drought years (Frith 1959, Booth & Seymour 1983). The mound comprises a large mass of sand, usually 3–5 metres in diameter and up to one metre high, in which up to a cubic metre of moist litter is buried. The construction of this incubator-mound involves several months of intermittent work (autumn to spring) by both members of a pair, but when the mound is completed (early spring) the sexes lead mostly separate lives (Frith 1959). The male then spends several hours most days maintaining the condition of the mound and regulating the incubation temperature, while the female spends most of her time feeding for egg production and may only visit the mound to lay. Early in the breeding season the heat for incubation of the eggs is produced by microbial decomposition of the litter, but late in the season heat from the sun is also utilised (Frith 1956). The main function of the litter incorporated into the mound appears to be to enable the birds an early start to egg laying. Successful mounds that have been built without leaf litter have been recorded (Frith 1959; P Burton pers. comm. cited in Benshemesh 2007b) but these appear to be rare and are built in early summer rather than spring.

Egg laying usually begins in September and an egg is laid every 5–9 days until mid to late summer (Frith 1959; Benshemesh 1992; Priddel & Wheeler 2005; Ryan-Colton et al. 2011; Hedger 2014, Blythman 2021). The incubation period of eggs varies with temperature but is about 60 days at typical nest temperatures (Frith 1959; Vleck et al. 1984; Booth 1987b). Seven detailed studies have been conducted on the breeding success of Malleefowl, all of which were in south-east Australia (Frith 1959; Booth 1987b; Brickhill 1987b; Benshemesh 1992; Benshemesh & Burton 1997; Priddel & Wheeler 2005; Ryan-Colton et al. 2011). Average clutch size varied between years and localities but was often 15–25 eggs of which about 60–80 % hatched unless a high proportion of mounds were disturbed by predators (Frith 1959; Benshemesh & Burton 1997), unseasonal weather conditions (Brickhill 1987b) or drought. Much of the variation in clutch size is due to the duration of the egg-laying season, which is thought to depend on food supply and the onset of very hot weather. Egg size varies considerably both between years and studies, and there is some evidence that egg size is related to the survivorship of chicks (Benshemesh 1992). The availability of food (Frith 1959; Booth 1987b; Priddel &