Australian Reed Warbler

The nesting period has mostly been studied in Australia. It is still not very well known in the rest of the species' range but it seems that in Papua New Guinea and the Solomon Islands, birds may reproduce throughout the year. On the Australian continent, nesting begins in September and ends in February, regardless of the area, with a peak in December. The chosen site is within dense aquatic vegetation. These are reedbeds including phragmites, Baumes and scirpes. It may occasionally be the riparian bushes and shrubs near water points or the surrounding shrubs and bushes. These sites will be chosen by young couples who, arriving late to the area, have no other choice than to move away from the water points. The nest is attached 10 to 250 cm above the water with an average of 80 cm. The chosen materials are collected nearby and the nest is built by both sexes, although the female is more active than the male. The nest, deep, forming a cup, is woven with reeds, feathers, rootlets and fine grasses. It is lined with feathers, mostly black swan feathers. It is tightly bound to 4 or 5 vegetable rods, 8 maximum. Very resistant, the nest can be used for several years and the pair, faithful, often returns to its territory already occupied in the past.

Two to four days after the construction of the nest, the female lays 3 eggs over several days, sometimes 2 and a maximum of 4. They are speckled, pale blue, greenish, whitish gray or pale brown-yellow. She incubates alone between 11 and 16 days from the end of the laying or from the first egg between 15 and 16 days. Incubation mostly takes place at night, the male not feeding the female during the day, so she has to leave the nest to feed herself.The male then joins the female to feed the chicks but the behaviour of the two sexes is different. The male can travel up to 240 metres from the nest to hunt while the female will not leave the reed bed. The young are fed insects and their larvae. In case of bigger captures, the prey is cut up or immersed in water for a moment. Nestlings, the young take flight around the eleventh day and some are still fed up to the 29th day. It happens that the couple does a second nest, this one occurs 14 days after the first one flew away. In this case, a second nest is built above the first one. The same goes for replacement nests, the construction of the nest is then very quick, less than 4 days. The Australian Reed Warbler is parasitized by four species of cuckoo: the Pale Cuckoo, Fan-tailed Cuckoo, Horsfield's Cuckoo and Shining Cuckoo. However, the incidence of parasitism is relatively low and the cause of mortality is quite different. The causes of nest failure are mainly linked to predation from rats and snakes on the eggs as well as meteorological conditions. Heavy rains and, conversely, droughts can lead to the destruction of nests. The rate of flight of the young is equivalent to 1.39 young per nest.