Aldabra Brush Warbler (Nesillas aldabrana)

Aldabra Brush Warbler

[order] PASSERIFORMES | [family] Acrocephalidae | [latin] Nesillas aldabrana | [UK] Aldabra Brush Warbler | [FR] Fauvette d’Aldabra | [DE] Aldabra-Buschsanger | [ES] | [NL] Aldabra-zanger

Subspecies

Genus Species subspecies Breeding Range Breeding Range 2 Non Breeding Range
Acrocephalus aldabrana
Nesillas aldabrana AF Aldabra Island

Physical charateristics

More diurnal than other owls. Medium-sized bird (L 40 cm). In flight, like a large Sparrowhawk with long tail, small pointed wings, uniformly grey and barring breast. Often seen in clearings, along powerline lanes or similar open places in the forest, frequently perches on top of e.g. telegraph pole. Nests in hollow trees. Feeds mainly on voles. Normally sedentary, though some birds disperse up long distances.

wingspan min.: 74 cm wingspan max.: 81 cm
size min.: 36 cm size max.: 39 cm
incubation min.: 25 days incubation max.: 30 days
fledging min.: 25 days fledging max.: 30 days
broods: 1   eggs min.: 6  
      eggs max.: 10  

Range

Africa : Aldabra Island

Habitat

Arboreal, northern limits closely paralleling southern limits of Snowy Owl, occupying fringes of forest tundra and boreal taiga as far as treeline, and ranging south to edge of forest steppe and cultivated lands. Seeks ready access to clearings, burnt areas, open peatlands, dry eminences or ridges and sparse woodland, including birch, aspen, and mixed woods; avoids dense coniferous forest.

Reproduction

Breeding starts in Finland end of March to late June. In Russia laying begins end of March.
Male advertises potential nest sites, and the female selects one. Nests in cavities on top of broken trunks, natural tree hollows, abandoned holes of large woodpeckers. Will accept nest boxes, and occasionally use a stick nest of a larger bird. Laying normally occurs in April and the first half of May. Clutch sizes are usually between 5 and 13 eggs. Eggs are laid at 1-2 day intervals, and incubated by the female alone for 25-30 days. During this time, the male feeds the female. After hatching, the chicks are brooded for 13-18 days, and leave the nest at 23-30 days, and can fly well by the time they are about 5-6 weeks old. They become independent of their parent’s care towards the end of August. They become sexually mature towards the end of their first year. Pairs are monogamous during breeding season.

Feeding habits

In breeding season, almost wholly small voles with a few small birds and larger mammals; perhaps more birds in winter. Diurnal, and will hunt in bright sunlight; at least when young in nest, will also hunt at night

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