Long-billed Corella Cacatua tenuirostris Scientific name definitions

37–40 cm; 500–600 g. Mostly white, with small 33–34 mm crest; lores and forehead orange-scarlet, with scarlet band across throat ; underwing  and undertail tinged yellow; bill bone-coloured, long (42–53 mm) and slender; eye dark brown with large blue peri­ophthalmic ring. Sexes similar. Scarlet band  across throat distinguishes from both <em>C. pastinator</em> and C. sanguinea. Juvenile has shorter bill and less orange-scarlet.

• Little x Long-billed Corella (hybrid) Cacatua sanguinea x tenuirostris

Riverina of SC New South Wales S to S Victoria and SE South Australia.

Grassy eucalypt woodland  (Eucalyptus camaldulensis, E. fasciculosa, E. ovata, E. melliodora, E. microcarpa) and grassland  , where annual rainfall is 250–800 mm, mainly in winter.

Resighting of individually wing-tagged birds showed that species does not travel long distances; 85% of all such resightings were within 5 km of the capture site, while longest movement was of 77 km. Mean size of large feeding flocks varied with time of year and available food sources, from 419 (sunflower) to 122 (pasture).

Uses specialized bill to dig up underground storage organs of a variety of native plants, many of which have now become rare; corellas now commonly eat two species of introduced onion grass (Romulea) and a variety of cereal crops. They also take grain from standing crops or from the ground . Since 1960’s, they have begun feeding on sunflower (Helianthus annuus), a new crop for the district, available in autumn and winter, which is normally a time of food shortage. Recorded feeding on insect larvae .

Flight call is a nasal bisyllabic or trisyllabic “ke-wheh” or “ke-re-weh”, the latter typically slightly higher-pitched (and higher than C. sanguinea). Alarm calls include loud screeches and braying sounds.

Laying Jul–Oct. Nest is decaying wood at bottom of tree hollow  up to 25 m above ground. Several pairs may nest in one tree, in separate hollows. Usually 2–3 eggs  (1–4); incubation 24 days, by both parents; chick has sparse pale yellow down; nestlings remain in the hollow 55–60 days; fed by parents in hollow, and then for a further 3 weeks after fledging . In exceptionally favourable years, species may breed twice.

Not globally threatened. CITES II. Currently secure; species continues to expand its distribution, and is even afforded pest status in some areas. Future concern over availability of nest-hollows is serious, as it is with most cockatoos. Corellas were abundant before European settlement and thrived (as did Aborigines) on large quantities of a native daisy, murong (Microseris lanceolata), which has a rich underground tuber. After 1837, pastoralists took up most of the Riverina for sheep grazing, and plants like murong became rare, to be replaced by non-tuberous introduced grasses and clovers; corellas fed on cereal crops and were shot and poisoned, so that by 1860’s they had become rare in some places; degradation of native vegetation by rabbits late in 19th century probably accelerated decline of this population. However, decline was suddenly reversed in 1950’s, possibly because numbers of rabbits declined following introduction of myxomatosis as a control agent; besides relieving competition, this also removed the need to poison rabbits, for which grain bait had often been used, with corellas being non-target victims. Recently established in Tasmania, where origins of population uncertain.