Elanus scriptus
SUBFAMILY
Accipitrinae
TAXONOMY
Elanus scriptus Gould, 1842, Cooper Creek, South Australia.
OTHER COMMON NAMES
French: Élanion lettré; German: Schwarzachselaar; Spanish: Elanio Escrito.
PHYSICAL CHARACTERISTICS
13.4–14.6 in (34–37 cm); male about 9.2 oz (260 g); female 11.3 oz (320 g). Distinctive black band around eyes.
DISTRIBUTION
Mainly Central Australia.
HABITAT
Arid and semi-arid grasslands and tree-lined watercourses. Following irruptions may reach more coastal grasslands and open woodlands.
BEHAVIOR
One of the few truly nocturnal accipitrids. Roosts by day in leafy trees, sometimes in colonies of hundreds when not breeding. Follows cycles of main rodent prey, especially long-haired rats (Rattus villosissimus), which plague irregularly every five to 10 years following good rains that fill inland waterways. Breeds when rats abundant, then disperses widely, often reaching coastal areas as rat numbers wane, then usually perish. Presumably a core of adults remains inland to repopulate when conditions allow.
FEEDING ECOLOGY AND DIET
A rodent specialist, mostly long-tailed rat, but also takes other small mammals and lizards, and large insects. Usually hunts by night when main prey active; quarters the ground, hovers, and drops vertically onto prey.
REPRODUCTIVE BIOLOGY
Typically, breeds in loose colonies in coolibahs along inland (arid zone) watercourses whenever food is abundant. Monogamous. Builds a nest of small sticks lined with leaves or dung. Egg-laying mostly in late-winter to spring and autumn. Clutch size is usually four or five incubation about 31 days; nestlings fledge at about five weeks.
CONSERVATION STATUS
Not threatened. Generally rare and rather mysterious due to poor knowledge of movements (here today, gone tomorrow habits) and boom and bust breeding strategy. Some threat from overgrazing of already fragile landscape and breeding colonies sometimes invaded by feral cats.
SIGNIFICANCE TO HUMANS
None known.
