Habitat: Grass owls live in large flocks and hunt small nocturnal ground mammals at night, similar to barn owls. As a result, its range and habitat are much more limited, living only in coastal heaths and floodplain grasslands across northern Australia.
Grass owls spend the day sleeping alone on the ground beneath undergrowth, entering via runways. During the night, they fly silently on steadily beating wings, at a height of five to twenty-five meters, over their hunting fields. As soon as they identify prey by sight or sound, they plummet onto it with talons first and bolt it down on the spot, cutting out the entrails, finally nipping off the head and swallowing it, and then breaking it and eating it.
Although the inland population fluctuates with the rises and falls of its primary prey, the long-haired rat (Rattus villosissimus), they roost in lignum and reed beds during plague years, where they breed on rats. The Grass Owls either perish or disperse to Darwin and Melbourne when the plagues crash.
The dangling of their long legs on flushing and landing is often used to distinguish grass owls from barn owls, but barn owls also do this. Grass Owls have patchy, tawny-brown backs, while Barn Owls have freckled, pearl-grey backs.
Adults: Both sexes are similar; females are slightly larger than males. With fine white tips on the feathers, the upper parts are patchy chocolate-brown and tawny. Among the three outermost flight feathers, the three outermost are barred with tawny and dark brown colors. It has a whitish tail with four or five dark bars.
The facial disc is white to pale tawny, with a patch of chestnut around the eyes. Also, facial disc is bordered by a ring of chestnut brown that is frequently incomplete. A cream-white underpart with some brown spots is present on the underparts. Eyes are dusky, and small Bill bones are cere flesh. The feet are gray-brown. The feathers on the lower half are reduced to a few bristles, and the claws are dark.
Immature: They are similar to adults.
Downy Young: Initially white-downed; later tawny-gold-downed.
Voice: The grass owl is normally silent, but when it comes into contact with humans, it makes a harsh, rasping screech. Tweeting and chirping during courtship A young begs softly. In defense, it also makes a hiss and a snapping sound similar to a Masked Owl.
NESTING AND BREEDING: It breeds any time of the year, but most commonly after monsoonal rains in June and March. It sometimes nests in loose communities; however, the mating is apparently temporary. Under vegetation, it nests on a scrape or platform of plant stems under a tussock, accessed by tunnels up to 10 meters long.
Eggs: The grass owl usually lays three to eight eggs on alternate nights. The eggs are dull white and ellipsoidal, measuring 40–45 x 30-33 mm. It is the female who incubates; the male roosts with her during the day and brings her food at night. Both parents feed the young owl. During the preceding weeks, the young leave the nest after four or five weeks, are able to fly at two months, and roost in tunnels outside of the nest.
DISTRIBUTION: The species is found in grasslands and heaths along the Queensland coast south to Manning River, NSW, and on grass banks and reed beds in the Barkly Tableland and channel country of western Queensland. Disperses to coastal Arnhem Land and the Kimberleys in the south and northwest.
There are no races; the Australian race also crosses Indonesia into Southeast Asia. There are other races in Africa and in northern New Guinea. One population appears to occupy coastal eastern Queensland and northeastern New South Wales, while the other inhabits western Queensland and the Northern Territory’s Barkly Tableland and channel country.
In western Arnhem Land, wandering parties occasionally settle on floodplains or the Murray-Darling plains, but they rarely remain for long. It is no wonder that grass owls are rarely seen. Coastal populations appear moderately stable and permanent, predating primarily on canefield rats (Rattus sordidus).
Other names: The Eastern Grass Owl is also referred to by this name.
Size: Grass owls measure between 340 and 380 mm in length.
Grass owls live in large flocks and hunt small nocturnal ground mammals at night, similar to barn owls. Photo credit: Arno Meintjes
