Eastern Grass Owl - Tyto longimembris
Calls - Tyto longimembris
Introduction: The Eastern Grass Owl is a medium-sized owl with no ear-tufts and long legs.
[For help with terms used in the description, see parts of an owl. For general characteristics common to most owl species, see owl physiology.]
Description: The facial disc is white for males or with a fawn-coloured wash with most females. The eyes are blackish-brown and the bill whitish-cream.
Upperparts are dark brown with yellowish-ochre flecks and small whitish spots. The wings are very long with three dark bars on the primaries, and wing-coverts similar to the back. The tail is relatively short, with 3 or 4 dark bars.
Underparts are white to whitish-cream with scattered small dark spots. Legs are feathered whitish to about two-thirds down the tarsus, with the lower third and the toes bare, and coloured yellowish-grey. The claws are blackish-brown.
Size: Length 32-42cm.
Wing length 273-360mm. Tail length 114-139mm. Weight 250-582g. Females are larger and heavier than males.
Habits: Nocturnal, but will sometimes fly during the day. This species is adapted for life on the ground, and normally hides in long grass. May breed semi-colonially or groups up to several dozen may hunt in the same area.
Voice: Appears to be more silent than the Barn Owl, the normal call being
a hissing scream similar to a Barn Owl. In loudness and harshness it is about midway
between a Barn Owl and Masked Owl.
Hunting & Food: Numerous species of rodent have been recorded as
prey, long haired Rat and Cane Rat being the most common. Grass Owls, even more than Barn
Owls, are specialist hunters of small rodents and rarely take any other prey. Even though
they weigh much the same as Barn Owls, their wings are considerably longer, reflecting
their method of hunting which is done entirely in flight and never from perches. Hunting
is by low, quartering flight followed by a quick plunge into the grass when prey is
detected. In typical Grass Owl areas, prey is hidden from sight and located and taken
through the combined use of hearing and the very long legs.
Breeding: Grass Owls probably breed at any time of year if conditions are
favourable but, in coastal parts of northern Australia, laying usually occurs between
March and June. The nest is on the ground in dense tussocks of grass or sedges,
particularly bladey grass, usually well away from trees. The nest is a flimsy platform of
grasses which soon becomes trampled and obliterated. It is enveloped in grasses and is
approached by a series of tunnels, usually at least three, which the Owls make by pushing
their way through on foot. One of these is normally the main one and the grass at its
entrance becomes flattened from repeated landing and departures. In the nest, 3-8 dull
white eggs are laid. they are slightly more pear-shaped than other Tyto Owls and measure
40-44mm x 29-32mm. Incubation is thought to be around 42
days (assumed to be similar to the African Grass Owls). The young have a first down of
white and second of warm golden brown. Fledging is at about 2 months. Long before this,
the female stops brooding them and they walk away from the nest to hide in the grass,
returning at night when the adults bring in food. All young appear to fledge in dark
plumage, indistinguishable from adult females.
Habitat: Tall grasslands and swampy country. Dense, well-established
tropical grasslands, particularly with bladey grass or sedges and around cane fields. Also
desert grasslands at times of plagues of long haired Rats. Although rare, they have
colonial tendencies and up to 30 have been recorded in an area of under 100 hectares. They
are rarely seen unless flushed and are generally thought to perch only on the ground but
there have been sightings of birds perching on topmost spray of young pines.
Distribution: From India to Vietnam, North Malay Peninsula and Southeast China, Taiwan, Philippines, Sulawesi, Flores, Southeast New Guinea and Australia. Also found in New Caledonia and Fiji.
Distribution of the Eastern Grass Owl Tyto longimembris
Original Description: Jerdon, Thomas Claverhill. 1839. Madras Journal of Literature and Science, 10, p. 86.
T. l. longimembris,
T. l. chinensis,
T. l. pithecops,
T. l. amauronota,
T. l. walleri,
T. l. baliem,
T. l. papuensis
Page compiled by Deane Lewis. Page last updated 2013-08-21
OwlPages.com Owl Species ID: 010.170.000