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Sep 07 2011

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Eastern Grass Owl (Tyto longimembris)

Eastern Grass Owl

[order] STRIGIFORMES | [family] Tytonidae | [latin] Tyto longimembris | [authority] Jerdon, 1839 | [UK] Eastern Grass Owl | [FR] Effraie | [DE] Graseule | [ES] Lechuza Patilarga | [NL] Aziatische Grasuil

Subspecies

Monotypic species

Genus

The genus Tyto includes all barn-owls (family Tytonidae) except for the bay-owls (subfamily Phodilinae, genus Phodilus) – that is, the true barn-owls, the grass-owls and the masked-owls collectively making up the subfamily Tytoninae. They are darker on the back than the front, usually an orange-brown colour, the front being a paler version of the back or mottled, although there is considerable variation even amongst species. Tyto owls have a divided, heart-shaped facial disc, and lack the ear-like tufts of feathers found in many other owls. Tyto owls tend to be larger than Bay-owls.

Physical charateristics

The Grass Owl is a medium-sized, ground-dwelling bird (35 cm) with a facial disc typical of the Tyto owls. The upperparts are dark brown, buff and yellow-orange, with fine silvery spots. Underparts are white in the male, and buffy in the larger female, with sparse dark spots. The long legs are mostly bare and in flight protrude well beyond the tail, distinguishing the Grass Owl from the similar Barn Owl. When roosting the posture is tall and upright. The call is similar to a Barn Owl – a hoarse, wavering reedy screech ? sk-air’ or ?skee-air’, also a thin, quavering whistle.

Listen to the sound of Eastern Grass Owl

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Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 34 cm size max.: 36 cm
incubation min.: 31 days incubation max.: 32 days
fledging min.: 58 days fledging max.: 62 days
broods: 0   eggs min.: 3  
      eggs max.: 8  

Range

Oriental Region, Australasia : India to Southeast China, Taiwan, Philippines, Sulawesi, Southeast New Guinea, North, Northeast Australia, New Caledonia. The Grass Owl Has been recorded in coastal areas from around the Manning River in northern New South Wales northwards through Queensland and to Arnhem land but most records are from north-east Queensland. A second population, usually widely scattered, occurs through the arid inland areas of Queensland and the Northern Territory. Usually very rare but may become locally and temporarily common during irruptions of Long-haired Rats inland or Cane Rats in coastal regions. Recorded as vagrant in all mainland States, usually after successful breeding season inland followed by population crash in prey species. Grass Owls are also found in the Philippines, Sulawesi, lesser Sundas, possibly Fiji, Tatwan, southern China, parts of South-East Asia and India. They also occur discontinuously in New Guinea.

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.

Reproduction

They are ground nesters, building the platform nest from grass in dense tussocks of grass or sedges; 3-8 dull white eggs are laid and are incubated for about 42 days. The young fledge at about 2 months.

Feeding habits

Nocturnal hunter, diet includes rodents.

Video Eastern Grass Owl

copyright: Desmond Allen


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Eastern Grass Owl status Least Concern

Migration

Resident with some juvenile dispersal, also migration reoprted in China. Probably nomadic in Australia

Distribution map

Eastern Grass Owl distribution range map

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