Thai National Parks

Birds of Thailand

Species of Thailand

Eastern grass owl

Thai: นกแสกทุ่งหญ้า, nok saek thung ya

Binomial name: Tyto longimembris, Thomas Caverhill Jerdon, 1839

The eastern grass owl (Tyto longimembris), or Australian grass owl is a species of owl in the family Tytonidae. They feed predominantly on small rodents.

Though some authorities consider this owl to be conspecific with the African grass owl, T. capensis, other consider it to be a valid species.


The eastern grass owl is a medium-sized owl, similar in size to the barn owl. Adult males measure from 32 to 38 cm in length, while the larger females can measure from 35 to 42 cm. The wingspan is from 100 to 116 cm. The female weighs 460 g while the male weighs 400 g. They have dark brown or tan upper parts with pale spots. They have black and tan bars on its wings and a very pale beak, feathered legs, and dark brown eyes. Like all Tyto owls, it has a heart-shaped facial disk with brown buff and a white bordering.


The eastern grass owl's primary call is like many other tyto owls. A loud, hissing screech but the grass owl's screech is louder than a barn owl's but quieter than a masked owl's.


Studies in parts of Australia have shown that the most common prey is the long-haired rat and the cane rat. Prey are detected from on the wing. The owl uses its long legs to penetrate dense ground cover and seize its prey.


This owl prefers tall grasslands and swamps. Roost areas consist of flattened vegetation within systems of "tunnels" through the swamp vegetation. Nesting is in similar situations.


Eastern grass owls live in eastern, southern and southeast Asia, parts of New Guinea, Australia (mainly in Queensland) and the western Pacific. It has also been found in the coastal islands.

Conservation status

Eastern grass owls are considered "least concern" globally, primarily because of their wide distribution. Within Australia, Tyto longimembris is considered vulnerable on the New South Wales Threatened Species Conservation Act (1995).

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Scientific classification

Tyto longimembris

Common names

  • Thai: นกแสกทุ่งหญ้า, nok saek thung ya

Conservation status

Least Concern (IUCN3.1)

Least Concern (IUCN3.1)

Distribution map of Eastern grass owl, Tyto longimembris in Thailand
  • Chiang Saen District, Chiang Rai
  • Nong Bong Khai Non-hunting Area

Range map of Tyto longimembris in Thailand

Important note; our range maps are based on limited data we have collected. The data is not necessarily accurate or complete.

Special thanks to Ton Smits, Parinya Pawangkhanant, Ian Dugdale and many others for their contribution for range data.

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