Eastern grass owl

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Eastern grass owl
Eastern-grass-owl-1134817.jpg
CITES Appendix II  [2]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Tytonidae
Genus: Tyto
Species:
T. longimembris
Binomial name
Tyto longimembris
(Jerdon, 1839)
Synonyms
  • Strix candidaTickell, 1833
  • Strix candidusTickell, 1833
  • Strix longimembrisJerdon, 1839
  • Aluco longimembrisMcGregor, 1908
Eastern grass owl (immature) Eastern Grass Owl (immature).JPG
Eastern grass owl (immature)
Eastern grass owl in Laina grassland, Tinsukia, Assam, India EASTERN-GRASS-OWL.jpg
Eastern grass owl in Laina grassland, Tinsukia, Assam, India

The eastern grass owl (Tyto longimembris), also known as Chinese grass owl or Australasian grass owl, is a species of owl in the family Tytonidae. They feed predominantly on small rodents. [3]

Contents

Though some authorities consider this owl to be conspecific with the African grass owl, T. capensis, other consider it to be a valid species. [4]

Description

The eastern grass owl is a medium-sized owl, similar in size to the barn owl. Adult males measure from 32 to 38 cm (13 to 15 in) in length, while the larger females can measure from 35 to 42 cm (14 to 17 in). The wingspan is from 100 to 116 cm (39 to 46 in). The female weighs 460 g (16 oz) while the male weighs 400 g (14 oz). [5] [6] [7] 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.

Subspecies

Call

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.

Hunting

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.

Habitat

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.

Distribution

Eastern grass owls live in eastern, southern and southeast Asia, parts of New Guinea, the Philippines, Australia (mainly in Queensland) and the western Pacific.

Conservation status

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

In Taiwan

The eastern grass owl (Tyto longimembris) is classified globally as “Least Concern,” yet its Taiwan-endemic subspecies, Tyto longimembris pithecops, is rare with a small population. It is legally protected in Taiwan as a Category I species under the Wildlife Conservation Act (1989), a status equivalent to “Endangered.” [8]

Since the 1980s, government-led rodent control programs in Taiwan have resulted in the widespread use of rodenticides in farmland. These chemicals have been linked to mortality in various raptor species that prey on rodents, reptiles, and birds. [9] The detection of anticoagulant rodenticides in deceased raptors, such as the black-winged kite, has raised concerns that the eastern grass owl may also be at risk, as it occupies similar habitats and relies on comparable prey. [9] In addition to the threat of secondary poisoning, afforestation on abandoned farmland has further altered or reduced the subspecies’ suitable open habitats. [3]

In response to these findings, the Taiwanese government gradually reduced the distribution of rodenticides, terminating proactive distribution in 2015. [9] However, farmers can still apply for rodenticides through local agricultural authorities when necessary. In 2021, the Forestry and Nature Conservation Agency of the Ministry of Agriculture (MOA) formally implemented the Ecosystem Service Payment Program for Endangered Species and Habitats. [10] Under this program, the eastern grass owl was designated as a priority species, and farmers receive financial incentives for adopting wildlife-friendly practices, such as refraining from herbicides, rodenticides, traps, and toxic baits, and complying with pesticide residue safety standards. [10] Research initiatives and incentive-based conservation programs have been implemented to support the protection of the eastern grass owl in Taiwan.

References

  1. ↑ BirdLife International (2016). "Tyto longimembris". IUCN Red List of Threatened Species . 2016 e.T22688522A93199574. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22688522A93199574.en . Retrieved 18 November 2021.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 3 Lin, Wen-Loung; Wang, Yin; Tseng, Hui-Yun (2007). "Initial Investigation on the Diet of Eastern Grass Owl (Tyto longimembris) in Southern Taiwan". Taiwania. 52 (1): 100–105. doi:10.6165/tai.2007.52(1).100.
  4. ↑ Christidis, Les; Boles, Walter (2008). Systematics and Taxonomy of Australian Birds. Collingwood, Victoria: CSIRO Publishing. p. 168. ISBN   978-0-643-06511-6.
  5. ↑ Eastern Grass Owl - Tyto longimembris. OWl Pages
  6. ↑ Ali, Sálim (1996). The Book of Indian Birds (12th ed.). Bombay: Bombay Natural History Society. ISBN   978-0-19-563731-1.
  7. ↑ Duncan, James R. (2003). Owls of the World: Their Lives, Behavior and Survival . Firefly Books. pp.  203–. ISBN   978-1-55297-845-0.
  8. 1 2 "A Star of Farming Stewardship:The Eastern Grass-Owl". www.taiwanngo.tw (in Chinese). Retrieved 2025-11-17.
  9. 1 2 3 "ARs Found in Taiwan Raptors". Raptors Are the Solution. Retrieved 2025-12-17.
  10. 1 2 農業部林業及自然保育署. "瀕危動物 - 成果與進度 - 草鴞". conservation.forest.gov.tw (in Chinese). Retrieved 2025-12-17.
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