Eastern grass owl
The eastern grass owl, 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.
Though some authorities consider this owl to be conspecific with the African grass owl, T. capensis, other consider it to be a valid species.
Description
The eastern grass owl is a medium-sized owl, similar in size to the barn owl. Adult males measure from in length, while the larger females can measure from. The wingspan is from. The female weighs while the male weighs. 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
- T. l. Pithecops – Taiwan. It is mainly found in the southern lowlands and foothills. Locally, it is known in Taiwanese as the “monkey-faced owl” due to its monkey-like facial appearance.
Call
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 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.In Taiwan
The eastern grass owl 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, a status equivalent to “Endangered.”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. 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. In addition to the threat of secondary poisoning, afforestation on abandoned farmland has further altered or reduced the subspecies’ suitable open habitats.
In response to these findings, the Taiwanese government gradually reduced the distribution of rodenticides, terminating proactive distribution in 2015. 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 formally implemented the Ecosystem Service Payment Program for Endangered Species and Habitats. 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. Research initiatives and incentive-based conservation programs have been implemented to support the protection of the eastern grass owl in Taiwan.