Short-Eared Owl

The short-eared owl, commonly known as the grass owl, the marsh owl, or the prairie owl, is an open country bird. They are among one of the world’s most largely distributed owls. This owl gets its name from the feather tuft on their head that is shaped like an ear. When in flight, they are often referred to as ‘moth-like’.

These owls are similar to long-eared owls (Asio otus), except the tufts of the short-eared owls are rarely visible. Also, the irises of short-eared owls are yellow, whereas long-eared owls have yellow irises. In 1763, Lutheran bishop Erik Pontoppidan first described this species under the name of Strix flammea, but it was later placed under the genus Asio. The species name flammeus is a Latin word meaning “flame-colored”. There are eleven subspecies nominated under the short-eared owl. A few of them are A. f. flammeus,  A. f. cubensis, A. f. domingensis , A. f. portoricensis.

Description

Size: Length: 13 in – 17 in (33 cm to 43 cm)

Weight: Females: 13.4 ounces (379 gm to 400 gm); Males: 11.1 ounces. (206 gm to 314 gm) 

Wingspan: 43 in (1 m)

Body and Coloration: 

These medium size owls have short heads with round facial disks, short necks, and broad wings.
Their eyes are large with bright yellow irises and are black-rimmed. They have brown to tawny plumage, and the tails and wings have stripes. The underparts of their bodies are buff beige and covered in brown streaks.

Like most species of owls, these birds also possess asymmetrical ear openings on either side of their head, covered beneath the feathers. Females are generally larger and have a darker shade than males.

Range and Distribution

This species ranges throughout the Indian subcontinent, Europe, Africa, North America, South America, and Southeast Asia. They can be found anywhere except in Antarctica and Australia.

Habitat

They usually build their nests in tall grasslands. These birds prefer regions like prairies, marshes, dunes, savanna, and tundra. They are also found in stubble fields, small meadows, coastal dunes, and shrubby areas during winter.

Diet

Their diet mainly consists of small vertebrates like voles, shrews, mice, ground squirrels, rats, bats, and moles. Occasionally these owls feed on smaller birds like shorebirds, small gulls, and terns, insects like beetles, caterpillars, grasshoppers, katydids, and roaches, and reptiles. They hunt their prey by swooping down on it from above.

As short-eared owls share the same habitat and similar prey choices with northern harriers, conflicts between two species occur over a caught prey.

Behavior

• Generally nocturnal, these birds can also act diurnally.
• During winter, they show crepuscular behavior, i.e., are most likely to forage during dusk and dawn.
• These owls often fly close to the ground.
• Short-eared owls are among the few known owls who build their nests, doing so on the ground. These nests are usually covered with feathers, grass, or weeds and hidden in low vegetation.
• This owl species is known to migrate. They travel from the northern region to the southern part during winter.
• They wander in a nomadic manner to search for better food supplies when vole populations are low.
• These owls have different calls. Their primary call is a series of a dozen or more hoots. They also use soft musical hooting sounds to announce territorial claims to other predators. Other than this, the short-eared owls also make barking, screeching, screaming, and whining sounds while defending the nests. These owls also have gender-specific calls; the males give repeated and short hoots, while the females let out a shriek similar to a hawk.
• They are not vocal on the wintering grounds.
• If their natural coloration fails to camouflage them in the grassland from the predators, they may pretend to be dead. Also, they sometimes fake having crippled wings to lure away threats.

Lifespan

The short-eared owl has an average lifespan of 4 – 15 years.

Adaptations

• The feather tufts on their head act as camouflage in trees and tall grass.
• Having asymmetrical ear openings helps them to locate prey at night.
• Their flat facial disc gathers sound and directs it to their ears.

Mating and Reproduction

These owls are monogamous. The breeding season occurs February to April, with males and females forming pairs between mid-February and June. During this season male owls engage in fight with each other to impress females. Males also perform a courtship flight followed by 13 to 16 repeated hoots. They fly very high and dive down, clasping their wings. The breeding usually starts in April. Marsh owls breed across Europe, Asia, North and South America, the Caribbean, Hawaii, and the Galápagos Islands.

The females lay eggs every 1-2 days, and incubation begins with the first egg. They are known to lay 1-11 eggs. The eggs hatch after 20-30 days of incubation. The owlets start fledging after 14-18 days. The short-eared owl become sexually mature at one year old.

Predators

Though these owls are birds of prey themselves, they are hunted by many diurnal raptorial birds. Their predators usually include the red-tailed hawk, snowy owl, northern goshawk, bald eagle, and gyrfalcon. Eggs and owlets often get stolen by birds like crows and ravens. Nesting on the ground makes them vulnerable to predators such as coyotes and foxes.

Conservation Status

As per the IUCN, the short-eared owl is classified as “Least Concern” or “LC”. Their estimated global population is 1,200,000 to 2,100,000.

However, they are facing a decline in the southern United States due to habitat loss. This owl species is protected in the United States under the Migratory Bird Treaty Act but is not under the Endangered Species Act list. In New Mexico this species is listed as endangered.

Interesting Facts

• The short-eared owls begin their call while still inside their egg.
• These are one of the only two kinds of owls found in Hawaii.
• The Hawaiian subspecies of the short-eared owls are known as pueo. They are considered “bringers of good luck” and the messenger of their ancestors. “The Battle of the Owls” is a famous legend among the many stories about pueo.