Grey-faced Buzzard (Butastur indicus):

Biology, Ecology, and Seasonal Presence in the Sundarbans

The Grey-faced Buzzard (Butastur indicus) is a medium-sized migratory raptor whose annual journeys connect the temperate forests of East Asia with the tropical and subtropical landscapes of South and Southeast Asia. Known for its calm soaring flight, keen visual acuity, and strong association with woodland–wetland mosaics, this species occupies a unique ecological niche among Old World buzzards. In the Indian subcontinent, its presence is largely seasonal, with occasional winter records from eastern regions including West Bengal. This article presents a comprehensive, research-based account of the Grey-faced Buzzard, emphasizing its taxonomy, morphology, behavioral ecology, and its relevance to the Sundarbans mangrove ecosystem.

Taxonomy & Classification

The Grey-faced Buzzard belongs to the order Accipitriformes, a group that includes hawks, eagles, kites, and vultures. Within this order, it is placed in the family Accipitridae, which is characterized by strong hooked beaks, powerful talons, and exceptional visual perception. The genus Butastur comprises relatively small, lightly built buzzards adapted for forest-edge hunting rather than open-country soaring. The species epithet indicus reflects early taxonomic associations with the Indian region, although the bird’s primary breeding range lies further east.

Morphology & Field Identification

In the field, the Grey-faced Buzzard is recognized by its compact structure, broad wings with rounded tips, and relatively short tail. When perched, it often adopts an upright posture, scanning its surroundings with deliberate head movements. The species shows subtle but reliable plumage features that distinguish it from other buzzards and hawks encountered during migration.

Male Features

Adult males typically display a greyish-brown face and crown, from which the species derives its common name. The upperparts are brown with faint darker barring, while the underparts are pale buff to whitish, marked with fine streaks across the chest. The eyes are yellow, giving the bird an alert and focused expression.

Female Features

Females are slightly larger and heavier than males, a common trait among raptors. Their plumage tends to be marginally darker, with more pronounced streaking on the underparts. The facial grey may appear less distinct, blending into the surrounding brown tones.

Size & Wingspan

The Grey-faced Buzzard measures approximately 41–46 cm in length, with a wingspan ranging between 102 and 120 cm. Its relatively broad wings allow for efficient soaring during long migratory flights, while still permitting agile maneuvering within forested habitats.

Flight Characteristics

In flight, this species alternates between slow, deliberate wingbeats and extended glides. During migration, it often soars on thermals, conserving energy over long distances. When hunting, its flight becomes more direct and purposeful, with short glides from a perch to the ground.

Habitat & Distribution

Global Range

The Grey-faced Buzzard breeds primarily in northeastern China, the Korean Peninsula, Japan, and parts of the Russian Far East. During the non-breeding season, it migrates southward through East and Southeast Asia, reaching countries such as Myanmar, Thailand, Vietnam, Malaysia, Indonesia, and occasionally eastern India.

Preferred Habitat

Across its range, the species favors forest edges, wooded hills, agricultural mosaics, and wetland-adjacent woodlands. It avoids dense, closed-canopy forests and wide-open plains, instead selecting transitional habitats that provide both cover and access to prey.

Diet & Feeding Ecology

Foraging Technique

The Grey-faced Buzzard is primarily a sit-and-wait predator. From a concealed perch, it scans the ground for movement before launching a swift, controlled descent to capture prey. Its diet is diverse, consisting mainly of insects, amphibians, reptiles, small mammals, and occasionally birds.

Breeding & Reproduction

Nesting Sites

Breeding occurs in temperate forests where nests are constructed high in mature trees. The nest is a sturdy platform of sticks lined with leaves and softer vegetation. Clutch size typically ranges from two to three eggs, with both parents participating in incubation and chick rearing.

Unique Adaptations & Behavioral Ecology

Speed & Agility

Although not among the fastest raptors, the Grey-faced Buzzard possesses sufficient agility to maneuver through woodland edges and capture agile prey such as frogs and lizards.

Camouflage and Nesting Strategy

Its subdued plumage blends seamlessly with tree bark and foliage, offering effective camouflage both when perched and while incubating eggs.

Social Behavior

The species is generally solitary outside the breeding season, though large numbers may be observed migrating together along established flyways.

Occurrence & Seasonal Movement

In India, the Grey-faced Buzzard is considered a rare winter visitor, with sightings mostly reported between October and March. Its occurrence is often linked to favorable weather patterns and suitable stopover habitats.

Preferred Habitat in the Sundarbans Region

Within the Sundarbans, this buzzard is most likely to be encountered along the fringes of mangrove forests, near freshwater channels, embankments, and agricultural interfaces. These zones provide ample prey diversity and suitable perching sites during winter migration.

Ecological Role

As a mid-level predator, the Grey-faced Buzzard helps regulate populations of insects, amphibians, and small vertebrates. Its presence indicates healthy trophic interactions and balanced prey availability within its habitat.

Habitat Alteration

Deforestation, agricultural intensification, and wetland drainage pose long-term threats to this species by reducing suitable stopover and wintering habitats. Fragmentation of forest edges can significantly impact its hunting efficiency.

Conservation Efforts

The Grey-faced Buzzard is currently listed as Least Concern at the global level, yet continued monitoring is essential. Protection of migratory corridors and preservation of wetland–forest mosaics remain key conservation priorities.

Did You Know?

The Grey-faced Buzzard undertakes one of the most visually spectacular raptor migrations in East Asia, with thousands of individuals observed passing through narrow coastal flyways each autumn.

External Reference

For additional scientific and distributional details, refer to the Grey-faced Buzzard article on Wikipedia:

https://en.wikipedia.org/wiki/Grey-faced_buzzard