Swan Goose

The swan goose (Anser cygnoides) is a distinguished member of the waterfowl community, boasting a stature that is both large and long-necked within its genus. The wild individuals of this species can reach lengths of 81–94 cm, making them the longest of the Anser geese, and they tip the scales at a substantial 2.8–3.5 kg, surpassed in weight within their genus only by the greylag goose. The wingspan of these impressive birds stretches from 160 to 185 cm.

Identification Tips

Adult swan geese are characterized by their greyish-brown upperparts, with the larger feathers delicately edged in lighter tones. A maroon hue graces the hindneck and cap, extending just below the eye, while the remiges and underwing are cloaked in blackish tones, complemented by white-tipped rectrices. A slender white stripe adorns the bill base. The underside presents a pale buff, with the lower head and foreneck particularly light and sharply contrasted against the maroon. In flight, their wings present a dark appearance devoid of any striking patterns. The bill, unique among its genus, is a solid black, while the legs and feet are a vibrant orange. The eyes are a deep maroon. Juveniles are somewhat more subdued in coloration and lack the white bill base and dark streaks found on the underside of adults.

Habitat

The swan goose favors environments ranging from steppe to taiga and mountain valleys, always in proximity to freshwater sources.

Distribution

This migratory species breeds in inland Mongolia, Northeast China, and the Russian Far East. During winter, it mainly retreats to central and eastern China, with vagrant individuals occasionally spotted in Japan, Korea, Kazakhstan, Laos, coastal Siberia, Taiwan, Thailand, and Uzbekistan.

Behaviour

Outside of the breeding season, swan geese form small flocks. They are known to graze on plains and stubble fields, sometimes at a considerable distance from water bodies. The breeding season commences shortly after their return from winter quarters in April, with nesting activities beginning around May. Post-breeding, around late August or early September, they congregate in small groups to molt their worn plumage before returning to their wintering grounds.

Song & Calls

The swan goose communicates with a loud, drawn-out, ascending honk, described phonetically as "aang." When alarmed, it emits a more barking honk, typically repeated two or three times in quick succession.

Breeding

Breeding occurs near marshes and wetlands, either as single pairs or in loose groups. The clutch typically consists of 5–6 eggs, sometimes up to 8, laid in a shallow nest constructed from plant material on the ground. The precocial young hatch after about 28 days and reach sexual maturity at 2–3 years of age.

Similar Species

While there are no species strikingly similar to the swan goose, it is important to note the differences between it and other Anser species, particularly in size, coloration, and the unique black bill.

Diet and Feeding

The diet of the swan goose includes sedges, grasses, and water plants. They are known to graze and rarely swim.

Conservation status

The swan goose is currently classified as Vulnerable by the IUCN. Its population is in decline due to habitat loss, excessive hunting, and egg collecting. The estimated total population was between 36,500 and 43,500 individuals in 2023.

Domestication

The swan goose has been domesticated, resulting in breeds such as the Chinese goose and the African goose. These domesticated varieties exhibit significant differences from their wild counterparts, including a prominent bill knob and an upright posture.