Gansu Leaf Warbler

The Gansu leaf warbler, Phylloscopus kansuensis, is a diminutive passerine that flutters through the foliage of China's forests. This avian jewel, slightly larger than its relative, the Pallas's warbler, measures a mere 10 centimeters from beak to tail. It boasts a palette of greenish hues across its upperparts, contrasting with the paleness of its underbelly. A distinctive white supercilium stretches above its eye, complementing the pale central crown stripe. Its wings are adorned with a prominent wingbar, a faint secondary bar, and the tertials edged in a delicate white.

Identification Tips

When endeavoring to identify the Gansu leaf warbler, look for its long white eyebrow-like supercilium and the pale stripe that crowns its head. The single conspicuous wingbar, along with the slight second bar and the whitish edges on the tertials, are key features that distinguish it from its congeners.

Habitat

This species is known to favor deciduous forests, where it can be found flitting about up to an altitude of 3,200 meters. The forests it inhabits are often sprinkled with spruce and juniper, providing a rich tapestry of greenery for this bird to blend into.

Distribution

The Gansu leaf warbler is a resident of China, with its breeding activities confined to the northern provinces of Gansu and Qinghai. The precise location of its wintering grounds remains a mystery, though they are suspected to be in the southern province of Yunnan.

Behaviour

Observations of the Gansu leaf warbler's behavior are limited, but like its relatives, it is likely an active forager, gleaning insects from leaves and branches.

Song & calls

The vocal repertoire of the Gansu leaf warbler is distinct from that of the Pallas's warbler. Its song begins with a thin, high-pitched note, which accelerates into a series of notes before culminating in a trill—a delightful symphony to any birdwatcher's ear.

Breeding

Details on the breeding habits of the Gansu leaf warbler are scant, but it is known to breed in the northern reaches of China, in the provinces of Gansu and Qinghai.

Similar Species

The Gansu leaf warbler was once considered a subspecies of the Pallas's warbler but has since been recognized as a separate entity due to vocal and genetic differences. Its larger size and the pattern of its wingbars can help differentiate it from the Pallas's warbler.

Diet and Feeding

While specific dietary preferences are not documented, it is reasonable to infer that the Gansu leaf warbler, like its congeners, feeds on a variety of small insects and other invertebrates.

Conservation status

The Gansu leaf warbler is currently classified as Least Concern by the IUCN, indicating that, for now, this species does not face an immediate threat of extinction.