SPECIES

Heuglin's White-eye Zosterops poliogastrus Scientific name definitions

Natalia C. García, Bas van Balen, Josep del Hoyo, Nigel Collar, and Guy M. Kirwan
Version: 2.0 — Published May 20, 2022

Systematics

Systematics History

First described as "Zosterops poliogastra" in 1861, when the genus Zosterops was considered "a very circumscribed and very distinct one, though not very rich in species"(5). Since Zosterops is masculine, it had to be corrected to Zosterops poliogastrus (6).

This species used to include several isolated forms from the East-African highlands: Kikuyu White-eye (Zosterops kikuyuensis), Kilimanjaro White-eye (Zosterops eurycricotus), Mbulu White-eye (Zosterops mbuluensis), Taita White-eye (Zosterops silvanus), and South Pare White-eye (Zosterops winifredae)(7, 8). However, studies of genetic data (e.g., 9, 10, 11) have shown that such an arrangement was unsustainable, with Zosterops poliogastrus sensu lato being polyphyletic with respect to other white-eyes. Research has also suggested that most of these taxa are also vocally distinct from one another (12), but more work is needed to assess levels of divergence.

Zosterops poliogastrus kaffensis was described as a separate species in 1902 (13), and Zosterops poliogastrus kulalensis was described in 1948 as a subspecies of Orange River White-eye (Zosterops pallidus) (3), but based on current information they are retained as subspecies of Zosterops poliogastrus (14).

Geographic Variation

Previous authors (15), employing a quantitative criteria for species delimitation from which scores in brackets given below are derived (16, 17), treated kaffensis and kulalensis as separate species.

Zosterops poliogastrus kaffensis differs from poliogastrus by its strong yellow vs whitish belly [3]; olive-green vs buffy-gray flanks [3]; and deeper yellow throat [1]. Zosterops poliogastrus kulalensis differs from poliogastrus by its paler yellow throat [1]; yellowish vs whitish belly [2]; gray vs buffy-gray flanks [2]; possibly less yellow on forehead (ns); and larger size [heavier and longer-tailed; 2]; adult female is only faintly yellowish white on belly and has paler gray sides and flanks than male, and immature resembles adult female.

Subspecies


EBIRD GROUP (MONOTYPIC)

Heuglin's White-eye (Ethiopian) Zosterops poliogastrus poliogastrus Scientific name definitions

Distribution

Eritrea, and Ethiopian highlands (except the southwest) south to Addis Ababa (also Yabello) and east to Harar; occurs locally in mountains of southeastern South Sudan (Imatong, Dongotona, Didinga).

Identification Summary

11–12 cm. Adult has distinct yellow forehead and forecrown extending to between eyes, white eyering 1–2 mm wide, narrow black line through lores and lower front edge of eyering; crown and upperparts green; flight-feathers and primary-coverts blackish brown, edged green to yellowish green, tail dark brown with narrow green outer edges; chin and throat yellow, breast-sides and band across upper breast pale grey, flanks greyish buff, centre of breast and belly white, sometimes tinged yellow, thighs and undertail-coverts yellow; axillaries pale yellow, underwing-coverts white with yellow tinge; iris brown or hazel; bill black; legs slate to pale grey. Sexes alike.


EBIRD GROUP (MONOTYPIC)

Heuglin's White-eye (Kaffa) Zosterops poliogastrus kaffensis Scientific name definitions

Distribution

Southwestern Ethiopia.

Identification Summary

11–12 cm. Adult is rich green on crown and upperparts, with distinct yellow forehead and forecrown extending to between eyes, white eyering 1–2 mm wide; flight-feathers and primary-coverts blackish brown, edged green to yellowish green, tail dark brown with narrow green outer edges; yellow chin and throat not clearly demarcated from green head-sides, centre of breast to undertail yellow, breast-sides and flanks medium green; axillaries pale yellow, underwing-coverts white with yellow tinge; iris brown or hazel; bill black; legs slate to pale grey. Sexes alike.


EBIRD GROUP (MONOTYPIC)

Heuglin's White-eye (Kulal) Zosterops poliogastrus kulalensis Scientific name definitions

Distribution

Mt Kulal, in northern Kenya.

Identification Summary

11–12 cm. Adult male has relatively narrow eyering margined with black below and on lores, distinct yellow forehead, crown and upperparts green; flight-feathers and primary-coverts blackish brown, edged green to yellowish-green, tail dark brown with narrow green outer edges; dark grey sides and flanks contrast with limited greenish-yellow throat and upper breast, pale yellowish-white mid-ventral streak from breast to yellow vent; axillaries pale yellow, underwing-coverts white with yellow tinge; iris brown or hazel; bill black; legs slate to pale grey. Adult female is only faintly yellowish-white on belly and has paler grey sides and flanks than male.

Related Species

Two of the most recent molecular studies including these species recovered Kikuyu White-eye (Zosterops kikuyuensis) and Northern Yellow White-eye (Zosterops senegalensis) as the two taxa most closely related to Zosterops poliogastrus (18, 11), though relationships between these and other related species still require further research.

Nomenclature

Zosterops poliogastrus and the species it used to be grouped with were given various English names, including 'Montane White-eye,' 'African Montane White-eye,' and 'Broad-ringed White-eye.'

Fossil History

No information available.

Recommended Citation

García, N. C., B. van Balen, J. del Hoyo, N. Collar, and G. M. Kirwan (2022). Heuglin's White-eye (Zosterops poliogastrus), version 2.0. In Birds of the World (S. M. Billerman and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.heuwhe2.02