The greenish warbler (Phylloscopus trochiloides) is a small passerine bird belonging to the family Phylloscopidae, commonly referred to as leaf warblers. It is a migratory species that breeds across the boreal and temperate forests of the Palearctic region and winters in South and Southeast Asia.
Taxonomy and Systematics
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Passeriformes
- Family: Phylloscopidae
- Genus: Phylloscopus
- Species: P. trochiliodes
The species was first described by Johann Friedrich Naumann in 1822. It is closely related to other members of the Phylloscopus “warbler” complex and has historically been considered part of a superspecies that includes the Siberian, Arctic, and Western crowned warblers.
Physical Description
The greenish warbler measures 10–12 cm in length with a wingspan of 15–18 cm. Adults possess an overall olive‑green upperparts, a pale yellowish‑white supercilium, and a faint, often indistinct, dark eye‑stripe. The underparts are whitish to pale grey, and the bill is fine, pointed, and dark. Juveniles resemble adults but are generally duller and lack a well‑defined supercilium.
Distribution and Habitat
Breeding ranges extend from the Ural Mountains across Siberia to the Korean Peninsula, northern China, and the Himalayas. During the non‑breeding season, the species migrates southward to the Indian subcontinent, Indochina, and parts of the Malay Peninsula. It inhabits mixed coniferous and broad‑leaf forests, especially in montane and sub‑montane zones, and is often found in dense undergrowth where it forages among foliage.
Behavior and Ecology
- Feeding: Primarily insectivorous, the greenish warbler gleans insects and spiders from leaves and branches. It may also consume small arthropods on the ground.
- Song: Males sing a series of high‑pitched, thin trills and whistles, typically delivered from concealed perches within the canopy. The song is used for territory establishment and mate attraction.
- Breeding: Nesting occurs from May to July, with a cup‑shaped nest constructed from moss, bark strips, and spider silk, usually placed on a low branch or within a shrub. Clutch size ranges from 4 to 6 eggs, which are incubated by both parents for approximately 12–14 days. Fledging occurs about 10–12 days after hatching.
Conservation Status
The International Union for Conservation of Nature (IUCN) classifies the greenish warbler as Least Concern (LC) due to its extensive range and large global population. No major widespread threats have been identified, although localized habitat loss from deforestation may affect certain subpopulations.
References
- BirdLife International. (2022). Phylloscopus trochiloides. The IUCN Red List of Threatened Species 2022.
- Harrap, S. & Quinn, D. (2020). Tits, Nuthatches and Treecreepers. Christopher Helm.
- Svensson, L., Mullarney, K., & Zetterström, D. (2021). Birds of Europe. Princeton University Press.