Yellow-Browed Warbler | Phylloscopus inornatus

Voice

The call makes the species: a loud, penetrating, rising tsoo-eest, two syllables that shoot upwards, strong for so small a bird and repeated every few seconds. That sound is exactly how you find it in a coastal thicket: you hear it three times before you see it once. Hume's Warbler calls flatter and less rising, more a disyllabic tsu-weet or a dry, tit-like wesoo, without the whipped-up ending. The song, rarely heard in Europe, is a high, thin series of a few repeated notes.

Identification

The smallest green bird in the thicket, fresh olive-green above and white below, with a strikingly marked head: a long, broad, creamy-yellow supercilium running well behind the eye, a dark eye-stripe and usually a faint pale stripe along the centre of the crown. The wing shows two pale bars: a broad yellowish-white one across the greater coverts and a shorter, narrower one across the median coverts; the tertials have broad white fringes. The bill is dark with an orange-pink base and the legs are pale brown to flesh-coloured. Never still: it hangs, flicks and hovers at the tips of branches.

Confusion species

Hume's Warbler is the hard one: duller and greyer, with an off-white rather than yellowish supercilium, one clear wing bar and a second that is often nearly absent, an all-dark bill with at most a trace of pale at the base, and dark legs. Pallas's Leaf Warbler is smaller still and far more contrasting: a bright yellow crown stripe, a yellow rump patch that flashes as it hovers, and broader yellow wing bars. Chiffchaff and Willow Warbler are larger, with no wing bars and no crown stripe.

Habitat

Breeds in the Siberian taiga of birch, larch and spruce. On passage in Europe it turns up in coastal copses, dune scrub, sea buckthorn and elder, willows around pools, poplar lines, cemeteries and village gardens — almost always in the outer branches of broadleaved trees, high in the crown or low in the shrub layer, and often in the company of tits and Goldcrests.

Range and movements

Breeds from the Urals into eastern Siberia and normally winters in south-east Asia. Every autumn a proportion drifts west. Along the North Sea and the Atlantic coasts of north-west Europe and Scandinavia, a settled easterly wind in October brings tens to hundreds, concentrated on islands and headlands such as the Wadden islands. In the Mediterranean and Macaronesia it is a vagrant recorded mainly on the Atlantic north coast of Iberia — Galicia, Asturias, the Basque Country —, along the east coast of Iberia and on the Canaries, with more records year on year.

• Resident
• Winter
• Passage
• dark = core range, pale = thinly spread

How and when to look

The first two weeks of October, after a few days of easterly or north-easterly wind, in a coastal copse or dune scrub. Walk slowly, stop every fifty metres and listen; once you hear the tsoo-eest, wait for the tit flock to come through, because Yellow-Browed almost always travels with one. Watch the outer twigs against the sky — that is where the double wing bar shows best.

Conservation status

Not globally threatened, with a very large and stable breeding population in Siberia. The number reaching Europe has risen sharply over recent decades; whether that reflects population growth, a shift in migratory direction or simply more observers who know the call is still unsettled.

Scientific name

Phylloscopus inornatus | (Blyth, 1842)

Blyth described the species in 1842 as Regulus inornatus; because it was later moved to another genus, the author and year stand in brackets. The genus Phylloscopus was introduced in 1826 by Boie. Phylloscopus is Greek, from phullon 'leaf' and skopos 'seeker', from skopeō 'to watch': the bird that searches the foliage. inornatus is Latin for 'plain, unadorned', from in- 'not' and ornatus 'adorned'. The specimen the first description was based on came from near Calcutta.