The Pallas's Leaf Warbler (Phylloscopus proregulus) is a tiny, brightly patterned warbler that breeds in the taiga and mountain forests of Siberia and China, yet each autumn a small number reach the Swedish coast far outside their normal range, making them a prized rarity for Nordic birders. At around 9 cm long it is almost as small as the Goldcrest, which inspired its Swedish name, and shares that species' compact shape and constantly flicking movements. The plumage is bright yellow-green with a glowing yellow rump, two bold yellow wing bars, and a distinct yellow crown stripe bordered by darker bands, set off by a broad, pale supercilium.
The most frequently heard call is a soft, slightly descending "dju-eet", distinguishing it from the sharper call of the similar Yellow-browed Warbler; song is rarely heard away from the breeding grounds. It does not breed in Sweden — the birds that turn up are almost always young individuals on autumn migration, appearing mainly along the east and south coasts in the first half of October, with counts ranging from a handful to a couple of dozen in a typical year. It forages restlessly and often hangs upside down, tit-like, picking small insects and spiders from the underside of leaves and twigs in bushes and low trees, and the flash of that bright yellow rump as it turns is often the best clue to picking one out among the foliage.
Read about this species in Swedish →