Abstract
The non-breeding season distributions of some Phylloscopus warblers are poorly known due partly to the difficulties of field identification. We document the addition of Kamchatka Leaf Warbler Phylloscopus examinandus and Sakhalin Leaf Warbler P. borealoides to the avifauna of Thailand based on five individuals and 12 individuals respectively. All P. examinandus were caught and banded on spring (northwards) migration, while the P. borealoides sample included both autumn and spring birds. Their identity was established through assay of the cytochrome c oxidase subunit I (COI) gene (c. 700 bp) of the mitochondrial genome.
We present biometric data for these birds together with representative samples from the respective sibling species, Arctic Warbler P. borealis and Pale-legged Leaf Warbler P. tenellipes. We suggest that both P. examinandus and P. borealoides winter mainly or predominantly in the Sunda Subregion.
