Abstract
The buff-breasted subspecies Sericornis frontalis laevigaster and olive-breasted subspecies Sericornis frontalis frontalis of the White-browed Scrub-wren Sericornis frontalis intergrade sharply in the region of the McPherson Range; elsewhere in eastern coastal Australia each subspecies varies insignificantly. Congruency of this hybrid zone with hybrid zones in three other pairs of taxa indicates that the scrub-wrens acquired their differences in allopatry and are now in secondary contact.