A large sample ( n = 590) of location-tagged digital photographs was examined to assess regional or subspecific variation in iris colour of the White-browed Scrubwren Sericornis frontalis complex, which may be a diagnostic character misrepresented in the literature. The irides of the western/Spotted Scrubwren group ( maculatus , balstoni , mellori , ashbyi ) were found to be consistently more blue-green in colour compared with the remainder of the complex; this difference approached criteria for diagnosability and matched reported taxon boundaries. Lack of variation within the western group suggests a genetic rather than an ecophenotypic basis. Since juveniles of both groups have similar irides, this difference probably represents the acquisition of yellow-orange pigmentation with maturity in eastern but not western birds.