[6] The close relationship of this phylogenetic pair is suggested by analyses of both morphological characteristics[7] and genetic loci.

[8] Populations of a common ancestor of the two species are thought to have diverged after becoming fragmented by severe aridity during the Pleistocene.

[13] It is usually found singly or in pairs,[14] in the mid to upper storey of trees and shrubs[4] and is often located by its characteristic, persistent song.

[16] Its plumage can be distinguished from these species by the diagnostic large, white patches at base of its outer tail feathers.

[19] On nearby Garden Island, which is closer to the Australian mainland, the species has been present since European records began.

[9] These vary from open sclerophyll forests, dominated by a broad array of eucalyptus species, to sparse mallee and mulga shrublands.

[20] The nest is a long, oval-shaped, pendent structure, with a hooded entrance near the top and a 'tail' at the bottom.

[4] The western gerygone's song is an irregular series of clear, high-pitched whistles, with a meandering melody.

[19] Although the song isn't loud in volume, its persistence and distinctive tonal qualities are often recognizable from long distances.

[19] If secondary contact is subsequently established with the original, mainland population, breeding birds may no longer respond to each other's songs.

[24] Heat waves in these regions can result in sudden, dramatic, large-scale avian mortality events, with lasting ecological consequences.

[24] The frequency of such events is predicted to increase dramatically in coming decades, due to climate change.

This poses a threat to Australia's inland birds, potentially including some western gerygone populations.

[24] Despite a declining population trend,[1] the western gerygone's conservation status is categorized as least concern by the IUCN[1] and by most Australian state legislation.