[4] The bird was endemic to Lord Howe Island in the Tasman Sea (part of New South Wales, Australia).

Its extinction is almost certainly due to predation by black rats which were accidentally introduced to the island in 1918 following the shipwreck of the SS Makambo there.

Gerygone insularis was also considered a subspecies of a broader taxon which included G. modesta from Norfolk Island and G. igata from New Zealand.

The Lord Howe gerygone had pink eyes, similar to those of an albino rat, and a thin grey bill.

[9] A pregnant Lord Howe gerygone would lay a clutch of three pink-tinged, brown-speckled eggs in a domed nest made up of dry bark, fibres, leaves, grass, moss and wool wrapped together with a spider web suspended from a twig.

(Hull, 1909) The Lord Howe gerygone's diet consisted mostly of small insects and spiders.

This species of bird was very common and found mostly in canopies of the native forests and secondary regrowths on this island.