A gregarious species, the island canary tends to form loose flocks outside of the breeding season, occasionally containing many hundreds of individuals (2) (3). It will also form mixed flocks with linnets (Carduelis cannabina) and goldfinches (Carduelis carduelis) (2).
The island canary is mainly herbivorous, feeding on the seeds of grasses and weeds which it forages for on the ground or among short, seed-bearing plants (2). Fig seeds (Ficus) also feature in its diet, along with blossoms and the buds of leaves and flowers (2) (3). It will also occasionally supplement its diet with insects, especially during the breeding season (3).
The onset of the island canary breeding season is influenced by a number of factors, such as the appearance of fresh, green vegetation, but it is generally thought to begin in January or February, and to last until late June (3) (6). While the male island canary will sing throughout the year, its efforts are intensified during the breeding season when establishing a territory and attracting a mate (3) (7). During this time, the male performs song-flights, in which it flies a short circuit while singing in mid-air, taking off from and landing on a prominent song post (2) (3). The female island canary is thought to prefer particular male song types, probably influenced by songs heard in early life, and will choose to breed with a male that produces this song type (3).
An island canary pair occupies a small territory, with the female choosing the nest site and carrying out most of the nest construction, and the male defending the nest site from rival island canaries (3) (7). The nest is built high up in thick shrubs or trees, and is saucer shaped and usually constructed of grasses, roots and moss and lined with hair and feathers (3).
Between three and four eggs are laid in the nest, with egg-laying peaking in April and June (3). The eggs are pale blue and are incubated for 13 to 14 days before hatching. The young island canaries are then cared for by both of the adult birds (3) (7). Island canary chicks fledge at 15 to 17 days old, and become independent at around 36 days of age (3). An island canary pair can produce two or three broods per year (3).
The island canary is believed to live for up to eight years in the wild (3).