Conservation matters: Friendly robins are at risk

North Island robins are very friendly.

The robins in New Zealand are not closely related to other robins.

Instead we have North, South and Stewart Island robins, the black robin on the Chatham Islands and the closely related tomtit.

The North Island robin is a separate species from the South and Stewart Island birds.
Robins are sparrow-sized birds with a large head, short neck and round body. They have long legs and stand erect.

Their plumage varies from light grey to darker grey-black with a pale grey-white lower breast and belly. The females are lighter grey than the males and both have short bristles around their bills. They are 18cm long and weigh 35gm.

Robins are naturally tame, sometimes even sitting on your boots. While they spend much of their time on the ground they will also hunt in branches, epiphytes and on trunks finding invertebrates to eat.

They flush prey by foot trembling or wing or tail flicking and will grab insects of any size from aphid to tree weta. If their prey is too large to swallow they take it to the ground and flick it until it breaks into smaller pieces.

They will then stash food away if the meal is too large, hiding it in tree crevices or holes. When food is scarce in summer-autumn they will also eat small berries and fruit.

Robins are naturally tame, sometimes even sitting on your boots.

The Central North Island from Taranaki to the Bay of Plenty is where most mainland robins now live. They survive very well on predator-free islands (Little Barrier, Kapiti) and have been reintroduced to many sites where predator numbers are low (Puketi forest).

Their preference is for moist habitat under a dense canopy with a good ground cover of leaf litter.

Robins can begin breeding from one year of age and can live up to 14. Breeding occurs from September-February.

The female builds a nest in a tree fork or tree fern, the outer layer consisting of twigs, fibres and moss bound together with cobwebs, while the inner lining is moss and grasses.

Two or three eggs are incubated by her for 18 days with the male feeding her every two or three hours during the day, and once the chicks are five days old, he feeds them directly. Chicks fledge at 21 days and are fed by the parents for another five or six weeks.
The biggest threat to these friendly birds is predation.

Possums, feral cats, stoats, rats (especially ship rats) kill eggs, nestlings and fledglings and females on nests. The disproportionate number of female deaths seriously skews the population's sex ratios.

Fortunately good predator control allows the population to double within a year (breeding success 70 per cent vs 20 per cent) and corrects this sex ratio quickly. Large-scale habitat loss has also reduced robin numbers.