Family Callaeidae - Saddleback, Kokako and Huia

The family Callaeidae is endemic to New Zealand and includes three genera for five species in the order Passeriformes. Only three species are remaining today, the two saddlebacks and the North Island Kokako. The second Kokako (South Island) is probably extinct since 2007, in spite of some sight reports. The fifth species, the Huia, is extinct since the early 20th century.
There are significant differences between the birds of the same genus suggested by genetic studies, but in addition, both saddlebacks (Philesturnus) and kokakos (Callaeas) from North and South Islands shows different behaviour, breeding biology and vocalizations, although they have very similar appearance, except some details in colour of wattles and plumage.

These birds, including the extinct species, have fairly short rounded wings, long rounded tail, and distinctive fleshy wattles at gape, blue or orange, becoming brighter and bigger during displays.
Both kokakos have bluish-grey plumage with cobalt-blue wattles (Northern species) and orange wattles (Southern species), a strong, down-curved black bill and long tarsi.

They are not particularly gregarious. They are usually seen alone or in pairs, and in small family groups after the breeding season. Foraging groups of about ten birds are sometimes observed in autumn.
The kokakos are shy birds, like the extinct Huia. In contrast, the saddlebacks are calling continuously.

The Callaeidae are more often heard than seen, and can be identified by their songs in the early morning. They sing all year round, but especially during the breeding season to attract a mate, and during territorial behaviour. They produce melodious organ-like sounds, but the song of the North Island Kokako is a haunting and mournful series of notes, while the saddlebacks utter harsher chattering which can be a series of loud notes, or shorter series of soft flute-like sounds. The extinct Huia produced peculiar and strange whistles described as soft and melodious. Both sexes sing and perform duets.

They are omnivorous, but the diet may vary among the five species, according to the shape of the bill.
The short down-curved bill of the kokakos is made for eating vegetation such as fruit and leaves, but also flowers and buds, and occasionally nectar and invertebrates. It regularly moves, following the food resources.
The saddlebacks are insect-eaters and use the strong, pointed bill to forage in the leaf litter and in rotting wood, probing among decaying wood and bark of trees to locate the hidden invertebrates.

The translocated saddlebacks occur in lowland beech forests and mixed evergreen forests. Indications from fossil evidence suggest that the North Island Saddleback is adaptable to coastal and montane shrublands.
The Huia occurred in mixed hardwood and podocarp forests, and sometimes beech forest with dense understorey.

They are monogamous and have long-term pair-bonds. The mates often remain together for the life. They maintain the territory throughout the year by calls and songs, threat displays with chases and occasionally physical fights. The territory is an important area where they forage, breed, roost and live all year round.
They breed during the austral spring and summer, and all are solitary nesters.
The courtship displays include the typical “Archangel-Displays”. The male is perched on tree or on the ground. It raises the wings and moves them rapidly in front of its mate. It may carry some vegetation in the bill, but these items are repeatedly dropped. The saddlebacks usually lead the female to a chosen nest-cavity after these displays.
They perform courtship feeding throughout the year, but more often during this period, and this behaviour is used to reinforce the pair-bonds.
All the displays are accompanied by calls and songs.

All the Callaeidae build a cup-shaped nest with sticks and twigs, grass, leaves, moss and lichens, and lined with softer materials. The female builds the nest alone.
The saddlebacks are cavity-nesters and build the nest inside a hole, a tree cavity in trunk or large branch, in rock crevice and even in nest boxes, occasionally on the ground. The kokakos nest among branches of trees and shrubs, usually ten metres above the ground. The Huia built a large saucer nest placed in varying places such as tree fork, dead tree, and hollow in tree, and even near or on the ground, and it was sometimes covered with hanging vegetation.
All these nests are usually well-concealed among vegetation, either high in tree or on the ground.

The clutches often consist of 2-3 eggs, but single-egg clutches are natural too. The female alone incubates and broods the chicks, while the male feeds her on the nest. The incubation usually lasts 18-20 days but it is unknown for the Huia, probably ranging between 16 and 28 days.
The chicks are fed by both parents and fledge between 25 and 37 days according to the species. The young birds still depend on parents for food for some days after fledging, but often for longer period.
Nest failures are caused by small introduced mammalian predators such as rats, mustelids and possums. In the offshore islands free of predators, the failures are due to natural avian predators.

The Callaeidae adults are sedentary. However, they may move to neighbouring territories when water or food resources are restricted. The juveniles often disperse over 1-2 kilometres before to establish their own territory close to their natal area.
It is suggested that the Huia was an altitudinal migrant, but the frequency of these movements is unknown.

They are weak fliers and cannot sustain the height. They only fly over short distances. However, they often use their long legs to propel themselves through the canopy or across the forest floor with long leaps.

Decline and extinction of the members of the family Callaeidae were caused by predation by introduced mammals and habitat destruction and fragmentation with forest clearance.
The South Island Kokako was officially declared extinct in 2007, and the Huia disappeared in the early part of the 20th century.
The North Island Kokako is listed as Endangered, but intensive conservation measures would allow the increase of the numbers from 750 to 1000 pairs by the year 2020.
The North Island Saddleback is currently considered Near Threatened, but the population of 6000/7000 individuals is suggested to be increasing.
The South Island Saddleback’s numbers are slowly increasing and estimated at 1200 individuals, and the species is considered Near Threatened.

The translocation of birds from mainland islands to several offshore islands free of predators, allowed the increase of the populations. Thanks to intensive management of populations and predator control, the numbers of the three extant species of Callaeidae are slowly increasing in their new habitats. Some of them are still present on mainland islands, but they have adapted to their environment on offshore islands.
We hope they will remain for long time the distinctive endemic birds of these beautiful islands.