Stitchbird

INTRODUCTION:
The Stitchbird is one of the rarest birds of New Zealand. This species has been treated as a honeyeater of family Meliphagidae, because it feeds on nectar and has a brush-tipped tongue. But recent DNA analysis showed that the Stitchbird was not a honeyeater at all. Morphological characters, breeding and nesting behaviour make this species unique. It is the sole member of the family Notiomystidae.

The Stitchbird has restricted range and small populations confined to Little Barrier Island. There are small other translocated populations on offshore islands, only increasing thanks to intensive management, but unable to be self-sustaining.
The Stitchbird is also known as Hihi in Maori. It is treated as monotypic species, and listed as Vulnerable.

DESCRIPTION OF THE BIRD:
Biometrics:
Length: 18 cm
Weight: M: 29-42 g – F: 26-35 g

The adult male has black hood and short, erectile white tufts on nape, used during displays. This black hood contrasts with the golden-yellow shoulder patch and a lower breastband, broken in mid-line. It grades to grey-black on mantle, back and scapulars. Rump and uppertail-coverts are dark brownish-olive. The uppertail is blackish-brown with yellowish edged rectrices. The tail is often cocked over the back when the bird is landing or perching.
On the black upperwing, we can see a conspicuous white patch at base of tertials and inner secondary coverts. Other coverts and flight feathers are variously fringed, edged and tipped yellow.

The underparts are brownish-grey with diffuse darker streaks. The underwing is buffy-white with broad, dark grey trailing edge and tip. The undertail is dark brownish-grey.

The slender, slightly decurved bill is black. The eyes are dark brown, surrounded by narrow, dark grey eyering. Legs are pinkish-brown to reddish-brown or dark grey, whereas feet are flesh-coloured.

The female (not displayed) is smaller than male with duller plumage. She lacks the golden yellow shoulder patch and the breastband. She has brownish-olive upperparts. The upperwing pattern is similar to that of male, but mostly black-brown than black, with duller yellow areas.
The underparts are white with brownish-grey wash and indistinct darker streaks.

The juvenile resembles female, slightly browner above and greyish to brownish below. The wing patch is smaller and buff. The pattern of coverts and flight feathers is duller than on adults. The bill is grey-black with paler lower mandible.
The immature resembles adult of corresponding sex, but it is duller overall.

RANGE:
The Stitchbird was formerly present throughout the North Island and Great Barrier, Little Barrier and Kapiti Islands. Once the species disappeared from these regions, the Stitchbird was confined to Little Barrier Island.
After some unsuccessful translocation attempts, the species has been successfully translocated to Kapiti Island, Tiritiri Matangi Island, Karori Sanctuary and Maungatautari.

HABITAT:
The Stitchbird frequents dense, mature, native forest where it breeds, moving sometimes between different forest types according to seasonal flowering and fruiting.
The extinct population of North Island was mostly found in broadleaf evergreen forest.

CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Stitchbird has wide range of high-pitched sounds, and males give louder vocalizations than females.
Contact and alarm calls are often given, and all year round, but the Stitchbird is more vocal during the breeding season.
Males have seven vocalizations, whereas females have five ones. At least one more is shared by both sexes.

The warning call is a “titch” note, giving the bird its name. According to the level of the alarm, this note can be given singly or in accelerating series. Both sexes use this note, and also single-note high-pitched whistles, and a quiet warbler.
During the breeding season, the female utters a loud, single, fast alarm call “pew” during the chases by males, and repeated several times.

The male’s song is a high-pitched whistle “wee-ah-wee” and variants included in the same single song bout. This song is frequently heard at the beginning of the breeding season. Other sounds are given during aggressive, courtship and flight displays.

BEHAVIOUR IN THE WILD:
The Stitchbird feeds on nectar, fruit and small arthropods. It feeds primarily on nectar, and thanks to the long, brush-tipped tongue, it reaches the nectar deep into flowers. Nectar and fruit are taken from numerous plant species. The Stitchbird forages at all levels and occasionally on the ground, but usually in trees and shrubs.
Invertebrates are caught by gleaning from foliage and branches, by probing beneath bark, and by sallying into the air for flying insects. It may forage by hanging upside-down to reach flowers and fruits.
It often faces strong competition for food from other species such as Tui and Bellbird.

At the start of the breeding season, the male sings loudly until the end of the laying. It performs flight displays at the nest-site, to enhance the white and yellow colours, and it raises the white nape tufts.

The Stitchbird has complex mating system and social structure, and numerous interactions occur between the birds of a population.
The mating system may vary from monogamy to polyandry, polygyny or polygynandry, but social monogamy is the commonest.
Polygynandry is a rare mating system among birds, involving multiple male’s partners and multiple female’s partners.
Males copulate with more than one female, and compete for copulation with rivals.

The Stitchbird copulates in two positions. First the common avian method in which the male mounts the female from behind, but also a face-to-face position unique among birds. The latter is usually a forced copulation.
A female is chased to the ground by a male, not her mate. It then mounts her while she is held on her back, so that the birds are face-to-face. The female often tries to escape by spreading her wings or kicking at the male. The repeated loud “pew” uttered by the female during forced copulation can attract other males. But usually, only the first male copulates, while others remain within a metre and call.

During the breeding season, the male defends a small territory around the nest. It is aggressive and chases other males. The female only defends the nesting cavity and can be very aggressive towards other birds, including her own mate. Fights may occur.

They form dominance hierarchies in which older birds are dominant over younger ones, and especially those of the same sex. Males are dominant over females, except when chicks are present at nest.

The Stitchbird is sedentary but it moves within the home range according to the availability of fruit and flowers.
It is a strong flier. It may travel up to several kilometres per day for food.

REPRODUCTION OF THIS SPECIES:
The breeding season occurs during the austral summer, from September/October to February/March, but this period varies slightly within the local populations.
The female builds the nest in hollow, or cavity in tree trunk or branch, or in dead tree or any other cavity, included artificial nest boxes.
This is a platform made with sticks and rootlets, with a cup made from fern rhizomes, bound together with spider web. It is lined with fern scales and feathers. It is usually placed between 6 and 25 metres above the ground.

The female lays 3-5 eggs, but the size of the clutch decreases with later breeding attempts. She incubates alone during 13-19 days, with the male sometimes assisting her. The chicks are fed by both parents but mainly by female. They fledge about 26-32 days after hatching, and still depend on parents for food for up to two weeks after fledging.
The juveniles join crèches about one week after fledging. They are accompanied by adult males. These crèches are thought to have an important function in social development of juvenile birds.

PROTECTION / THREATS / STATUS:
The Stitchbird has restricted range and small populations estimated at 3,000 mature individuals.
The only natural and self-sustaining population is found on Little Barrier Island. Translocated population is estimated at 430 adults (2011/2012).
The extinction on the mainland is due to introduced black rats, but also to avian diseases, and probably to forest loss too in most art of the range.
On spite of intensive management and predator control, the Stitchbird is currently classified as Vulnerable.