Bush birds for the sharp-eyed

Although kaka, takahe and kiwi are among the headline species living at Orokonui Ecosanctuary, the forested valley also harbours some bush birds that are dainty and intriguing, writes Neville Peat.

Orokonui Ecosanctuary's bush birds are a diverse lot.

Most visitors would recognise a fantail, silvereye, tui or bellbird, and some would know a South Island tomtit and its larger cousin, the South Island robin, if they came upon them perching inquisitively, at a rakish angle, on a low branch.

A grey warbler's drawn-out, plaintive warble is familiar enough, too, thanks to the airtime it gets on National Radio's Morning Report programme. Inside the ecosanctuary's visitor centre, the bird calls of many of the birds of the Orokonui Valley forest can be played on push-button command. That on-call bird-call facility makes it a good place to tune in before a walk around the ecosanctuary's network of tracks.

Among the bush birds only a few people might know are two small species: brown creeper/pipipi and rifleman/titipounamu. The ecosanctuary is a great place to get to know them because good numbers of both species live in the forest and shrubland.

The brown creeper (Mohoua novaeseelandiae) is the easier of the two species to spot.

Typically, they move in flocks through the forest canopy and mid-canopy, chirruping cheerfully as they go. Reddish-brown on the upper parts and light buff below, they are cousins of the endangered mohua (yellowhead) and the North Island's whitehead, a long-isolated and old family of New Zealand birds.

Ornithologist Derek Onley, of Waitati, who leads the annual bird surveys at Orokonui, says brown creepers were already present in the valley before the predator fence was built; in fact, they topped the pre-fence averages for five-minute counts.

Bellbird counts have overtaken them on these counts since the fence was completed.

Despite their adaptive nature (they may be found in pine plantations) brown creepers are not well known. Derek believes their name could be off-putting.

"Brown creeper conjures up a little drab, mousey, unexciting bird that clings closely to tree trunks in impenetrable thickets.

In contrast, New Zealand brown creepers are perky, busy little birds that bounce around, hang upside-down and investigate every crevice and cranny in a kanuka tree before scurrying off."

If brown creepers are the industrious "elves" of Orokonui, the rifleman takes on a "fairy" persona. They are almost as invisible as tree fairies.

The South Island rifleman (Acanthisitta chloris) is New Zealand's smallest bird, weighing 6g to 7g and measuring up to 8cm long, with a stunted tail.

Like brown creepers, they lived in the Orokonui forest before the fence building and the predator removal and they also remain in good numbers.

Males are a yellow-green above; females a browner shade.

Insect-eaters, they run along branches and up and down tree trunks like mice, but you need to have a sharp eye to see them moving through the greenery and even sharper hearing to detect their calls. Their standard "zipt-zipt-zipt" call is so high-pitched some people will not hear it.

The rifleman belongs to an ancient and distinctive group of birds, the New Zealand wrens, of which there are only two left - rifleman and the mountain-dwelling rock wren. As a result of their long isolation in New Zealand they have no close affinity to any other group of birds. They are found in many forested areas of the South Island, as high as shrubland above the treeline.

They have a co-operative approach to raising chicks.

Adults other than the parents and sometimes siblings as well, known as "helpers", are often involved with feeding the two to five chicks in a clutch. Holes in trees and bank crevices are their usual nest sites, which they line with feathers, lichen and leaf skeletons.

Both rifleman and brown creeper have just begun a new season's breeding cycle, and Derek Onley's band of bird counters, venturing forth every two weeks until January, will be checking them out along with 24 or so other bird species recorded at the ecosanctuary.

Neville Peat chairs the Orokonui Ecosanctuary trust board. Wild Ways appears in the Magazine section on the first Saturday of the month.