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Kokako Log 1991 by Sid Marsh

Waihi Gazette August 1991

Waitekauri Valley home to one of New Zealand's rarest birds

Trees and forests from the brow of the Maratoto Saddle in the Waitekauri Valley to Waitekauri itself are home for six of this country's rarest birds - the kokako.

In Waikino, avid nature-lover and biologist Dave King has made the Waitekauri kokako, as he's called them, his special project and has been observing the birds for nearly two years.

What he's found is a sextet of birds, one pair on the slopes of the Maratoto Saddle and the rest singularly distributed evenly down towards Waitekauri.

"In my mind the Waitekauri kokako have been fairly isolated for some time," Dave said.

"I've found with isolated populations, that their singing and socialising gets so much less and that's a problem with working with the birds up there."

"Their song is so reduced and so little in their vocabulary that it backs that theory up. There's also not much reinforcement from neighbouring birds to get them singing."

Dave says recording bird-song and observation problems are also compounded by the fact that the birds sing only at first light and are mainly receptive during the summer months.

The kokako or blue wattled crow live in the forest canopy and are limited in flight. They are unable to fly upwards and they tend to hop from tree to tree or glide through the air because they have shortened wings. They make up for this by being extremely quick across the canopy surface.

"They are related to saddle-backs and the extinct Huia. They maintain pair bonds (partners) and form a territory of about 10 hectares, which they maintain pretty much for life," Dave says.

"Because kokako are territorial, if something happens to damage the forest within the territory, it impacts on them very much because they can't move elsewhere. It's just not in their nature, so it's very important that the integrity of the forest where they live is maintained to a high standard.

"Most of the reason they are dying off is because of tree-felling, the removal of the larger trees and competition from other browsers, like goats and deer, who eat the undergrowth plants and stop regeneration.

"But on a one-to-one competition level the possum is the primary competitor, so possum control is all important. Other animals that have caused them to become rare are rats, stoats and weasels."

Dave's kokako work has its roots in similar research he did for the Forest Service in the Pureora Forest during the Ministry of Agriculture and Fisheries' possum eradication programme in 1985.

"I was involved in the programme to find what the impact of dropping 10-80 poison on population of kokako in the forest, near Taupo, would be."

In 1988 his work in the Pureora ended and a year later he had moved from Rotorua to Whangamata after his partner, Paula Broekhuizen, also a biologist, got a job surveying reserve areas in the Coromandel Ranges. A year later he was on a similar Department of Conservation programme.

"I had done some quick surveys of kokako in the Coromandel when I was working down south and I realised nothing was being done on the kokako population in the Coromandel.

"I applied to the Lotteries Board for a grant to fund a survey and that was backed by the Forest Research Institute in Rotorua, the Hamilton Forest and Bird Society and DOC. I got the grant and have been doing a survey of known populations primarily in the Golden Cross area.