Birds in danger

Press, 27 December 1979, Page 13

Birds in danger

The wrybill plover, a unique bird that attracts world-wide interest, would be threatened with extinction if major works were permitted in the Rakaia River. The total population of between 6000 to 7000 birds was too small for risks to be taken by interference with its prime habitat, says a member of the Canterbury branch committee of the Royal Forest and Bird Protection society (Mr B. A. Calder).

The wrybill’s specialised habitat has already been reduced by development of power and irrigation on Canterbury rivers, such as the Rangitata and the Waitaki River in North Otago. The bird, unique in the world for its bill that curves to the right, is nowon the list of "endangered species.

“The value of birds to both the community and

our international standing should not be belittled because they are difficult to measure in financial terms,” Mr Calder says. Intensive studies of the wrybill since 1976 confirm the birds’ specialised breeding requirements; they w’oud be susceptible to any modification of the river.

Mr Calder says the rivers should riot ■be treated individually, but looked at from a wider ecological viewpoint. Bird fauna that had evolved on the, Canterbury rivers was dependent on those rivers remaining in a natural state.

“The society’s policy is that management of these rivers should aim for minimum interference with natural flows and characteristics.” he says.

“It is with the less adaptive species such as the wrybill plover and

black-fronted tern that the situation is most critical. They will not and cannot breed anywhere but on the cleanest, weed-free shingle. New Zealand has an international obligation to protect these species.” The wrybill’s breeding season on the river extends from August to February or March. From limited surveys it appears the Rakaia River held about 20 per cent of the breeding wrybills. Reduction of water flows would reduce the area of braided river channels, leaving the birds with fewer feeding areas and eventually wiping out their remaining habitat.

Wrybill plovers, once plentiful in the lower Rangitata, had not been reported there since the Rangitata diversion race became operational and reduced the river flows downstream.