Andy Trowbridge / Western Weka (Gallirallus australis australis) close-up portrait. Oparara River, Kahurangi National Park, Buller District, South Island, New Zealand. December, Endangered species.

Andy Trowbridge / Western Weka (Gallirallus australis australis) foraging for food, Oparara River, Kahurangi National Park, Buller District, South Island, New Zealand. December. Vulnerable species.

Andy Trowbridge / Limestone Arch on the Oparara River known as 'Moria Gate'. The Oparara river system has been sculpting the limestone into an intriguing complex of caves, arches and channels for millions of years Opa...

Andy Trowbridge / Giant land snail (Powelliphanta spp.) on wet moss, Oparara River, Kahurangi National Park, Buller District, South Island, New Zealand. January, 2006.

Andy Trowbridge / Nelson Cave Spider (Spelungula cavernicola) covered in dew, sitting on empty egg sack, Oparara River, Kahurangi National Park, Buller District, South Island, New Zealand. January.

Colin Monteath / Oparara River near Oparara Basin Arches, Kahurangi National Park, Karamea, New Zealand

Colin Monteath / Moria Gate Arch with limestone stalagtites on roof, swollen Oparara River, Kahurangi National Park, near Karamea, New Zealand

Colin Monteath / Limestone boulders in Oparara River stained brown with organic matter, Oparara Basin Arches, Kahurangi National Park, near Karamea, New Zealand

Colin Monteath / Moria Gate Arch with limestone stalagtites on roof and swollen Oparara River, near Karamea, Kahurangi National Park, New Zealand

Colin Monteath / Moria Gate Arch with limestone stalagtites on roof and tourist watching swollen Oparara River, Kahurangi National Park, near Karamea, New Zealand

Colin Monteath / Moria Gate Arch with limestone stalagtites on roof and tourist watching swollen Oparara River, Kahurangi National Park, near Karamea, New Zealand

Colin Monteath / Limestone boulders beside rushing Oparara River, Kahurangi National Park

Colin Monteath / Limestone boulders reflected in Oparara River, Kahurangi National Park

Colin Monteath / Oparara Basin Arches with limestone boulders in Oparara River, Kahurangi National Park, near Karamea, New Zealand