Mayor Island is the summit of a volcano rising from the sea floor. It's both a wildlife and marine reserve.
Tuhua (Mayor Island) is a dormant shield volcano with a large caldera. It emerged from the sea about 7000 years ago and has several hot springs. Opuahau, the highest peak, reaches 354 metres and the volcanic crater contains two lakes, both near sea level. Lake Aroarotamahine is green and Lake Te Paritu almost black.
A wildlife refuge since 1953, the island is home to many native birds - nectar-feeding bellbirds and tui, wood pigeons, morepork, fantail, kaka (brown parrot), grey warbler, waxeye, kingfisher and, soaring on the thermals, the harrier hawk. Well marked walking tracks lead to the lakes and through the impressively tall forest.
Tuhua is considered special by Maori because its geological make up includes black obsidian, a volcanic glass created by the rapid cooling of silica-rich lava. Obsidian was prized as a cutting tool. Pieces of this natural black glass can often be found on Bay of Plenty beaches.
There's a marine reserve off the northern end of the island - a popular diving spot with amazingly clear water. Beyond the reserve, the waters around Tuhua are prized by game fishermen - marlin, mako and swordfish are regularly caught here.
Several charter companies run trips to the island - enquire in Tauranga or Whangamata.