Wyvern Island
From Witcher Wiki
Wyvern island can be found in the north central part of the swamp forest outside Vizima, between the Druids' Grove and the Mage's Tower, north of the Golem Cemetery. It features, not surprisingly, a healthy colony of wyverns. In Act II, only regular wyverns are in evidence, but in Act III, the royal wyverns are there, led by Moa, an ancient female.
