there are over 3,000 registered hunters on hawaii island, and hunting, for both recreation and sustenance, is a common activity on mauna kea. a public hunting program is used to control the numbers of introduced animals including pigs, sheep, goats, turkey, pheasants, and quail. the mauna kea state recreation area functions as a base camp for the sport. birdwatching is also common at lower levels on the mountain. a popular site is "kīpuka pu'u huluhulu", a kīpuka on mauna kea's flank that formed when lava flows isolated the forest on a hill.