Our first "target species," Dean tells us, will be the pueo, or Hawaiian short-eared owl, which is found throughout the islands. The diurnal owl likes to sit on fence posts or the rocky outcrops of old cinder cones now domed and covered with tall grass.

"There's one!" someone in the van yelps. Dean brakes and reverses to line us up with a pueo sitting straight-backed and stoic on a fence post. Later we see another flapping in the distance, searching for rodents in the yellowed grass. I end up seeing 11 pueo over the course of the day. I was born and raised in Hawaii, but having spent most of my life in urban Honolulu, these are the first native owls I've seen. Spotting them is almost worth the tour's $155 price.

We pass old cowboy housing and drive through the U.S. military's training site at Pohakuloa, spotting introduced game species of francolin, wild turkey and pheasant.

The road crosses from Mauna Kea to Mauna Loa's hardened old lava flows. A thick mist bears down on the jagged a'a and ropy pahoehoe, the two types of lava produced by Hawaii's volcanoes.

We reach the trailhead that heads into a forest low on Mauna Loa's northeastern slope. There, Dean hands out rain jackets, sweatshirts, pre-ordered sandwiches and walking sticks. The trail, lined in sections with scraggly ohia lehua trees, leads over the lava field toward the oasis of native forest. Ferns and lichen, normally the first colonizers of cooled lava, grow in clumps where the trees thin out.

Our group picks its way across the cracked lava, stopping occasionally as we near the kipuka to examine bird specimens in distant trees.

As the shade of the koa trees closes over us, Dean, who also expounds upon geology, plants and Hawaiian lore, says we are entering a place Native Hawaiians call the "wao akua" or "realm of the gods."

We tramp the winding path through the forest. Browned sickle-shaped koa leaves (which are technically stems, Dean says) pad the trail.

Dean, a tall, energetic guide who's originally from Canada, stops us every few minutes to scan the trees. I squint dutifully into the forest canopy, but see only a shadowy mat of koa and ohia blocking the sky.

The quick eyes of Dean and tourist Meade Cadot, who leads bird treks in New Hampshire, pick out many native birds over the next couple hours: the grayish oma'o, which feeds on berries; the brown elepaio, trimmed with black and white; the bright red i'iwi and like-hued, but shorter-beaked apapane, found often near lehua blossoms; the yellow and fairly common amakihi; and the endangered Hawaii creeper, one of the plumper forest birds.