The northern Peru birding route winds inland from the countrys arid Pacific coast, through lowland forests and scrubland dotted with cacti, over the Andes Mountains to the Utcubamba River valley. In a tiny patch of cloud forest, 7,000 feet up along the valleys eastern slopes, lives the elusive marvelous spatuletail, perhaps the most spectacular hummingbird in the world, and one of the rarest.

Weighing as much as a pair of pennies and measuring 10 to 15 centimeters long, the male has a head crested in brilliant blue feathers, its throat a burst of iridescent turquoise. More than half the birds length is devoted to two extravagant tail feathers slender appendages that splay dramatically outward and terminate in flashy violet disks, or spatules, like decorative fans.

Constantino Aucca, a longtime conservationist, has been guiding bird-watchers in Peru for more than 30 years. In the 1990s, he would often bring tourists to this remote area near the town of Pomacochas, the only place on Earth to catch a glimpse of the spatuletail hummingbird.