Other Environmental Themes

Nectar Highways

Each spring, pregnant lesser long-nosed bats, some 100,000 strong, leave their wintering grounds in south-central Mexico and head north toward the United States in search of food and a place to bring their offspring into the world. The female bats fly up to 100 miles a night, following a "nectar highway"—a trail of cacti and agave plants that flower at night and bloom in sequence as the bats proceed from south to north. Sustaining themselves on a diet of nectar and pollen, lesser long-nosed bats time their journey to match the blooming schedules of these desert flowers.

Upon finding a suitable roost, typically in Arizona or New Mexico, the females stop to bear their young. Afterwards, they begin the return trip with their pups in tow. The southward journey, like the northward trip, is fueled by agave, cardon, saguaro, and other plants that depend heavily on bats for pollination and seed dispersal.

A host of perils along the 3,000-mile migratory loop is putting nectar bats, as well as their journeys, at risk. Indeed, the lesser long-nosed bat is officially listed as "endangered," along with the greater long-nosed bat, which follows a similar nectar corridor between Mexico, New Mexico, and Texas.

Saving these bats depends, in large part, on protecting their food supply along the length of the migratory path. The hazards are many as buildings, farms, and cattle ranges replace native habitat. Roost sites are lost, as mines are sealed for liability reasons. In Mexico, long-nosed bats are sometimes killed deliberately, with dynamite or poison, when people mistake them for vampire bats that damage livestock. Hopefully this practice will subside as people learn through a new U.S.-Mexican initiative about the importance of nectar bats to desert ecology.

The fate of nectar bats is closely tied to agave, which is used to make mescal and tequila, prized commodities. But bats are the primary pollinator of agave plants; without bats there'll be no tequila. If that comes to pass, conservationists won't be the only ones mourning.