Restoring grasslands to save bats: The extraordinary flight of the Mexican long-nosed bat
On late summer nights in Mexico's arid grasslands, that run like a spine through the country from Chihuahua to Morelos, bats stream from their caves and vanish into the dark.
The air above the sierra hums with the beat of thousands of bats' wings. No bigger than a human hand, the Mexican long-nosed bat is a fluffy, nectar-feeding species, whose tongue can extend nearly three inches. This adaptation allows them to feed from the clusters of flowers that sit atop agave plants' towering flower spikes.
But this evening many are not on their usual nightly sortie in search of food. Most are pregnant females making the journey north to give birth. This journey is critical - the Mexican long-nosed bat is listed as endangered on the IUCN's Red List - and they must fly more than 750 miles (1,200km) in the course of their migration into Texas and New Mexico and back again in autumn. Along the way, the bats follow a 'nectar corridor' - a chain of deserts, mountains, and grasslands studded with agaves that fuels their migration with the sugary product of the plant's blooming flowers. The bats pollinate the agaves in turn, as they hurl themselves onto the flowers, dispersing pollen from plant to plant along the chain. But, when the chain breaks, both bats and agaves decline.