Wednesday, April 3, 2019

You can help agaves and bats in southern Arizona

Step outdoors on a warm southern Arizona night and you might be swept up in what naturalist Ralph Waldt calls a "bat tornado" of winged mammals. Residents routinely wake to find that the clouds of bats have drained their hummingbird feeders overnight.

Although nectar-feeding bats are most noticeable in the area, only two of the 30 bats native to Arizona feed from flowers; most Arizona bats eat insects. Both nectar-feeders, Choeronycteris mexicana (Mexican long-tongued bat) and Leptonycteris yerbabuenae (lesser long-nosed bat), visit Cascabel during warm months.
World-wide, the more than 1,300 bat species represent almost a fourth of the over 5,400 mammals. Bats have the agility to catch and eat prodigious amounts of night-flying insects and to pollinate night-blooming flowers atop tall agave stalks and columnar cacti.

Agaves and cacti provide bats a nectar meal in exchange for pollen the bats inadvertently carry among plants. The bats move with the blooms, from southern Mexico in winter to the grasslands of northern Mexico and the southern U.S. in summer.

This elegant partnership evolved over millions of years and is crucial to the survival of both partners. Currently, bats and agaves are both threatened by climate change and the loss of agaves to land clearing, development, and the harvest of wild agave for bacanora, the agave liquor of Sonora.

The lesser long-nosed bat is the more imperiled of the two nectar feeders in this area. Although this bat was removed from the endangered species list by the U.S. Fish and Wildlife Service in 2018, these pollinators are still at risk due to the decline of their nectar sources.

The Borderlands Restoration Network (BRN), in Patagonia, Arizona, works with many partners to protect bats by increasing their agave food supply. You can help both agaves and bats by participating in two of these projects.

BRN and volunteers track the effects of climate change on two native agaves in our area through the USA National Phenology Network's Flowers for Bats campaign. Many plants are blooming earlier as our climate warms. If bats migrate from Mexico on their usual schedule, but Agave parryi and Agave palmeri bloom earlier, the bats might arrive to find nothing to eat.

BRN replants agaves lost from the southwest U.S. and northwestern Mexico as part of Bat Conservation International's Agaves for Bats campaign. Each year, BRN collects agave pups and seed to grow thousands of agaves for planting by landowners.

If you haven't experienced a bat tornado, keep your hummingbird feeders full for the night shift, watch when agaves flower in your area, and plant some agaves at your place. Then step outdoors on a warm southern Arizona night and wait for the whirlwind.

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