Mexican Long-Nosed Bats Migration Confirmed in Arizona

FLAGSTAFF, ARIZONA — Scientists have long suspected that Mexican long-nosed bats migrate through southeastern Arizona, but proof of this has been elusive without capturing and measuring these night-flying creatures.

Recent research has developed a method to differentiate the endangered species from other bats by analyzing saliva left behind when they sip nectar from plants and residential hummingbird feeders.

Bat Conservation International, a nonprofit organization dedicated to preventing the extinction of bat species globally, collaborated with residents from southeastern Arizona, southwestern New Mexico, and west Texas for a saliva-swabbing campaign.

The saliva samples collected along potential migration routes were sent to a lab at Northern Arizona University in Flagstaff, where researchers searched for environmental DNA — or eDNA — to confirm that these bats migrate through Arizona and consider it a part-time home.

The Mexican long-nosed bat has been listed as endangered under the Endangered Species Act since 1988. It is the only bat species in Arizona with such federal protection, playing a crucial role in pollinating cacti, agave, and other desert plants.

In late January, officials from the U.S. Fish and Wildlife Service and the Arizona Game and Fish Department announced this significant discovery, which expands Arizona’s list of bat species to 29. Wildlife managers emphasize that this novel, noninvasive method deserves recognition.

“If we were trying to identify the species in the absence of eDNA, biologists could spend hours trying to catch one of these bats, and even then, you’re not guaranteed success,” stated Angie McIntire, a bat specialist for Arizona’s Game and Fish Department. “By sampling the environment, eDNA gives us an additional tool for our toolkit.”

Every spring, Mexican long-nosed bats embark on a lengthy migratory journey north from Mexico into the southwestern U.S., following the sweet nectar of their favorite blooming plants. They return along the same route in the fall.

The conservation group enlisted ordinary citizens for the mission, equipping them with kits to gather samples from bird feeders throughout the summer and fall.

Inside the university lab, microbiology major Anna Riley extracted DNA from hundreds of samples, using machines capable of detecting the presence of bats. Part of her task involved a steady hand, as she carefully transferred diluted DNA into tiny vials before placing them into a centrifuge.

This meticulous process, sample after sample, vial after vial, took months to complete.

“There’s a big database with DNA sequences of many species, and we could compare our DNA sequences from these samples to what’s in the database,” Riley explained. “It’s a bit like a Google search — you pose your question, plug it into the database, and it reveals that you’ve got a bat, and you have this kind of bat.”

Kristen Lear, from the conservation group, noted that eDNA collection has been successfully used to determine the presence of various wildlife in different environments, prompting the group to try it with bats. “They apparently leave behind a lot of spit on these plants and hummingbird feeders,” Lear said.

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