Contributed article
PORTAL — In a groundbreaking citizen-science discovery, the U.S. Fish and Wildlife Service (USFWS) and Bat Conservation International (BCI) are excited to announce the confirmed presence of Mexican long-nosed bats (Leptonycteris nivalis) in southeastern Arizona. This significant finding expands the known range of this important species and highlights the successful collaboration between conservation organizations and the dedicated efforts of citizen scientists.
The Mexican long-nosed, listed as endangered under the Endangered Species Act, is a species crucial for pollinating desert plants including columnar cacti and paniculate agave. The bat species migrates annually from south-central Mexico to the southwestern United States, spending summer months at a maternity roost in southwest Texas and also in the bootheel of New Mexico. In New Mexico, the Mexican long-nosed bat shares a roost with its “sister species,” the recently delisted lesser long-nosed bat (Leptonycteris yerbabueanae). It’s well known among biologists that the lesser long-nosed bat appears throughout southern Arizona, but it was not known that the Mexican long-nosed bat also spends time in Arizona. Its presence in Arizona presents new opportunities for conservation efforts in the southwestern United States.
This discovery was made possible through the contributions of local citizen scientists in southeastern Arizona, southwestern New Mexico, and the “Species from Feces” lab at Northern Arizona University whose work is integral to developing non-invasive survey methods for bats.
Project participants collect environmental DNA, or eDNA, by swabbing hummingbird feeders that the bats feed on. When bats feed at hummingbird feeders and natural food sources such as agave, they leave traces of their DNA via saliva behind, which can be analyzed in the laboratory to confirm the species.
BCI and partners have also been swabbing agaves for eDNA across west Texas, southern NM, and southeastern AZ along potential migratory routes for the Mexican long-nosed bat. Environmental DNA is often used to survey aquatic species by pumping water through a filter that captures the DNA of fish species, but this discovery highlights the role eDNA can now play in answering research questions about cryptic bat species.
As bats face increasing threats from disease and habitat loss, minimizing their stress while studying them by using non-invasive methods whenever possible is increasingly important.
“The discovery of L. nivalis in Arizona is a great example of the power of environmental DNA assays, and furthers the Species from Feces Lab’s mission to use cutting-edge genetic technology for wildlife conservation,” says Dr. Faith Walker, research professor at Northern Arizona University (NAU) and Director of Genetics of the Species from Feces Team.
Previously, the Mexican long-nosed bat could only be differentiated from the lesser long-nosed bat by capturing the species in hand and measuring the bat’s third finger. These bats echolocate too similarly to be differentiated using acoustic recordings and the two species look nearly identical in photographs. Now, using eDNA to survey these species has not only confirmed the presence of the Mexican long-nosed bat in Arizona, but also sheds light on the bat’s use of hummingbird feeders, a feeding behavior common in the lesser long-nosed bat. Every summer residents in southern AZ, often see groups of bats visiting their hummingbird feeders but up until now, it was not known that the Mexican long-nosed bat followed a similar behavior.
Al Bammann is one of many citizen scientists participating in the project whose observations and data collection played a critical role in confirming the presence of these bats by swabbing his hummingbird feeders in Portal, Arizona. Bammann’s involvement underscores the valuable impact of public participation in wildlife conservation.
Bammann said “Citizen science means that you’re plugging what you discover into something bigger than yourself. It is the bird watcher who reports their daily observations that is helping in the long term… It all helps to understand what is there and what is changing.”
While hummingbird feeders are a useful tool for studying these bats, the overall impacts of hummingbird feeders on these bats are not well understood.
Mallory Davies, a PhD Candidate at Colorado State University, has been studying nectar-feeding bats at hummingbird feeders in southern New Mexico and southeastern Arizona as part of a broader study.
Not all hummingbird feeders are the same to bats, Davies advises. For example, feeders with individual perches should be avoided because bats can become entangled in them. Instead, it’s best to use feeders with a continuous ring at the base. Additionally, people who enjoy bats at their feeders should start to taper the nectar levels starting in October to signal to the bats that it’s time to migrate.
The presence of hummingbird feeders can also attract bats to areas where patio fans and outdoor cats can kill bats, so it’s important to minimize these threats. Natural food sources such as native agaves are always the best option for these species.
This discovery leads to many more research questions on Mexican long-nosed bat roosting and foraging in the region. Further research can hopefully determine how rare the species is in Arizona and whether continued use of eDNA and citizen science efforts will reveal more detections and the extent of range expansion for this endangered bat. Dr. Kristen Lear, Director of Bat Conservation International’s Agave Restoration program, added, “We are thrilled to see the Mexican long-nosed bat officially confirmed in Arizona thanks to the contributions from our citizen science partners. This discovery opens new avenues for research and conservation, and we are grateful for the support of our partners and the public.”
The USFWS and BCI are committed to ongoing research and conservation efforts to support the Mexican long-nosed bat population. For more information on the discovery and how you can help, please visit https://www.fws.gov, and https://www.batcon.org/citizen-science-edna-project-faqs.