New study reveals overnight flights over Gulf of California and migrations of over 1,000 miles
04.15.25
Austin, TX (April 15, 2025) – A team of scientists from Bat Conservation International (BCI), New Mexico State University, and the National Autonomous University of Mexico, along with a binational network of researchers has discovered that lesser long-nosed bats (Leptonycteris yerbabuenae) are in an elite group of bat species known to fly incredibly long distances. Their study, published in Ecology, reveals that these bats made overnight flights of nearly 117 miles across the Gulf of California and migrate over 1,013 miles between roosts in Mexico. These findings highlight the species’ remarkable endurance and underscore the need for international conservation efforts.
The lesser long-nosed bat depends on nectar and fruits and is known to migrate from southern Mexico to the southwestern United States each year following nectar blooms of columnar cacti and agave plants. While this species is known to migrate seasonally, direct long-distance movements of individuals have never been documented given the challenges of tracking small flying mammals.
“The lesser long-nosed bat is a well-studied species,” says Dr. Theresa Laverty, Assistant Professor in the Department of Fish, Wildlife, and Conservation Ecology at New Mexico State University. “However, long-distance migratory movements aren’t well documented for any bat species due to low recapture rates and the difficulty in tagging small species.”
In the last 10 years, passive integrative transponder (PIT) tags and antenna systems (PIT tag readers) at roost entrances have made possible a system of continuously monitoring of individual bats entering and exiting their roosts.
Through a binational collaboration that started in 2013, researchers marked over 4,000 bats with PIT tags (with the same technology used to microchip pets) and equipped the entrances of 12 roosts with PIT tag antennae and readers. Thanks in part to these technological advances, researchers were able to demonstrate roost connectivity at a range-wide scale, identify migratory stopovers for this species, and show travel over land and sea. At least six pregnant females flew from the coast of Jalisco to Organ Pipe in Arizona, traveling nearly 1,000 miles.
“The results of our monitoring efforts are incredible, showing, among other things, long-distance overnight movements across the Gulf of California,” says Dr. Winifred Frick, Chief Scientist at Bat Conservation International. “These flights require bats to travel for hours over open water, with nowhere to stop or feed along the way. One individual even flew back the next night, making back-to-back trips. It’s impressive to say the least, particularly for such a small-bodied bat.”
Another observation of this study is the movements of this species in and around multiple mountain ranges, including an overnight flight between the Huachuca Mountains in Arizona and the Big Hatchet Mountains in New Mexico.
Observations of movements between roosts also informs conservation efforts –particularly around the management of the nectar and fruit resources these bats require. Certain roosts also seem to act as hubs of connectivity, elevating the importance of protection. Ecosystem services provided by migratory animals, including bats, do not stop and start at map boundaries – meaning that integrated conservation efforts are needed in the United States and Mexico in order for this species to benefit.
“Migration is an important, natural process for all animals, human or not,” says Dr. Rodrigo Medellín, a Professor at the National Autonomous University of Mexico. “This study highlights the crucial importance of collaboration between neighbors to protect shared resources and benefits. Reciprocal telecoupled subsidies such as pollination of columnar cactuses and agaves, can only be understood when two great countries work together. The ability of a small bat that weighs around an ounce being able to migrate at least 2.3 million times its own body length is nothing short of mind boggling. And we are only starting!”
The efforts to PIT tag bats and track their movements has already begun in other species of bats, including in Mexican long-nosed and Mexican free-tailed bats. This study emphasizes that collaboration across borders enabled the discovery of these long-distance movements by lesser long-nosed bats, and that these types of efforts need to continue.
To read the study in its entirety, please visit https://doi.org/10.1002/ecy.70067.
About Bat Conservation International
Bat Conservation International is a global conservation organization dedicated to ending bat extinctions. Our team works worldwide to conserve caves, restore critical habitats in danger, and ensure the survival of the world’s bat species. For more information, visit batcon.org.
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