Where do Mexican free-tailed bats (Tadarida brasiliensis) go when they leave their summer roosts in the American Southwest?

Mexican Free-tailed Bat. @ Bat Conservation International.

What we witness at Bracken Cave, Frio Cave, Carlsbad Caverns and other summer roosts – millions of Mexican free-tail bats in nightly emergence – becomes somewhat elusive in the winter when the bats head south.  Where do millions of migratory bats roost? How far do they travel?

In the 1950s and 1960s, researchers banded large numbers of Mexican free-tailed bats in Texas, New Mexico, Arizona, and Oklahoma to get a good sense of where the migratory bats traveled to and from. Years later, researchers refined their work and identified three winter roosts in Mexico: Cueva de La Boca in the Mexican state of Nuevo León,  and Cueva de La Isla Janitzio in Michoacán, and an estimated colony of 10,000 bats at La Gruta de Quintero in Tamaulipas.

Bat Conservation International,  the National Park Service at Carlsbad Caverns, and other partners continue research on the wintering patterns of Mexican free-tail bats in these locations. The National Park Service notes:

“The fact is that despite being one of the most numerous mammals in the Southwest, the whereabouts and status of winter populations of these animals are still largely unknown. Learning the answers to these questions is of great interest for ecologists and natural resource stewards, who cannot develop sound conservation strategies without some knowledge of the bats’ winter habits.”


  • La Gruta de Quintero is located in the southern part of the Mexican state of Tamaulipas. The nearest city is Mante and the nearest small town is Quintero. Consult Visit Mexico for travel information and advisories.