Bats “free tail it back from Mexico

Western mastiff-bat (Eumops perotis).  With a wingspread of
22 inches this bat is the largest bat in North America.  

by Rick LoBello, Education Curator

Have you seen any bats lately?   Biologists have identified 14 species of bats living in the El Paso area and during the month of May it is very possible that you might see one or more hunting at night for insects or migrating north over El Paso to Carlsbad Caverns.  Mexican free-tailed bats are one of the most common species in El Paso and unknown to most people, they are here only from early May to October.  Every year they migrate north from southern Mexico to spend the summer in the northern parts of their range to feed and breed.

Second only to the marvel of the Cavern’s themselves, Carlsbad Caverns Mexican free-tailed bat flight ranks as one of the most fascinating wildlife spectacles in the northern Chihuahuan Desert.  Although bats are minuscule in size compared to larger mammals like Alaska’s caribou and the Pacific Coast’s humpback whales, few wildlife dramas near El Paso can compare to Carlsbad’s main event.  

Every evening from early May through October, swarms of thousands of bats per minute exit the cave’s natural entrance to feed on night flying insects in the nearby Black and Pecos river valleys.  Park visitors packing the amphitheater are amazed at the sight. This is definitely the place to be on a New Mexico summer night.  National Parks like Carlsbad are closed at the moment, but hopefully they will reopen when people can once again be safe from Covid 19.

Entrance to Carlsbad Caverns

Come September Carlsbad’s bat colony begins to migrate south to spend the winter months in Mexico. The migration extends into October or early November as the maternity colony in the park departs the area in smaller groups.  Although much is still unknown about their travel route, we do know that the migration extends at least 800 miles.

Information on Carlsbad Mexican free-tailed travels was first obtained during the 1950s when more than 100,000 bats in Texas, New Mexico and Oklahoma we re tagged with wing bands.  Three Carlsbad individuals were eventually recovered. One traveled to Central Mexico covering over 800 miles in 68 days from September 18 to November 25,1952.

Despite extensive studies in search of banded bats, little is known about the break-up of the Carlsbad colony during the winter months. Do some of the large groups migrating from Carlsbad stay together or do most of them break up into smaller groups or separate as individuals?

By early November, with cooler temperatures and fewer insects flying in the nighttime sky, most of Carlsbad’s Mexican free-tailed bats have already reached the warmer climates of Central Mexico.

The Mexican free-tailed bat colony at Carlsbad Caverns National Park is one of the park’s most outstanding resources. If you miss the bat flight this year be sure to make plans for a visit in the future.  Everyone in El Paso needs to put Carlsbad Caverns and the bat flight on their bucket list.  

Mexican free-tailed bat colony in New Mexico


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