Every year, from late March or early April until about the end of November, the space beneath the Ann W. Richards Congress Avenue Bridge (known just as the Congress Bridge) becomes home to thousands of Mexican free-tailed bats. The colony feeds every night during spring and summer, normally flying out from under the bridge around sunset, and watching them emerge has become a quintessential Austin experience.

But bats do more than just entertain us, though. Most of the bats under the Congress Bridge are pregnant females who have migrated from central Mexico to give birth to a single pup in early June. Each mother bat in the colony consumes close to her body weight in insects every night, including mosquitoes and crop pests such as corn-borer moths.

This natural pest control service is worth billions of dollars to the agriculture industry. (It could be part of the reason Texas named the Mexican free-tailed bat its official state flying mammal.) Other species of bats also eat insects, and some are important plant pollinators.

Yet, these mammals are often under appreciated and misunderstood — no, they don’t get caught in your hair or drink your blood (just one species, in Latin America, feeds on the blood of mammals, usually deer and other large animals). They aren’t blind, either.

Many Texans make annual pilgrimages to Austin to see the famous bats fly. Here's what to know before you go.

Viewing etiquette
Do not shine lights on emerging bats or make loud noises within 100 feet of the bridge, as this can disturb or disorient the animals (and fellow bat-watchers). Don’t fly drones within 20 feet of the stream of bats, as collisions can kill bats and damage drones. Never attempt to capture or handle bats; one that lets you get close is probably sick.

Viewing areas
The Ann and Roy Butler Hike-and-Bike Trail has a short 14-foot wide boardwalk along the north shore with an overlook on the east side of the bridge providing a close-up view of the stream of bats. It is also ADA accessible.

The free Statesman bat observation center at 305 S. Congress Ave. just south of the bridge, has paid parking, an informational display, and a grassy hillside almost right underneath the bridge.

Claim a comfy spot on the deck of Live Oak bar and restaurant at the Four Seasons Austin and watch the bats while sipping an El Murciélago cocktail. The bar created the seasonal mescal-based drink in celebration of its furry neighbors.

Bat tours by boat and paddleboard
For the best views of the bats, hit the water. Book an hour-long bat tour with Capital Cruises, located next to the Hyatt Hotel. The Lone Star Riverboat provides one-hour bat-watching cruises on its smaller boats The Southern Star, The Northern Star, or The Little Star.

Live Love Paddle leads tours that last about two hours to see the bats by kayak. Renting or bringing a kayak and soaking up the bat sights on your own is also an option. Rowing Dock, which is located on the south shore of Lady Bird Lake near Barton Springs, also offers special bat paddles. Details and dates can be found on the company's calendar.

Bat-inspired sights and more
Nightwing, a kinetic bat sculpture from Dale Whistler, graces a traffic island at Barton Springs Road and South Congress Avenue. It provides a less-crowded photo op for those on bat-inspired outings.

The Texas Memorial Museum on the University of Texas campus has the skull and teeth of a Tadarida brasiliensis Mexicana, aka the Brazilian or Mexican free-tailed bat, on display behind a magnifying glass. Look for it in the preserved specimen display case in the Hall of Biodiversity on the fourth floor. You can also learn more about the adaptation of nocturnal animals such as bats here.

Pick up a bat-shaped bottle opener, an Austin snow globe full of flying bats, or a children’s book about bats at the Gift Shop in the Austin Visitor Center at 602 E. Fourth St.

National Bat Appreciation Day on April 17 is a chance to celebrate bats and all their good qualities, including as a famous Austin tourist attraction. The Four Season’s Live Oak will offer its bat cocktail for 25-percent off that day if the bats fly and 50-percent off if they don’t.

Start planning now for the 14th annual Austin Bat Fest, which takes over the Congress Avenue bridge on August 24.