Everything you need to know about Austin’s Congress Bridge Bats

Congress Bridge Bats in Austin, Texas

Most of the visitors that venture into Austin, Texas have heard of the city’s reputation for being home to a colony of Mexican Free-Tailed Bats.  Often overlooked, however, is the fact that Ann W. Richards Congress Avenue Bridge over Lady Bird Lake is one of the few locals that bats truly inhabit, and it is one of the biggest colonies of urban bats on the entire planet.  Many bat watchers from around the globe visit the Congress Bridge between Spring and Fall, to witness these majestic-winged creatures in flight.

The Congress Avenue Bridge Bats take flight out for their nightly feeding. A truly spectacular sight to behold.

If you are familiar at all with bats, you know that they are nocturnal creatures by nature, and as the sun sets, they take flight, looking to consume any and all unsuspecting insects that happen to be airborne.  With a flight speed of 60 miles per hour, insects do not stand a chance, leaving  spectators awestruck by the bats amazing and erratic flight patterns.  Each evening, the flight path of the bats is unique and different from the previous, creating anticipation as bat enthusiasts await the cacophony of nocturnal, leathery wings.

Generally, the bats known simply as “scouts” will break the cavern enclosure initially, ensuring that no predators are waiting nearby.  The scouts will then signal the remaining bats that all is clear causing up to three massive streams of bats to rocket out of the cave and take to the skies!

Austin Bat Fest

Once a year, Austin, also known as “Bat City”, hosts an extravagant celebration in honor of the Mexican Free-Tails.  People from all around gather together to celebrate these mammals with food, professional vendors, and music.  Tourists, bat aficionados, and locals alike, all take pride in and cherish this annual event.

Thousands gather on the Congress Avenue Bridge for Bat Fest, Austin’s most popular “Bat” celebration held every August featuring 1.5 million Mexican free-tailed bats emerging from under the Congress Avenue Bridge.

Where Did They Come From?

If legend can be trusted, the Mexican Free-Tail bats started to frequent Austin, Texas, from spring to fall, at the same time the Congress Avenue Bridge was renovated, which attracted the bats already living in the drains located in the underbelly of the northern part of the bridge, seemingly by accident, and caused other bats of the same species to migrate from Mexico with the local bats making the same migration.  The bats were happy to find that the miniscule crevices under the bridge were ideal for building a colony and housing many, many bats.  With the assistance of time, purportedly, the colony eventually grew to be about one and half million strong, which is impressive, to say the least.

The bats population reached maximum capacity in approximately three years, stacking on top of one another in the aforementioned crevices.  This brought about the locals dubbing the northern portion of the bridge the “nursery”, which is where the mama bats leave their offspring as they go about their night-time insect hunting.  They then return to the nursery and use scent and echo location to find their bundles of nocturnal mammalian joy, which they then nurse before resting.

Having discovered Congress Bridge, the bats now make an annual migration from Mexico to Austin, Texas from the spring time to the fall, which would be the perfect time for any bat watchers or curious tourists to come visit the city and observe these marvelous mammals!

The Austin locals are also happy with the environmentally conscious bats whom eat an estimated thirty thousand pounds of insects every single night, reducing the need for any pesticide usage.  Not to mention that those pesky mosquitoes virtually do not exist due to the hungry creatures eating them every night.

About the Bats

When the bats initially migrate back to Austin, Texas, there will approximately be about 750,000 bats, which are, in their entirety, made up of pregnant females.  The colony, at this point is a “maternity colony”.  During their time as a maternity colony they will each birth one pup, generally creating an equal gender ratio within the colony, effectively doubling the colonies size to one and a half million!  That is a whole lot of bats!

Austin’s Congress Bridge Bats, about 1.5 million, the largest urban bat colony in the world, fly out from under the Congress Ave. Bridge each night from March to October every year.

The newborn pups will generally stay at the colony for the first season, or so, of their lives, but the mothers that birthed them can always be expected to return to where they birthed their offspring the year prior.  With all of the female bats in Austin, let us not forget about the bountiful male population, as well.  The male bats will generally cluster in small groups ranging from twenty to one hundred, often times being found roosting on building alcoves, and the like.

These aforementioned Mexican Free-Tailed bats can live almost a decade and can weigh approximately twelve grams with a wingspan of eleven, or so, inches.  If they do not spread their wings, however, they are the size of an average adult’s palm.

Mexican free-tailed bats live for 8-9 years and only grow to weigh roughly 12 grams. Their wingspan is about 11”, but with their wings retracted, they can fit in the palm of a hand.

Another interesting fact about Austin’s bats are that in the early years of the 1980s, Austin locals worried about rabies infection and the implications therein of the bat populace outnumbering that of the local humans.  Purportedly, the locals petitioned for the extermination of the bats and the dismemberment of the colony.  If it were not for the Bat Conservation International organization, the bats may not have been around for the enjoyment of the individuals now.

If a bat ever contracts rabies, typically they have approximately seventy-two hours until they die, and are often experiencing the initial symptom of paralysis.  With that being said, if you see a grounded bat, do not touch it, as it may, in fact, have rabies.  If you happen to touch, or be bitten, by a downed bat, be sure to capture it and have it tested for rabies to ensure that you have not unknowingly contracted the disease.

Another bit of information that should be known is that, although the Mexican Free-Tail bat is a powerful and agile flyer, the young bats tend to fly at a lower altitude and can have trouble with lifting off, causing them to fall into the water.  If a young bat is spotted in the water, simply leave it be, as it will attempt to “backstroke” to one of the bridge pylons and clamber to safety.

Where Can Someone See the Bats?

The Mexican Free-Tail bats can be found in quite a few places around Austin.  Not only are they seen in most of the caverns and caves dotting the countryside, but they can be seen just south of Austin, at Bracken Cave, at the Hancock Center, at McNeil Overpass and the I-35 bridge, and dotting the alcoves and sides of various buildings around the city.

Bat enthusiasts on top and below the Congress Avenue Bridge eagerly await the bat show when the bats drop out of the bridge for their nightly feeding.

The Statesmen Bat Observation Center, just southeast of Congress Bridge, does not cost much, and is available for public use.  With standing room along the top portion of the bridge and the closest parking to Congress Bridge, the Observation Center is definitely worth looking into if you want to see the bats.

If looking for bats by yourself does not seem too appealing, then you could always jump on one of the Austin Bat Tours, such as the Walking Tour, the Kayak Bat Sunset Tour on Lady Bird Lake, or the Bat Photo Tour.

Guide to Watching the Bats and Austin Bat Tours

With three different ways to experience the “Bats of Austin”, the bat tours will make for a memorable experience that will last a lifetime.

The Bat Walking Tour is approximately a ninety-minute tour guided by one of Austin’s leading bat experts.  Initially, the meeting point before the start of the tour is the Hyatt Hotel.  From there, the walk begins towards the Congress Bridge and stops at the Statesmen Observation Center where the bat experts then explain, in a thorough and vividly detailed manner, the history and backstory of Austin’s bats and how it all came about.

The Kayak Bat Watching Sunset Tour typically consists of a one hundred and twenty to one-hundred-and-fifty-minute endeavor that embarks from the Kayak Tour Offices on Riverside Drive and is an amazing way to view Austin up close and personal.  This tour encompasses some of Austin’s more historical and awe-inspiring sights, along with viewing the bats gobbling down bugs.

The Photo Tour is approximately a one-hundred-and-twenty-minute guided tour that begins at Congress Avenue Kayaks.  This tour is guided by a professional photographer who explains how to take amazing photographs of these majestic mammals.

One of the tips given on the Photo Tour is to shoot video instead of taking photos, as cellular devices typically do not have a fast-enough shutter speed to capture these agile animals in flight.

The various bat tours begin in the evening, and start in early March, proceeding until November.  Worst case scenario is that the bats do not take flight due to inclement weather, but the tours still afford many amazing photo opportunities.