Residents and tourists are gathering each night near Congress Street Bridge in downtown Austin, Texas, to watch some 1.5 million bats form a black cloud so large that it shows up on local weather radar, Reuters reported.

The bats have been finding habitat under the bridge since the 1980s when they moved to Austin looking for food, according to experts.

Central Texas is the world’s largest habitat for bats with over 100 million of them residing here. These bats living below the bridge in Austin apparently form the largest urban bat colony in the world.

A recent drought in Texas has destroyed crops in Texas and killed delicious pests that the Mexican free-tailed bats eat. This has forced bats to make their nightly flight for food earlier than usual each night, giving the locals more time to watch the normally-nocturnal critters fly before the sun goes down.

Start the slideshow to view the nocturnal creatures in Austin.

A Bat Frenzy Austin
Spectators gather by the water near the Congress Street bridge in downtown Austin, Texas July 27, 2011, to watch the bats make their nightly flight for food. The largest urban bat colony in the world lives below a bridge in Austin. REUTERS
A Bat Frenzy Austin
Some of 1.5 million bats move through the sky near downtown Austin, Texas July 26, 2011, as they do every night in the summer, looking for food. Each night they stream from under a bridge by the hundreds of thousands in a black cloud so large that it shows up on local weather radar. REUTERS
A Bat Frenzy Austin
Some of 1.5 million bats emerge from below the Congress Street Bridge near downtown Austin, Texas July 27, 2011. A drought in Texas has forced bats leave home earlier than usual each night to find nourishment. REUTERS
A Bat Frenzy Austin
Spectators line up on the Congress Street Bridge in downtown Austin, Texas on July 26, 2011, to watch the bats make their nightly flight for food. A drought in Texas has forced bats leave home earlier than usual each night to find nourishment, giving the locals more time to watch the normally-nocturnal critters fly before the sun goes down. REUTERS
Vampire Bats
New research shows that vampire bats, who solely feast on the blood of mammals, have evolved heat sensors in their face in order to detect blood with precision, a mystery left undiscovered until now. REUTERS
A Bat Frenzy Austin
Spectators sit by the water near the Congress Street bridge in downtown Austin, Texas July 26, 2011, to watch the bats make their nightly flight for food. REUTERS