The Bat of the 76: Real Nocturnal Wildlife

Who lives in the trees of the 76 when it gets dark?

If you have ever walked along Avenida 76 in Laureles when the sun hides behind the Unidad Deportiva Belén, you have surely seen something moving quickly among the treetops. They are not birds. Nor squirrels. They are bats. But not just any bats: we are talking about an entire colony that comes out punctually to hunt mosquitoes, moths, and gnats just as children return from school and adults sit on the terraces. In this neighborhood of Medellín, nocturnal wildlife is not in a zoo or a documentary: it is literally ten meters above your head.

Avenida 76 is one of the most tree-lined streets in Laureles. Its guayacanes, ceibas, and acacias form a biological corridor that connects the Parque de Laureles with the Unidad Deportiva Atanasio Girardot. And there, among the branches, lives a colony of insectivorous bats that many neighbors see every night but few know about. This article is for you, dad or mom taking your child to the park, and for you, biodiversity lover who knows that nature doesn't end at the botanical garden.

The species: the insectivorous bat of Laureles

Scientific name and characteristics

The bat you see coming out of the trees on the 76 probably belongs to the species Molossus molossus, locally known as the mastiff bat or common insectivorous bat. It is small: it measures between 8 and 10 centimeters long, with a wingspan of about 30 centimeters. Its fur is dark brown, almost black, and its face has a short snout and rounded ears. Don't be scared: it is not hematophagous (it doesn't suck blood). Its diet consists almost exclusively of flying insects.

A typical colony in Laureles can have between 50 and 200 individuals. They come out at dusk, between 6:30 p.m. and 7:30 p.m., depending on the season. In July 2026, with longer days, the emergence occurs around 7:15 p.m. They fly in fast, erratic circles, sometimes brushing the treetops, sometimes descending to the height of the traffic lights.

Local diet: what do they eat on the 76?

These bats are pest control machines. Each individual can eat between 500 and 1,000 mosquitoes per night. In a colony of 100 bats, that means up to 100,000 mosquitoes eliminated every night. In an area like Laureles, where there are many parks and green areas, this is a direct benefit for families who use outdoor public spaces. Fewer gnats mean fewer bites, fewer diseases like dengue, and less need for chemical repellents.

In addition to mosquitoes, they hunt moths, midges, and small flying beetles. The insects attracted by the lights of the lampposts and terraces are their favorite buffet. That's why you see them flying near the lamps on the 76, right where we humans sit to have coffee.

Habitat: the specific trees of the 76

Where exactly?

The most visible colony is located on the stretch of Avenida 76 between Carrera 70 and Carrera 74, specifically in the yellow guayacán (Handroanthus chrysanthus) and ceiba pentandra (Ceiba pentandra) trees that are in front of the Laureles II residential complex and the Clínica del Prado. There are also frequent sightings in the Australian blackwood (Acacia melanoxylon) trees located in the small square of the Parque de Laureles, right next to the Nuestra Señora del Rosario church.

These trees have ideal characteristics for bats: rough bark to hang from, dense branches that provide protection during the day, and sufficient height (between 12 and 20 meters) to escape predators like owls or cats. During the day, the bats remain hidden in bark crevices or natural hollows in the trunk. You won't see them unless you know where to look.

Why these trees?

The guayacanes and ceibas on the 76 have a key characteristic: they produce flowers and fruits that attract insects. The ceibas, for example, have large flowers that open at dusk and emit a sweet smell that attracts moths. The bats know there is food there. Additionally, the branch structure allows the bats to hang in tight groups, which helps them maintain body heat during the cool nights in Medellín, which in July hover around 16°C.

Another factor is lighting. The lampposts on the 76 are sodium, which emit a yellow light that attracts flying insects. The bats have learned that these lampposts are like all-you-can-eat restaurants. That's why you see their silhouettes cut out against the light as they fly in zigzags.

Observation guide for families

Ideal time: 7:30 p.m.

The most productive observation window is between 7:15 p.m. and 8:00 p.m. In July 2026, sunset in Medellín occurs around 6:20 p.m., but the bats wait until the light is low enough to feel safe. They emerge in waves: first a few scouts, then the main group, and finally the stragglers. The peak of activity is at 7:30 p.m., when the sky is dark but there is still enough residual light to see their silhouettes.

What to bring

• Red flashlight: white light dazzles and scares them away. A flashlight with a red filter (or a piece of red cellophane over the flashlight) does not bother them and allows you to see them without startling them.
• Binoculars: not necessary to see them fly, but useful for observing details like their erratic flight or their landings on branches. 8x42 binoculars are ideal.
• Dark clothing: bats have good night vision, but light colors can alert them. Wear a dark shirt and pants to go unnoticed.
• Folding chair or blanket: you will be standing or sitting for about 30 minutes. Bring something comfortable to sit on the sidewalk or on the grass of the Parque de Laureles.
• Notebook and pencil: children can draw the silhouettes or count how many bats they see. It is an educational activity that turns the outing into a citizen science game.

How not to scare them away

• Don't shout or run: bats are startled by sudden movements and loud noises. Speak softly.
• Don't use a white flashlight: we already said it, but it's key. White light disorients them and can cause them to crash into objects.
• Don't touch the trees: if you see a bat hanging on a low branch, do not try to touch it or get closer than two meters. They can bite if they feel threatened (although they are not aggressive).
• Don't use insect repellent: strong chemicals can irritate their respiratory systems. If you are going to observe, avoid applying repellent in the area.

Fun fact: the invisible benefit for Laureles

Did you know that the bat colony on the 76 eliminates approximately 1.5 million mosquitoes per month? That's more than 18 million insects per year. In a city like Medellín, where dengue is a recurring problem, these bats are silent allies of public health. A 2023 study by the University of Antioquia estimated that urban colonies of Molossus molossus reduce the mosquito population by up to 30% within a 500-meter radius of their roosts. This means that families living in the towers on the 76, in the surrounding residential complexes, have fewer gnats on their terraces and balconies thanks to these animals.

Another fun fact: the bats of Laureles don't just eat mosquitoes. They also hunt moths that attack the guayacán trees. Moths lay eggs on the leaves, and the larvae damage the trees. By eating the adult moths, the bats protect the urban tree canopy. It's a perfect ecological cycle: healthy trees attract more insects, insects feed the bats, and the bats maintain the balance.

How to protect them: what neighbors can do

Don't fumigate at night

Many residential complexes and the Medellín City Council carry out mosquito fumigations. If done between 6 p.m. and 10 p.m., the chemicals directly affect the bats, which are flying and breathing at that very moment. Insecticides like permethrin can cause neurological damage and even death. Recommendation: if you are a building manager or president of the community action board, request that fumigations be done between 10 a.m. and 2 p.m., when the bats are resting in their shelters and the insecticides have less impact on them.

Don't cut down the roosting trees

The guayacán and ceiba trees on the 76 are the habitat of this colony. If they are cut down, the bats have nowhere to take shelter and are forced to look for other, often less safe, sites. If you see that any of these trees are going to be pruned or felled, you can contact the Medellín Ministry of the Environment (line 123 or through the City Hall website) to report that it is a tree with a bat colony. Pruning should be done during the day and under the supervision of a biologist.

Install bat boxes

If you want to help even more, you can install bat boxes in the trees on your block. These wooden boxes, similar to birdhouses but with a smaller entrance, offer them a safe place to rest during the day. They can be found at nurseries in Medellín or can be built with untreated wood. Place them at a