Why fireworks can be a death sentence for wildlife

On January 1, 2025, a hiker encountered a terrifying scene in Bulgaria’s Sredna Gora mountain range. Hundreds of dead birds—most of them juveniles—were scattered in small groups on a snowy hiking trail. Necropsies later discovered wounds, bruises, missing feathers, internal bleeding, and broken wings. 

The next month, scientists attributed the mass die-off to a fireworks display in a nearby town the night before. It’s thought that the birds, scared by noise, fled and flew into objects such as trees or collided with other birds. 

While many experts say these types of events are likely common, they’re not well-documented. That’s because rehabbers who take care of wild animals usually aren’t there to witness the link between the injury or death and the fireworks, says Stephany Lewis, director of the Wildlife Medical Clinic at the University of Illinois College of Veterinary Medicine in Urbana. “I think it likely happens more often, but the animals may never be found or the mortality event is not attributed to fireworks,” she notes. 

In fact, experts say that the panic and disorientation that wildlife experience due to fireworks displays often result in traumatic injuries and even death. These loud explosions can lead to abandonment of their young and stress-induced disorders. 

Dazed and disoriented

It’s well-known that many dogs fear fireworks and that shelters take in more animals the day after the Fourth of July due to pets who run away after becoming scared of the noise. However, rehabbers who take care of wild animals also see more patients around the summer holiday, especially at clinics with higher annual caseloads, Lewis says. “Any traumatic injury we see the morning of July 5, we are always very suspicious of [fireworks] being the cause unless another traumatic event was witnessed by the finder of the animal,” she says

Much of the research to date focuses on the effects of fireworks on birds. 

One 2022 paper correlated New Year’s Eve fireworks with a “substantial stress response” in greylag geese, whose heart rates and body temperatures significantly increased. This physiological response is “costly,” researchers say, as it limits the amount of energy these animals can consume and use.

And in 2025, researchers in Berlin reported behavioral changes—including erratic flight patterns at midnight and not using the usual roosting trees—in several corvid species in response to New Year’s fireworks. Another study in the Netherlands found that birds fled “en mass” in response to these loud explosions.

Such frantic reactions can end in tragedy, according to experts. Fireworks startle birds, Lewis says, especially when they’re settling down to sleep, rest, or perch, a behavior known as roosting.

“They will panic and fly and often hit windows, buildings, [and] trees,” she says. The collisions can lead to serious injuries and even death.

Fireworks’ explosive sounds can be especially bothersome to birds with sharp hearing, such as owls, says Anna Tobin, ambassador animal program director at the New Mexico Wildlife Center in Española. Fireworks on the Fourth of July are extra problematic, she adds, as the holiday often falls within mid- to late-fledgling season, a time when young, fully feathered birds leave the nest and learn how to fly. Though this is a natural part of their development, fireworks add another stressor to the mix. 

An instinct to flee

While less studied than birds, other wild animals aren’t immune from the stress of fireworks. Prey species such as rabbits and deer are likely to instinctively flee what they perceive to be danger, such as loud noises, Lewis says. “Especially if it's dark out, that's when they can run into a fence or otherwise get themselves into trouble,” she adds. 

Disorientation from these blasts can lead animal parents to abandon offspring too. This can be devastating for animals with low reproduction rates, such as North American porcupines, which have up to two babies called porcupettes per year, Tobin notes.

“They stay with mom for a year, but if mom gets scared by the fireworks, [she’ll] run away, and then it's going to take another year for her to be able to reproduce,” Tobin says. Abandoned young can easily die from starvation or predation.

Summer fireworks often fall during or right after baby season, when many reptiles and mammals are coming of age and learning how to be wild. “A lot of animals are starting to do things on their own for the first time and making a lot of mistakes along the way,” says Tobin, whose facility sees a lot of patients during this time of year. Fireworks cause additional stress during this time, which can lead to developmental problems like stunted growth and anxiety-driven injuries such as collisions with hard objects.

A mixed impact 

Many studies about fireworks’ effects on animals indicate brief disturbances. A team in Cape Town, South Africa, for instance, observed acute but short-term displacement of seals and gulls but no measurable long-term impacts. The researchers noted that they found little underwater sound impact and that collective research suggests that fireworks are more impactful to land-dwelling species.

Recently, researchers documented a marked decline in hunting among big brown bats at California’s Monterey Bay Marine Sanctuary during an annual fireworks display. The bats, which snatch moths from the water’s surface, returned to eating after the 30-minute show ended.

“No prey was caught during those fireworks,” says Kerri Seger, a bioacoustician with U.S.-based Integral Consulting, who used acoustics to identify the “feeding buzz,” a rapid burst of echolocation calls that these animals emit while hunting. Her data indicated that the bats resumed catching prey 13 minutes after the finale. 

That is a “pretty good recovery time,” according to Seger. However, this doesn’t rule out the possibility of cumulative stress, says bat expert Joy O’Keefe, an associate professor of natural resources and environmental sciences and a wildlife extension specialist at the University of Illinois Urbana–Champaign.

“That accumulation of cortisol that will happen when an individual is stressed, whether it be a human or another animal, can be detrimental to our immune function and then also create long-term problems,” O’Keefe says. 

For one, repeated stress can lead to a condition called capture myopathy, Lewis says. This physiological or pathological response to extreme stress, which is generally associated with wild animals that have been captured by humans, can lead to severe muscle necrosis and organ damage. 

A world without fireworks? 

Cities such as Salt Lake City and Boulder, Colorado, have replaced fireworks displays with drone shows over the past few years. These choreographed aerial displays often showcase hundreds of drones equipped with LED lights, which fly in unison, creating massive 3D imagery set to music.

Drone displays reduce noise and pollution, and they eliminate wildfire risk. “The only trade-off I see is drones also emit high-frequency noise,” Seger says, explaining that while these devices produce a much narrower range of sound frequencies, they could still be bothersome to some species, such as seagulls, whose most sensitive hearing range perfectly overlaps with the frequency of the drone.

“Our dog hates drones,” she adds. “…They have a real high-pitched squeal that I think dogs can hear but we can't hear.” 

Lewis doesn’t think humans will forego fireworks completely, but she encourages people to avoid setting them off anywhere near forests, wetlands, nesting grounds, state or national parks, and nature preserves. She says people should also avoid breeding grounds, particularly from early spring through late summer. 

“I would say the absolute minimum distance from those sites is one mile,” Lewis says. “Certain species—in particular seabirds and shorebirds—have large known and very visible nesting sites…. I think it's very important just being considerate to all of our wild neighbors.”