PTSD in birds: Living with noise pollution gives them chronic stress, hypervigilance, anxiety

Can animals show symptoms just like humans do when suffering from conditions such as post-traumatic stress disorder (PTSD)? It’s more likely than you think.

As it turns out, birds can be under so much stress that they start to exhibit signs of PTSD, even if only temporarily. This is according to a study conducted by a group of researchers who wanted to know how much noise pollution can affect a local bird population.

The study titled, “Chronic anthropogenic noise disrupts glucocorticoid signaling and has multiple effects on fitness in an avian community,” takes a closer look at what happens with birds when they are subjected to constant amounts of stress-inducing environmental noise. The researchers found their main motivation to conduct the study by looking at previous research, which they deemed unreliable and “often produce contradictory or inconclusive results.”

In their own research attempt, they were able to learn that birds can be “chronically stressed” due to noise pollution, and worse, young chicks that are exposed to the same noise levels are less likely to survive.

According to Rob Guralnick, an associate curator of biodiversity informatics at the Florida Museum of Natural History and co-author on the study, the birds suffer from PTSD-like symptoms because they are sort of trapped and unable to get away from the source of their stress. “These birds can’t escape this noise. It’s persistent, and it completely screws up their ability to get cues from the environment,” said Guralnick.

If the birds could just figure out what’s going on around them and what the source of the noise is, Guralnick says, perhaps they would feel better. But since they are just left dazed and confused, they can’t help but just deal with the stress, eventually showing signs of PTSD.

“Just as constant stress tends to degrade many aspects of a person’s health, this ultimately has a whole cascade of effects on their physiological health and fitness,” Guralnick added.

In birds, just as in humans, there is a hormone called corticosterone. The researchers noted that whenever their living environment was noisier, levels of this hormone tended to decrease. It is said that an unusually low concentration of corticosterone is often a sign that an animal is under such a large amount of stress that the body ends up self-regulating and reducing production of it as a manner of self-protection. In short, in trying to make sure that they don’t hurt themselves due to too much stress, their stress hormone levels go down on their own.

That’s mainly how the researchers could tell that the birds were experiencing the negative effects of noise pollution in their homes. Based on data gathered from their study, the researchers were able to conclude that noise pollution can indirectly reduce animal habitat and at the same time, directly influence animal fitness and ultimately, their numbers. For instance, the disruptive noise acts as an audio buffer, which¬†affects the ability of the birds to detect potential predators. This is according to Nathan Kleist, then a doctoral student from the University of Colorado¬†Boulder. Kleist was the one that led the researchers in setting up 240 nesting boxes positioned near the noisy gas compressors used in the study.

The researchers further noted that a seemingly simple 10-decibel increase in noise above what is deemed the natural level can lead to a reduction of animal habitats by up to 90 percent. So not only will the animals be under huge amounts of stress from the noise, they will also be facing problems due to losing their homes.

With this knowledge, the researchers hope to one day contribute to efforts in preserving the lives of these animal species as well as to the conservation of the environment.

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