Industrial noises have a harmful effect on birds. Researchers at the University of Colorado liken the effects to those similar to people with Post Traumatic Stress Disorder.

According to CU research, birds exposed to constant noise from oil and gas operations show physiological signs of chronic stress, and in some cases, have chicks whose growth is stunted.

For the study, the researchers followed several breeds of birds, including mountain blue birds, which breed near oil and gas operations on BLM property in New Mexico.

They monitored things like hatching success, body size and feather length.

The birds nesting in areas with more noise had lower baseline levels of a key stress hormone. Researchers say that doesn't mean they're not stressed, it's the opposite.

When comparing with research of humans and rodents with PTSD, stress hormones are chronically low.

Nathan Kleist, the lead author on the study, says the response from the birds was similar to a human who is under chronic psychological stress. Kleist says those stress hormone levels paired with the reproductive and growth problems in some of the birds helped his team come to the conclusion that the stress is constant, just like the added noise.

Researchers say the reasoning is this: when the fight-or-flight response is constantly revved, the body sometimes adapts to save energy and can become sensitized. The birds in the study are in a state of constant stress because their environment is noisy and they can't hear what's happening around them.

In a release from the University of Colorado, Kleist said “In what we consider to be the most integrated study of the effects of noise pollution on birds to date, we found that it can significantly impact both their stress hormones and their fitness.”

“Surprisingly, we also found that the species we assumed to be most tolerant to noise had the most negative effects.”

Kleist says the noise from oil and gas sites on the BLM property in New Mexico changes the acoustic environment, and by changing the acoustic environment, it can change the animals that live there.

Kleist says birds are extra susceptible to the environment because they are highly vocal and are listening to predators at all times.

Kleist says he hopes his research helps people in the future to consider noise when creating conservation plans.