Baby Birds May Struggle to Survive with Noise Pollution

It turns out that nestlings, baby birds, could be suffering from noisy environments. Because nestlings depend on their parents for both food and protection, vocal communication is key-something that could be drowned out if the surroundings are too loud.

In order to see how ambient noise might impact nestlings and their survival, the researchers presented nestling tree swallows with audio recordings of a parent warning of a predator or announcing a food deliver. Then, the scientists compared the responses that the baby birds had to the sounds when played with recorded background noise or in a quiet environment.

Faced with competition from hungry siblings, nestlings instinctively react quickly to any sign that a parent might have food, vigorously begging to attract attention. Yet this same begging puts them at risk of misidentifying predators as parents.

In the end, the researchers found that the background noise reduced the nestlings' responsiveness to both feeding calls and alarm calls. They often failed to beg after hearing a feeding call and also failed to fall silent when hearing a warning call. Not only that, but they received little assistance from parents, who did not appear to change their calls in noisier situations.

"This idea had been neglected, perhaps because parents and nestlings are so close to each other when they communicate that you think error wouldn't be an issue," said Andy Horn, one of the researchers, in a news release. "We usually associate declines in animal populations with our physical destruction of habitat, but the noise we make is another threat that we can't ignore."

The findings reveal the background noise could be impacting bird populations. This, in turn, highlights the need to reduce noise pollution in certain areas, especially when it comes to conservation efforts.

The findings will be presented at the 168^th Meeting to the Acoustical Society of America (ASA).