For humans, getting a message across to other people can sometimes be a challenge when noise from background sources drowns out and hampers effective communication. The same goes for bluebirds that sometimes find their majestic songs muffled by traffic and other sounds produced by human activity.
In a study published in the journal Integrative & Comparative Biology, researchers from the University of Exeter in the United Kingdom examined how male bluebirds alter their songs to counteract the effects of noises in their surroundings.
They discovered that these natural crooners make real-time adjustments to their singing in response to increasing levels of background noises, producing lower-pitched but louder songs. The findings suggest that birds are capable of noticing increases in noises and reacting accordingly, much like people do when in raucous environments.
Behavioral ecologist and lead researcher Dr. Caitlin Kight said that the findings could help provide scientists with better understanding regarding the various environmental constraints that hinder communication among animals.
She said that these results could also enhance people's own awareness of what type of human activities affect animals in order to find out how these disturbances could be lessened.
Kight explained that while several manmade noises often vary from noises found in nature, certain similarities can still be found between the two sources, such as their pitch, volume, or timing.
She mentioned that noise, such as those produced by traffic, may not be significantly different from noise produced by heavy winds or waterfalls.
Kight pointed out animals that developed in habitats with natural features could potentially have the ability to respond to noises already included in their repertoires of behaviors. She said that this can certainly be observed among bluebirds.
Earlier studies have shown that birds sing differently depending on whether they are in a quiet area or in a noisy environment, but it was not clear if the animals were capable of making adjustments to their voices in real time. This pertains to the ability to make necessary shifts in response to noise increases such as those made by passing cars.
Now, five species of birds have been found to make real-time modifications to their singing depending on the level of background noise. The Exeter study is the first of its kind to describe this ability among birds of the thrush family.
For this research, Kight recorded the songs of 32 different male bluebirds and studied two songs from each of them. She investigated whether these male bluebirds changed their songs between the loudest and quietest period of ambient noise.
Kight discovered that the male bluebirds produced songs that were lower-pitched and louder as the noise in their background increased. This shows that the animals are capable of both perceiving and immediately responding to increases in background noise, enabling the birds to produce songs that could be heard better by prospective mates or even their rivals.
Photo: Colby Stopa | Flickr