Tree swallow in flight. Extremely agile flyers, swallow populations all over the world are in decline. Reasons include, insecticides, loss of habitat, and now anthropogenic noise can be considered as a factor
Photo Credit: Ricki Hurst

How noise can harm bird survival


Most people may not realize it but audio communication is vital for young birds to survive. Researchers in east coast Nova Scotia found that ambient noise can disrupt communication between adults and nestlings, putting the nestlings at risk

Andy Horn is a research adjunct at the Leonard Lab at Dalhousie University

Andrew Horn Research Adjunct at the Leonard Lab, Dalhousie University, Halifax N.S. © Ricki Hurst

Baby birds, unable to fly, depend on their parents for food and protection. It is the vocal communication between them that signals both feeding and when they should crouch and keep quiet for protection from predators seeking to locate the nest.

The researchers found that ambient noise can disrupt that communication. This leaves the nestlings vulnerable to hunger and weakness, or to attracting predators.

4-5 tree swallow nestlings huddle down trying to hide in a defensive response to the opening of the nest to sunlight during the study in the Annapolis valley of Nova Scotia. This would be the reaction crouch and stay still upon hearing a parent’s warming call. © Ricki Hurst

Led by Andrew Horn, the researchers suspected that the exaggerated begging calls may be more than just a display for attention but rather a needed expression to overcome background noise, natural or not,  even though the parent and nestlings are in such close proximity.

By playing white noise at a fairly low level, the researchers found that typical audible signals were being missed in a noticeable percentage of cases.

This also included for example, warning calls by parents.

One of the swallow nest boxes. White noise played at a relatively low level of 65dB was found to disturb communication signals between adult and nestling. © Ricki Hurst

Normally a warning call would cause the nestlings to crouch and remain still in the nest whereas failure to hear the warning  may leave the chicks still moving and chirping, enabling the predator, crow or racoon for example,  to focus in on the sound and movement and find the nest.

Horn says that habitat loss is certainly a major reason for bird population decline.  While the researchers were studying swallows in this case, Horn says the noise and communication issue is very likely the same for all species of birds

He adds however that the noise from human activities, such as traffic, construction,  forestry, etc, can easily be seen as an additional source of stress on birds already being affected negatively by several other stressors and as such, another contributor to their declining numbers.

Although not all ambient noise comes from human activity, a busy highway or a new housing development is a more persistent source of noise than intermittent natural phenomena like wind and rain, Horn said

While “white noise” was used in this phase of the research, Horn says they will continue to study the effects of more specific man-made sounds.

Categories: Environment, International, Internet, Science and Technology
Tags: , , ,

Do you want to report an error or a typo? Click here!

@*@ Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

 characters available

Note: By submitting your comments, you acknowledge that Radio Canada International has the right to reproduce, broadcast and publicize those comments or any part thereof in any manner whatsoever. Radio Canada International does not endorse any of the views posted. Your comments will be pre-moderated and published if they meet netiquette guidelines.

Netiquette »

When you express your personal opinion in an online forum, you must be as courteous as if you were speaking with someone face-to-face. Insults and personal attacks will not be tolerated. To disagree with an opinion, an idea or an event is one thing, but to show disrespect for other people is quite another. Great minds don’t always think alike—and that’s precisely what makes online dialogue so interesting and valuable.

Netiquette is the set of rules of conduct governing how you should behave when communicating via the Internet. Before you post a message to a blog or forum, it’s important to read and understand these rules. Otherwise, you may be banned from posting.

  1.’s online forums are not anonymous. Users must register, and give their full name and place of residence, which are displayed alongside each of their comments. reserves the right not to publish comments if there is any doubt as to the identity of their author.
  2. Assuming the identity of another person with intent to mislead or cause harm is a serious infraction that may result in the offender being banned.
  3.’s online forums are open to everyone, without regard to age, ethnic origin, religion, gender or sexual orientation.
  4. Comments that are defamatory, hateful, racist, xenophobic, sexist, or that disparage an ethnic origin, religious affiliation or age group will not be published.
  5. In online speak, writing in ALL CAPS is considered yelling, and may be interpreted as aggressive behaviour, which is unpleasant for the people reading. Any message containing one or more words in all caps (except for initialisms and acronyms) will be rejected, as will any message containing one or more words in bold, italic or underlined characters.
  6. Use of vulgar, obscene or objectionable language is prohibited. Forums are public places and your comments could offend some users. People who use inappropriate language will be banned.
  7. Mutual respect is essential among users. Insulting, threatening or harassing another user is prohibited. You can express your disagreement with an idea without attacking anyone.
  8. Exchanging arguments and opposing views is a key component of healthy debate, but it should not turn into a dialogue or private discussion between two users who address each other without regard for the other participants. Messages of this type will not be posted.
  9. Radio Canada International publishes contents in five languages. The language used in the forums has to be the same as the contents we publish or in one of the two official languages, English or French. The usage of other languages, with the exception of some words, is forbidden. Messages that are off-topic will not be published.
  10. Making repetitive posts disrupts the flow of discussions and will not be tolerated.
  11. Adding images or any other type of file to comments is forbidden. Including hyperlinks to other websites is allowed, as long as they comply with netiquette. Radio Canada International  is in no way responsible for the content of such sites, however.
  12. Copying and pasting text written by someone else, even if you credit the author, is unacceptable if that text makes up the majority of your comment.
  13. Posting any type of advertising or call to action, in any form, to Radio Canada International  forums is prohibited.
  14. All comments and other types of content are moderated before publication. Radio Canada International  reserves the right to refuse any comment for publication.
  15. Radio Canada International  reserves the right to close a forum at any time, without notice.
  16. Radio Canada International  reserves the right to amend this code of conduct (netiquette) at any time, without notice.
  17. By participating in its online forums, you allow Radio Canada International to publish your comments on the web for an indefinite time. This also implies that these messages will be indexed by Internet search engines.
  18. Radio Canada International has no obligation to remove your messages from the web if one day you request it. We invite you to carefully consider your comments and the consequences of their posting.