Stress may lead to better bird parenting

June 14, 2011
This is a tree swallow at the Queen's University Biological Station (QUBS). Credit: P-G Bentz

Birds with high levels of stress hormones have the highest mating success and offer better parental care to their brood, according to new biology research at Queen's University.

"Having high levels of glucocorticoid or stress hormone is often thought to indicate an individual in poor condition who has a low level of mating success. However, our research indicates that tree swallows with the highest levels of stress hormone have the highest ," says Frances Bonier (Biology) who investigates the way animals cope with challenges in their environment.

The researchers measured glucocorticoid levels in female tree swallows before and after experimentally changing their brood sizes. Females whose broods were enlarged by two nearly doubled their glucocorticoid levels, while the glucocorticoid levels of females whose broods were reduced remained unchanged.

Females with greater increases in glucocorticoids also fed their nestlings at higher rates, suggesting that facilitate parental behaviour.

In previous years, the researchers found correlations between , the number of offspring in a brood, and the amount of weight nestlings gained. The next stage is manipulating levels of stress hormones in tree swallows and observing subsequent effects on parental behaviour.

For all these studies, the focal system is a breeding population of tree swallows established more than 35 years ago at the Queen's University Biological Station (QUBS).

"The QUBS population of tree swallows offers a unique opportunity to conduct large-scale , allowing us to tease apart the complex interactions between the environment, physiology, behaviour, life history and fitness effects in free-ranging animals," says Dr. Bonier.

QUBS has been a pivotal part of research and teaching at Queen's for more than six decades and hosts researchers from both Canadian and international institutions. Research at QUBS has resulted in more than 800 publications in peer-reviewed journals and more than 200 graduate and undergraduate theses.

Dr. Bonier's research will be published in an upcoming issue of Biology Letters.

Explore further: Mourning baboons seek comfort from friends

Related Stories

'Nervous' birds take more risks

October 26, 2007

Scientists have shown that birds with higher stress levels adopt bolder behaviour than their normally more relaxed peers in stressful situations. A University of Exeter research team studied zebra finches, which had been ...

Do hormones dictate breeding success in birds?

January 25, 2011

( -- Some animals produce more offspring than others do. Hormones like prolactin and corticosterone can exercise a crucial influence on the behaviour of birds in the breeding season and therefore on their reproductive ...

Recommended for you

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Ancestral background can be determined by fingerprints

September 28, 2015

A proof-of-concept study finds that it is possible to identify an individual's ancestral background based on his or her fingerprint characteristics – a discovery with significant applications for law enforcement and anthropological ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.