'Nervous' birds take more risks

Oct 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 selectively bred to produce three distinct types – ‘laid-back’, ‘normal’ and ‘stressed’ – based on their levels of stress hormone.

The group was surprised to find that the ‘stressed’ birds were bolder and took more risks in a new environment than the group that was usually more laid-back. Their findings are published today (26 October) in the journal Hormones and Behaviour.

Like other animals including humans, birds respond to stress, created by the appearance of a predator or a change in their environment for example, by producing a hormone. In birds, this hormone is called ‘corticosterone’ and some individuals have higher levels of the hormone than others. The zebra finches in this experiment were bred to have three different corticosterone levels, with the ‘laid-back’ birds having lower levels than the ‘stressed’ birds.

The researchers put the birds into a new environment, which housed several unfamiliar objects, including new feeders. The ‘stressed’ birds were the first to visit the new feeders, which they also returned to more quickly than the other birds after being startled. Overall, they approached more objects than their normally more relaxed peers, showing greater risk-taking behaviour and arguably handling the situation better.

Dr Thais Martins of the University of Exeter said: “It initially seems counter-intuitive that birds with higher levels of the stress hormone showed bolder behaviour, normally associated with confidence. However, corticosterone is released to help tackle stress by encouraging the animal to adopt key survival behaviours like seeking food. So on reflection, perhaps it is not surprising that these birds are more likely to explore the environment and look for food.”

Previous research has indicated that animals show consistent individual differences in their behaviour when faced with certain challenges. Traditionally in this field of research, birds have been separated into two groups: ‘bold’ and ‘shy’, or ‘active’ and ‘passive’. These definitions are based on observations of their behavioural strategies, and the birds are then studied for physiological differences. This research took the opposite approach and separated the birds into groups by physiology, based on corticosterone production levels, and then looked for behavioural differences.

Source: University of Exeter

Explore further: France fights back Asian hornet invader

add to favorites email to friend print save as pdf

Related Stories

UMSL scholar examines evolution of learning

14 minutes ago

Why do monkeys learn to be afraid of snakes and not flowers? Is this knowledge the result of evolution by natural selection? Did the monkeys that couldn't learn that association quickly die and not reproduce?

Study details shortage of replication in education research

18 minutes ago

Although replicating important findings is essential for helping education research improve its usefulness to policymakers and practitioners, less than one percent of the articles published in the top education research journals ...

Samsung introduces Galaxy Alpha

24 minutes ago

Samsung Electronics unveiled its new design approach with the Galaxy Alpha. The latest addition to Samsung's Galaxy smartphone line, the Galaxy Alpha features a sophisticated design in a carefully constructed ...

People fake to look authentic on social media

26 minutes ago

Presenting an authentic image on social network sites (SNSs) includes an element of fakery according to a new study by researchers at Aalto University. During the study, researchers discovered that being authentic is very ...

Hoopoes' eggs show their true colors

27 minutes ago

Hoopoe females use cosmetics on their eggs - and the eggs gradually change color when they are incubated, from bluish-grey to a more saturated greenish-brown. This happens because secretion from the uropygial or preen gland ...

NERSC launches next-generation code optimization effort

27 minutes ago

With the promise of exascale supercomputers looming on the horizon, much of the roadmap is dotted with questions about hardware design and how to make these systems energy efficient enough so that centers can afford to run ...

Recommended for you

France fights back Asian hornet invader

34 minutes ago

They slipped into southwest France 10 years ago in a pottery shipment from China and have since invaded more than half the country, which is fighting back with drones, poisoned rods and even chickens.

Tide turns for shark fin in China

44 minutes ago

A sprawling market floor in Guangzhou was once a prime location for shark fin, one of China's most expensive delicacies. But now it lies deserted, thanks to a ban from official banquet tables and a celebrity-driven ...

New research reveals clock ticking for fruit flies

53 minutes ago

The army of pesky Queensland fruit flies that annually inflict many millions of dollars-worth of damage on the nation's horticultural industry may be about to see their numbers take a significant dive thanks ...

The ABC's of animal speech: Not so random after all

2 hours ago

The calls of many animals, from whales to wolves, might contain more language-like structure than previously thought, according to study that raises new questions about the evolutionary origins of human language.

Manatees could lose their endangered species status

13 hours ago

About 2,500 manatees have perished in Florida over the last four years, heightening tension between conservationists and property owners as federal officials prepare to decide whether to down-list the creature to threatened ...

User comments : 0