Stress after birth makes songbird independent

22 July 2015

Behavioural biologist Neeltje Boogert has demonstrated that differences in social behaviour in zebra finches are partly determined by early-life exposure to stress hormones. Stressed birds were found to be far more independent in their later life than their non-stressed compatriots. The stressed birds learn from other birds and are less dependent on their parents. Boogert published the results in the journal Current Biology. She carried out her research at the University of St Andrews with funding from a Rubicon grant. Last week she was awarded a Veni grant by NWO.

Zebra finches on a new food puzzle. On the right, a young zebra finch female solves the puzzle grid, while on the left an adult male eats the reward: a leaf of spinach.Zebra finches on a new food puzzle. On the right, a young zebra finch female solves the puzzle grid, while on the left an adult male eats the reward: a leaf of spinach. een nieuwe voedselpuzzel. Rechts lost een jong zebravinkvrouwtje net de puzzel op, terwijl links een volwassen mannetje de prijs voor het oplossen opeet: een blaadje spinazie.

Boogert studied the highly social zebra finch during her research. She gave stress hormone (dissolved in peanut oil) to half of the chicks in 13 zebra finch nests, while the other half of the chicks received peanut oil without stress hormone. Boogert investigated how exposure to increased concentrations of stress hormone influenced the later social life of these zebra finches. For this she released the zebra finch families, together with other non-related birds, into large aviaries.

Superficial contacts

Boogert saw that the stressed birds spent less time in the vicinity of their parents. They were also less fussy about who they visited the feeding stations with. Consequently these stressed birds assumed a more central position in their social network. They made many social contacts but most of these were not enduring.

Their social learning behaviour also changed as a consequence of this. Boogert closed the standard feeding stations and observed how quickly the birds could solve a puzzle, which gave access to new food. The non-stressed chicks copied the behaviour of their parents to solve the puzzle. Stressed birds, however, learned from the non-related adult birds in the aviary. Furthermore, they also sought independently for the solution to the puzzle. They therefore solved the puzzle faster than their non-stressed compatriots.

Model animal

These findings demonstrate that social behaviour is not only determined by genetic characteristics, but that early-life, stressful experiences exert a large influence on the later social life of these birds. Songbirds are often used as a model animal for research into topics like the learning of human language. Furthermore, knowledge of social interactions between animals also helps us to understand how migratory birds learn migration routes from each other or how animals spread diseases.

In this research, Boogert also sees possible parallels with children who have traumatic early-life experiences and who later have more difficulty in building up close social relations.

Veni

Neeltje Boogert did her research at the University of St Andrews in Scotland with an NWO Rubicon grant, which allows young researchers to gain experience abroad. Initially she used the grant to focus on another research question. Last week she was awarded a Veni grant from NWO's Talent Scheme to continue her new line of research into the influence of stress factors on the later social life of birds.

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Source: NWO