Birds could hold secret to lasting relationships

The more offspring a couple raise the more closely together they work to feed them, contradicting years of scientific belief, new Deakin research has found.

While the new findings relate to birds, Alfred Deakin Postdoctoral Research Fellow Dr Mylene Mariette says the research would also apply to any species with long-lasting relationship, which may include humans. 

Dr Mariette said research of parental behaviours within the avian population had largely focused on conflict of interest since the 1970s when scientists had discovered that when it comes to feed the nestlings, birds often exploit their partner’s efforts in order to reduce their own workload.

“This study demonstrates that conflict does not always dictate parents’ interactions, as partner coordination can outperform partner exploitation,” Dr Mariette said. 

Dr Mariette, a researcher from Deakin’s Centre for Integrative Ecology, within the School of Life and Environmental Sciences, completed the research as part of her PhD under supervision from Professor Simon Griffith at Macquarie University.

The work focussed on the Australian zebra finch (Taeniopygia guttata), which pairs for life and is very faithful. The study, 'The Adaptive Significance of Provisioning and Foraging Coordination Between Breeding Partners', is published in 'The American Naturalist', one of the world's premier peer-reviewed ecology, evolution, and behaviour research journals.

“Although this species is widely studied in captivity across the world, this work takes place in the zebra finches’ native land, the Australian arid zone” Dr Mariette said.

“We used microchip tags to record all visits by birds to their nests and temporary feeders scattered in the desert. This system allowed us to determine the level of coordination between partners as they raised their young.

“We increased or decreased the number of nestlings in the nest to force parents to either work harder or less than they initially planned to.

“But rather than being more selfish when forced to work harder, partners actually increased their level of coordination with each other.

“In addition, nestlings grew better when raised by highly coordinated parents. This is the best evidence to date that partners’ coordination can improve parental care efficiency, and that pairs do resort to this strategy in hard times.

“This finding suggests that more work should focus on cooperative aspects of pair bonds rather than just the conflicts between partners.”

Dr Mariette predicts that according to theoretical models, such benefits are more likely to operate in species where partners stay together for a long time, either to have multiple broods together or because the period of parental care is very extended, such as in humans. 

“This study demonstrates that acting cooperatively with one?s partner is a successful strategy, but whether humans are prepared to follow the theory is another story,” Dr Mariette said.