Impact story

Tweeting zebra finches in the Australian outback

The zebra finch is one of the most widely studied songbirds in a laboratory setting, but little is known about its ecology and behaviour in the wild. This is now changing thanks to the Behavioural Ecology chair group: the behavioural ecologists want to know how zebra finches communicate, make breeding decisions and thereby cope with the changing conditions of the Australian outback.

The habitat of the Australian zebra finch changes constantly. In the outback, it can be incredibly dry and hot for months or even years on end, with temperatures exceeding 40 degrees. These droughts may be followed by periods of heavy rain, when the grass will grow incredibly fast. “It has been extremely dry in the Australian outback in recent years,” says behavioural ecologist Marc Naguib. “Many animals such as emus, goats and kangaroos have died, but zebra finches have been able to adapt to the extreme conditions quite well. They pant to cool themselves and apparently find enough grass seeds buried in the ground from earlier good times. However, we do see that they stop breeding when it is so extremely hot and dry for such a long time.”

Marc Naguib and his colleagues Hugo Loning (PhD candidate) and Simon Griffith (Macquarie University, Sydney) are studying how zebra finches cope with unpredictable conditions and how they communicate when making breeding decisions. “Pairs of zebra finches breed in groups and make all kinds of decisions about breeding, such as when to start, when to stop and when to start again,” says Naguib. “The birds in the study population breed mainly in October and November, but if conditions are right – for example if there is enough food – they can breed all year round. We are studying how the birds use vocalizations in this decision-making process.”

Nest boxes, automated audio recordings and wildlife cameras

To this end, the behavioural ecologists are studying six populations of zebra finches in the wild. They have installed nesting boxes and wildlife cameras near water and equipped the nesting areas in dried river beds with sound recording equipment. “We already knew that male zebra finches sing to attract the females. But the males keep on singing even after the females have made their choices. We think that singing plays a role in their communication about breeding, but that it also has other social functions. We are analysing many hours of sound recordings to discover whether groups of zebra finches sing more around breeding time and how their activity is effected as the climate changes over the year.”

The researchers are also playing recordings of male zebra finch songs next the birds’ nests. They want to know why male zebra finches also inspect other nests and if they might be attracted by the song. “We are interested in finding out whether the males inspect other nests in order to make their own breeding decisions,” says Naguib. “Is this how they keep an eye on what their peers are up to? Inspecting other nests and synchronous breeding may also have another benefit: it allows the birds to expand the social environment of their offspring. This has advantages for choosing a partner, feeding and safety.”

Tracking

In the near future, the behavioural ecologists hope to equip the zebra finches with state-of-the-art miniature transmitters on their backs, as they previously did with different technology in great tits and nightingales. “We want to do a pilot project with tracking. The birds will be fitted with a recently developed solar-powered mini-transmitter which will allow us to monitor exactly how they move about the landscape throughout the year, both during and outside the breeding season. This will tell us how stable the social groups are, for example, and if groups of birds stay together throughout the year, and how they respond spatially to changes in their environment and weather conditions such as drought.”

“Our colleagues working in the lab are very excited about this major research being carried out in the wild,” says Naguib. “We are collecting a lot of additional information and we will learn much more about breeding decisions and how zebra finches cope with difficult conditions. It is important to understand how animals in general cope with extremely unpredictable changes in their environment, because this will help us to predict how climate change will effect animal behaviour and we can take this into account in environmental conservation plans.”

Males in good condition sing louder

Most zebra finches live in groups, but they often split up for a while so that pairs also spend a lot of time alone. The behavioural ecologists discovered that these birds sing a lot at the places where they gather. “We expect that one can tell which male is in good condition because he is likely to sing more clearly and loudly,” says Naguib. “We want to find out whether other birds follow these stronger males to look for food.” The research is funded by NWO, a major Dutch science funding agency, and the researchers are based at Fowlers Gap Arid Zone Research Station in western New South Wales