Australian heat wave could lead to mass die-offs of birds

Budgerigars drop dead in the heat in Western Australia

"Heat waves in 2009 and 2010, which did not reach the intensity of the current record-breaking heat wave, led to large die-offs of birds in parts of Australia" says Prof. Andrew McKechnie. Over the last few days, people are beginning to report finding dead birds in their backyards on Twitter. Conditions are likely worsening as the heat wave wears on.

An international research team, led by researchers at the Percy FitzPatrick Instutute of African Ornithology at the University of Cape Town, are investigating how heat waves affect the physiology and behaviour of birds. They are on high alert for reports of impacts of the current Australian heat wave as such events will be valuable for predicting how climate change will affect birds.

Birds lose condition above 35 ºC
A recent study by the team in Southern Africa's Kalahari revealed that on days when temperatures exceeded 35 ºC, a temperature far below those currently being experienced across much of Australia, wild birds began to lose body condition. "At higher temperatures, the demands of keeping cool meant that the bird's ability to forage was compromised and their feeding rate declined as temperatures increased" says Dr. Rowan Martin of the Percy FitzPatrick Institute. These effects could accumulate over a number of days with long-term consequences for populations.

Another study by the team, in collaboration with the University of New Mexico, suggests that at higher temperatures impacts could be more immediate. At temperatures of 45 ºC, and without access to water, the time for hydration levels to drop below thresholds critical for survival could be as short as 4 hours for a 5g bird, or 5.5 hours for a 25 g bird.

Many Australians are putting out extra water for wild birds and other animals which could prove critical to their survival. Ensuring such water dishes are placed in the shade may help further.