Kiwi resorting to desperate measures

A kiwi named Nick doing his best to keep cool. Picture / Backyard Kiwi

Kiwi in Northland are continuing to take desperate measures as they struggle to deal with hot, dry conditions. They have been seen sitting in streams to cool off and foraging for food in daylight, and while some rain and cooler temperatures over recent days will have given some respite, Kiwi Coast Far North co-ordinator Lesley Baigent does not expect that relief to last.

The birds were continuing to resort to a variety of survival tactics.

"Firstly, they're seeking shade and cooler nesting sites. They're nesting in cool, damp areas like drains or culvert pipes, in deep rock crevices in the bush and waterways and hollows in the banks of creeks and streams," she said.

Adult males sitting on nests were doing it hard, especially if they were exposed to the sun or far from reliable water. Some had been found with their egg close to the nest entrance, possibly to stop it overheating.

"Birds have no sweat glands, so they can't sweat to cool off like we do. Instead they pant, a little like a dog but more efficiently, with less water loss," Lesley said.

"They breathe much faster and use the air to suck moisture from the lungs and mouth. This then evaporates, using heat from the bird, which is lost in the breath. Feather-fluffing exposes more skin to the air, which allows more heat to be lost. Most birds can unfold their wings to expose more skin, but, alas, not the kiwi."

She had had reports of kiwi in and around creeks, dams and water troughs, and egg-carrying females had even been seen sitting in streams.

"Whether this is to cool the body or take the weight off their legs is unknown. It's hard work carrying the world's largest egg per body size in this heat," she said.

Meanwhile transmitter data showed kiwis' foraging hours had increased as food became harder to find. They were now active about 10 hours a night, and venturing out in daylight hours in search of food and moisture. The high activity of transmitter-carrying kiwi also indicated that some weren't attempting a second nest this season, or had abandoned it.

Despite those survival tactics, not all kiwi were coping. Scientists had found some adult males and juvenile females were underweight and in poor condition, and there was a marked difference between chicks hatched earlier in the season, which averaged 900g, and later arrivals, which were small and hence at higher risk of predation.