As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Sunday 7 July 2019

Aussie birds turn down their thermostat to save energy in winter

JUNE 27, 2019

Research published in Biology Letters by scientists at Western Sydney University provides the first clear evidence that a species of perching bird (the passerines) can employ torpor—an energy-saving mechanism whereby the body temperature of an animal is temporarily reduced in a controlled way during resting.
In this new research, the authors used miniature radio-transmitters to record the skin temperature of these tiny eight-gram birds over several weeks during winter in woodland near Sydney. Skin temperature provided a close approximation of body temperature in such small animals. Remarkably, they showed these fairy-wrens allow their body temperature to decrease substantially during their nightly roosting phase. These periods of nocturnal torpor closely resemble the torpor that is well-known in some small mammals and in a few non-passerine bird groups like hummingbirds. This new evidence of regular use of torpor by a passerine bird is important for understanding the physiology and ecology of birds.
Birds are typically small and light, which helps them to fly and escape from predators but means they cannot carry a lot of fat and this presents a challenge during winter when food is hard to find. The use of torpor provides a very effective mechanism to reduce the amount of energy required for thermoregulation when resting during the night. Torpor could be an important strategy allowing small birds to cope with limited and fluctuating food supplies.
"Even in a relatively mild climate, superb fairy wrens benefit from the energy-savings that nocturnal torpor provides," said Dr. Christopher Turbill from the Hawkesbury Institute for the Environment at Western Sydney University.

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