Date: May 16, 2018
Source: Lund University
For decades, researchers have
thought that access to food determined the brood size of birds. Now, biologists
at Lund University in Sweden have discovered a completely new explanation: the
body temperature of small birds can increase by more than 4°C to exceed 45°C
when they are feeding their young. Larger broods would require more work,
resulting in even higher body temperatures -- something the birds would
probably not survive.
"A body temperature of over
45°C must be close to fatal even for small birds," says Jan-Åke Nilsson,
professor at Lund University.
Small birds, passerines, normally
have a body temperature of around 41°C. Jan-Åke Nilsson and his colleague Andreas
Nord studied marsh tits, discovering that their body temperature increased
considerably as they worked hard, for example when feeding their young.
Flying back and forth to the nest
means they do not get the opportunity to get rid of excess heat, resulting in a
higher body temperature.
