HUMANS are not the only ones likely to treat themselves to ‘duvet days’ on days when it is cold and rainy.
New research by Mark Walker and Professor Ian Rotherham of Sheffield Hallam University has found common swifts also enter a form of hibernation when the weather turns bad.
On cold wet summer days, the flying insects on which the swifts feed become scarce. Researchers found that on such days newly-hatched swifts were often extremely cold. But swift chicks appear to actively lower their body temperatures when the weather is bad in order to save energy, thus ensuring their survival.
Mark said: “This could be especially important for swifts which are totally dependant upon an unreliable source of food. They sometimes fall into a deep sleep on rainy cold days.”