Richard Collins: Bird migration is dangerous and demanding — why do it? 

It was originally thought birds migrated to save energy in a warmer climate but new research is challenging this idea

Scientists fitted data-logging devices to 120 birds to measure their heart-rate and body-tempearture every half hour throughout winter.  Picture: iStock

‘The ouzel cock so black of hue With orange tawny bill...’ – Bottom in A Midsummer Night’s Dream

Some of us are stay-at-home birds, while others are restless souls not content to remain in one place for long. There’s a motor vehicle for every two people in Ireland and more than a million passengers are airborne, worldwide, at any given time. How odd!