The researchers suspect that dark coloured birds evolved this silver sheen as a way to show off, while maintaining the benefits of dark coloured feathers.

BBC: Earth News - Birds unveil 'silver wings'

In the video, Zuur glides across emerald-coloured waters and skids off boat ramps set specifically for the once-in-a-lifetime ride.

BBC: Rare wakeboarding footage in the wondrous Jeita Grotto

With skills practised over the course of almost four decades here, he manoeuvres his horse to round up a group of recalcitrant, russet-coloured calves, heading off their meanderings with an authoritative click of his tongue.

BBC: The road to Hollywood, California

Police said the men then got back in their cars - a silver Peugeot 306, a black Volkswagen Passat and a dark coloured Vauxhall Astra - and drove off along Briscoe Lane towards Ten Acres Lane.

BBC: Arrests over attack in Manchester's Newton Heath

The men then got back in their cars - a silver Peugeot 306, a black Volkswagen Passat and a dark coloured Vauxhall Astra - and drove off along Briscoe Lane towards Ten Acres Lane, officers said.

BBC: CCTV shows 12 men attacking youths in Manchester