He says to understand what the birds are doing and whether this sets them apart in any way, the same experiments need to be carried out, multiple times, on many different species, to properly compare results.

BBC: Meet the brains of the animal world

In both cases, the experiments would be tiny compared with what people are already doing.

ECONOMIST: Geoengineering

The researchers at Cern in Switzerland and Gran Sasso in Italy have tried really hard to find what they might be doing wrong - over three years and thousands of experiments - because they can hardly believe what they are seeing.

BBC: Light speed: Flying into fantasy