Vlog: Flies and Helicopters

How do you tell a fly from a bee? 

And how many types of tree can you name that produce 'helicopters'? 

We're off on another rambling walk on the Chiltern Hills today to find out the answers to those questions. 

And there's a shout out to one of my best mates, Dr Erica McAlister too. She's a senior curator at the Natural History Museum in London and she specialises in flies. Amazing woman. 

Listen to her BBC Radio 4 series 'Metamorphosis' on BBC iPlayer. Go on! Go! (Click here)