About half a million people are expected to take part in the RSPB's annual Big Garden Birdwatch this weekend - which helps the charity keep track of species numbers.
Inspired, Evan Davis took a trip to Brent Reservoir in the shadow of Wembley Stadium in north London, to meet a father and son pair of birders.
Comedian Alex Horne and his dad Hugh, or "Duncton" as he prefers to call him, spent a year seeing who could spot the most different species of bird.
Here is what happened when birdwatching novice, Evan, caught up with them.
Click 'show captions' for photo information. Not all images have captions.
Photos by Paul Kerley, and courtesy Brian Gadsby/Leslie J Borg/John Devries/Science Photo Library.
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