Every year, a secret tribe take to the roads of Britain. In the space of a few months they will drive thousands of miles and spend thousands of pounds in pursuit of their prey. Their aim is to see as many birds as possible, wherever that bird may be.
Welcome to the very competitive world of the twitcher - obsessives who'll stop at nothing to get their bird.
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Ready to Watch BBC Documentaries, Season 2010, Episode 144?