What becomes very clear through the pages of this portrait of obsession is that while our feathered friends may be the objective of The Big Year competition, it's the curious activities and behavioural patterns of the pursuing "homo sapiens" that are the real cause for concern. It's a contest that reveals much of the human character in extremis - a tendency towards passion and deceit, fear and courage combined with that fundamental craving to see, conquer and categorize, no matter how low the stakes. As the author brings to life and gets under the skin of this extraordinary, eccentric triumvirate of obsessive "birders" he empathizes with and eventually succumbs to the all-consuming nature of their obsession.