Chiffchaffs! Why?
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The three great mysteries of science: what is dark matter? how did life begin? what's behind the green door? To this can be added a fourth: why do Chiffchaffs chase other birds? It's something I see very frequently at this time of year. Typically a Chiffchaff will watch a Blue tit and wait for it to take off. The Chiffchaff then chases the tit around the garden, exhibiting a piece of behaviour known as 'giving it merry hell'. Why do they do it? They seem to expend a huge amount of energy on this, seemingly, frivolous pursuit. I've puzzled over this for, literally, decades. Back in the 90`s I wrote to Jim Flegg at the BTO about this - he replied 'That`s easy - it`s defending a feeding territory'. To me that just doesn't ring true. For a start they aren't fussy about their targets - I've seen Chiffchaffs chase a whole range of species including a Great-spotted Woopecker on one occasion. It's like the feisty small boy at