Just witnessed some extraordinary Crow behaviour. I was sat in my garden and the usual 50 or 60 resident House Martins were hunting insects a little above treetop height. I then became aware of a Carrion Crow flying erratically and saw it was trying to "chase down" a House Martin "Falcon style", it obviously lacked the agility to particularly trouble the Martin - this went on for over a minute and as they were about to disappear a second Crow in pursuit of another Martin appeared, both Birds then disappeared from my view still in pursuit of their respective Martins. The Martins were making their normal flight calls, none alarmed in the way they would if a Sparrowhawk was flying by. About 2 minutes later presumably the same two Crows languidly returned and took up perches in their usual tree. I cannot believe this was a serious attempt by the Crows to catch a Martin, unless they were cognisant these were just fledged birds ? The only other explanation I can suggest is they were juvenile Crows just having a bit of "Fun" - anyone any ideas or seen this before ?