Having scored a good bonus at work, I am being responsible with most of it but did decide to treat myself to a new toy: a Sigma 150-500mm zoom lens. I have never really tried a seriously long lens before (traditionally, I am more of a look-for-tiny-stuff type), and the Sigma lens has good reviews and a reasonable price so I can try it out without taking out a new mortgage. Still some practice needed (I believe it is traditional to shoot the front of the bird, for example), but not bad for a first try.