This was fantastic! I shall never use the phrase "bird-brained" again, though - or at least not unless I am being complimentary. I knew that some birds were very clever, such as New Zealand's kea, which is at present being taught to use touchscreens down at Willowbank Wildlife Reserve in Christchurch, but the variety of cleverness that Ackerman describes is phenomenal. It ranges from navigation to artistic ability to abstract thinking and the understanding of probability, and really makes me rethink the way in which we think about intelligence. The idea that adaptation to environment affects brain function - even brain size - is not perhaps a new one, but it's applied here to birds - creatures that I find really appealing - and the way it's been presented is so effective, and so enormously readable, that I enjoyed every minute of it.