Koel comment

["Philip Veerman" <>]

Martin's comment is quite fair and is an update with new numbers of the GBS Report comment, as to that most records are in recent years. That is a simple statistical corollary of that the species was rare in the early years of the GBS and is not now. So clearly the change has been something dramatic. Wilson's book notes the same thing.

 

Martin's graph is a good idea but it is not visually convincing on statistical grounds that there has been a widening of the number of weeks at which the species has been here recently. Though there is no reason why that wouldn't be the case. There are other ways to examine the same data that may show any trend more convincingly. As the species comes more often they may well arrive earlier and stay later. As for changes in observability, I doubt that. It could be that we have become more aware off them, but as they make themselves obvious, they should have been noted at the same rate years ago when they were rare.

 

Philip