From David Holland:

Last week (27.11.07) I encountered a huge pied wagtail roost in town. Coming to the end of a shopping foray I was walking up Parker Street from Church Street towards Clayton Square at about 5.30 and became aware of bird noises aloft. Looking up into the tops of the three trees in the centre of Parker Street I saw a vast number of pied wagtails swirling around. They were impossible to count but I arrived at a minimum count of 200+. Two days later I was back in town again (glutton for punishment!) and going up Parker Street, but just 15 - 30 minutes later. By that time they had all settled down to roost for the night and were somewhat easier to count. I was confident in reaching 300+. Several communications later with the guys who know about these things I learned from Steve White that this is a regular occurrence, although the location seems to move around a bit. A count of 267 was recorded in 2006 in Church Street by Paul Slater. A more precise count would be interesting this year.
Other stories:- Calderstones Park on Wednesday 28.11.07 produced two grey herons on the big island and . . . a cormorant fishing at less than 20 m from me. Has anyone ever seen a cormorant here before?