Very surprised and delighted to see waves of Pied Wagtails flying to roost in some tress and hedges at Southampton Airport this afternoon - I'd never seen or heard a mass roost before - other than the distant one on the M6 Forton services. I estimate there were over 150 birds joining the roost in the short time I watched - no idea how many there would be altogether! If anyone's passing through they were just in front of the hire car offices.