The wildlife trust said there were a few ospreys in Sussex at the moment at both Arlington and Weir Wood reservoirs, and one at Thorney Island in ChichesterHarbour.
From Thursday, 15 March, until Sunday, 18 March, the lines from Portsmouth Harbour to Petersfield, Fareham and Chichester will be closed and that will be extended to Haslemere, Swanwick and Eastleigh on Sunday only.