White Stork at Sawley, Lancashire

April 3, 2010:
After passing over Padiham at mid-day yesterday (Good Friday) and being seen shortly afterwards at Ribchester, by late afternoon the bird had moved 15 km or so up the Ribble valley to a field next to Sawley Abbey. There it stayed overnight and for a short while this morning. On arrival shortly after 10.30am it had just taken to the air, soaring slowly and effortlessly in circles over the abbey and gradually gaining height all the time. Then, after about five minutes, it flew off purposefully up-river in a north-easterly direction and was lost to sight. Metal-ringed, it was possibly once in captivity. It is thought it could be the same bird as that seen near Burnley two years ago. If so, why return again to northern England, and at what might be considered its migration season?