Big movement of Swifts

A morning working at my computer proved productive. At least 200 Swifts passed the window, in groups of 5-10 birds, all heading south west. I've mentioned before about the frequent passage of birds over my house, always in a south west or north east direction, and this is yet more evidence. If you draw a line on an OS map from the centre of Carr Mill Dam to the centre of Prescot Reservoirs, not only does it go right over the centre of Eccleston Mere, it also goes right through my house, and if you extend it past Carr Mill Dam in the other direction, it goes right over Billinge Hill. Fieldfares, Redwings, terns, gulls, waders, Osprey, hirundines and Swifts, it's amzing how many birds seem to follow this line in one direction or the other. Some I suppose are just moving betweeen the dam, the mere and the reservoirs, but others perhaps are using it as a route to the coast.