Migrants on the move yesterday

Yesterdays migrants reported in Calderdale included 6 Spotted Flycatchers, 2 Redstarts, 2 Whitethroats, 1 Sedge Warbler, 30+ Willow Warblers, 1 Tree Pipit and a Whinchat. There were 6 Swifts at Elland GP but surpisingly no Swallow roost ? have they moved to another site ? last year on 18th August there were an estimated 5000 roosting.