Grey Wagtails have a clear preference for fast running water. As Bedfordshire is a relatively flat county there aren't many places that meet their requirements. In the north of the county, the only two breeding sites I know of are at water mills. A pair has bred at Bromham Mill this year. On Friday we ringed the second brood of two pulli.
An interesting find were pieces of Signal Crayfish in the river - a likely sign of a recent visit by an Otter.
Thank you to Roger and Adrian for your help.