What kind of bee is this mostly black bee, inspecting holes in sleepers?

Bird of prey seen by tractor driver rolling newly sown oilseed rape. Described as kestrel sized with swift like wings so must be hobby. #tractorbirding

First decent influx of migrants on the potato ridges this year, 3 yellow wagtail and 3 wheatear #potatoplant25 #tractorbirding

Dotted Bee-fly on The Clive escarpment, Pattingham. #FarmedwithNature