The House Martin colony nesting on properties along Shearwood Crescent, Crayford, next to Perry Street Farm and Stoneham Park, has at least 9 nests this year, of which 3 were in definite use when I had a quick look when passing by on 13th July. Two are under roof overhangs on two-storey buildings and seven are on three-storey ones.
If you wish to experience House Martins flying around you at head height, then go and stand in the park late on a sunny afternoon.
The species is now amber-listed nationally due to a decline in numbers. The London Bird Report for 2014 records 200 actual or probable breeding efforts at 41 sites in the whole of London. More accurate data will emerge from the ongoing British Trust for Ornithology survey, but the species is thought to be in decline in the capital too.
Other known breeding sites in Bexley are in the Slade Green/Crayford Marshes area and at Chandlers Drive in Erith. We would be interested to hear about any others, and from anyone who lives or visits friends or relatives at the latter site, as it is some time since any counts were done here and previously there was evidence of destruction of nests by residents.