The sand martin's twittering song is continuous when the birds are on the wing, and becomes a conversational undertone after they have settled in the roost.
The typical number of individuals, around 200, is relatively low compared to other bird species (1,400 individual beetles for house sparrow, 2,000 for sand martin).
The birds which are known to nest or visit include blackcap, common chaffinch, grasshopper warbler, grey partridge, kingfisher, sand martin, skylark and sparrowhawk.
