Sand Martins at Llansantfraed

This afternoon I was delighted to see swarms of Sand Martins at the Lime Kilns near Llansantfraed. I had some guests and we stood watching them chase around below our vantage point on the cliff top. Very difficult to judge how many, they were so active and fast, but a conservative guestimate would be between 60 and 70, which leads me to think they are a nesting colony.