Some years ago my father installed a deluxe pond in his back garden, which to the untrained eye may look like an old water tank. At this time of year it is full of mating frogs, probably 15 or 20 at any one time.
 They're difficult to photograph in their full writhing glory because they dive to the bottom if someone approaches but here are a few snaps. As I stood nearby with my camera there was a lot of croaking going on and the undergrowth was alive with frogs crawling and hopping to and from the pond.
 Any standing water in the garden is likely to attract them. On a smaller scale I dug a trug type bucket into the ground and every year frogs come to it, peering out from the murk.