Things have got a little better. There were 4 frogs in the pond later in the day (Friday), including a mating pair. The following morning there was a nice clump of spawn in the pond and later still I counted about 24 frogs. However nearly all were males. On reflection I think nearly all of the dead have been females. I pulled another two dead frogs out of the pond, one with an amorous male attached to it still. The pond is very silty and so its difficult to see everything in it. On Sunday I pulled another ill-matched couple out. As its gone colder numbers have fallen. This morning there was some ice back on the pond, though at least one frog was present. They must be having a pretty tough time of it though.