Having ponds for rainwater harvesting, lots of frogs and toads are attracted to the garden. This is good because frogs are a sign of good ecology and they keep pesty insects under control. Here is a video of frogs spawning, one female and two males! The white foam is a nest in which the eggs are deposited. The foam nest protects the eggs from microbes and predators, to some extent – I have seen the turtle in the duck pond eating the frog eggs!