Frogs and toads usually go back to the pool where they have spawned. Natural selection means that this is a pond where they could grow to adulthood and therefore their tadpoles will to. Triggered by higher spring temperatures, they get together en masse, sometimes travelling a mile or more. Frogs make a sort of brrrp noise, half way between a burp and a purr. Toads make a higher pitched cry. It’s a noisy orgy in the pond at night and early morning.
The male climbs on the fatter female and does the amphibian clasp.The female lays the eggs, and the male emits the milt which fertilises them. The spawn is usually laid among surface weed, which forms some protection against fish and larvae. The transparent jelly round the newly laid spawn expands in the water by about 50%. The embryo inside feeds on it before hatching. Within a clump of spawn, some embryos hatch earlier than others – possibly those at the top of the clump where it is warmer. If the embryo dies, it turns white.