By mid or late February, something is stirring in the garden pond. On mild days you may hear what sounds like a distant motorcycle scramble, but really it is a chorus of common frogs.
Common frogs awake from hibernation with one thing on their mind. In early spring the females are swollen with spawn, which the male frogs fertilise as it is laid. The deep, purring croaks are to intimidate other males and attract the attention of females.
Male frogs grow pads on their forelegs that help them to grasp the females in an embrace known as amplexus. This secures them in position for fertilising the spawn, though ardent males will often clasp each other, in which case they are deterred by protesting croaks.
When the spawn is laid it absorbs water rapidly and swells so that often a portion will be left above the waterline. Usually this will come to no harm, but spawn is sensitive to frost, which can kill the developing tadpoles, especially if freezing conditions last.
In cold weather, an open, sunlit pond will thaw more quickly. If you are concerned about spawn in prolonged cold spells you could transfer it to a bucket of water and store it away from frosts until the weather improves. Remember to return it to the same pond as soon as you can.
There’s more information on spawn and tadpoles in your pond at the Froglife website.
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