The common frog (Rana temporaria) is a common garden species, especially for those with or near a pond. It has long stripey legs, large eyes and wet, smooth skin. It breeds in ‘spring’, which can be as early as December in Cornwall but as late as April in Scotland. However most spawn is laid in February and March.
Female frogs develop spawn in summer when food is abundant, and then overwinter with it. They emerge from winter torpor and head straight to their breeding ponds – if you have a pond you may see them arrive on rainy days, either on their own or ‘carrying’ a male. Males clasp on to females in the mating position known as ‘amplexus’ – those that find a mate on the way to the pond may get a head start on proceedings.
Spawn is laid in clumps in the warm shallows of the pond, often in a spot that gets the morning sun, which warms more quickly than other parts of the pond, and where any ice will be first to melt. Tadpoles hatch within a few days and usually take around 14 weeks to become froglets. However the rate of tadpole development depends on several factors, including temperature, availability of food and ‘overcrowding’, so it’s not unusual for there to still be tadpoles in your pond in autumn. Some may even overwinter in the pond as tadpoles, if they survive the low temperatures they will be first to become frogs the following spring.
How to help common frog
It’s thought the common frog is declining, thanks to changing weather patterns associated with climate change. Warmer winters, colder springs and drier summers appear to be impacting frogs’ behaviour patterns, with some not turning up for spring breeding and others spawning at the wrong time of year. On top of that, ponds that dry out in early summer could prevent tadpoles from completing their lifecycle.
The best thing we gardeners can do for frogs, therefore, is to dig a pond and keep it topped up in summer. Frogs seem to prefer shallower ponds, or larger ponds with plenty of shallows, where they can lay their spawn. A good frog pond should have shallow margins that get the morning sun in spring but are partially shaded in summer, so it doesn’t get too hot and dry out. Grow plenty of plants around the edge of the pond so froglets can hide from predators as they emerge from the water, and grow a good mix of floating, emergent and submerged plants in the pond so the tadpoles can hide from predators such as dragonfly larvae and water beetles. Beyond the pond, a large open compost heap, a log pile or ‘cairn’ made of stones will create the damp nooks and crannies that frogs need to shelter and find food. These terrestrial habitats are particularly important if you or your neighbours have cats – having plenty of hiding places dotted around the garden can make a huge difference to the fortunes of these precious amphibians.
Frogs eat invertebrates, including flying insects, small slugs and worms. Catering for frogs therefore means catering for invertebrates. Let areas of grass grow long for flies and other insects to take shelter, grow nectar-rich flowers for pollinators and mulch the soil to increase worm activity. It goes without saying that a frog-friendly gardener should never use pesticides. Embrace nature! And let frogs do your pest control for you.
