Western Morning News (Saturday)
AMOROUS AMPHIBIANS
The South West tends to have the UK’s first frogspawn records of the year – even as early as January – so now’s the time to keep an eye out for evidence frogs have hopped into action and begun breeding, reports Charlie Elder
Daffodils and snowdrops have begun emerging from the cold earth, buds are appearing on frosty branches, birds have started practising their songs and the days are getting longer.
Even if normal life has largely ground to a halt during the current lockdown, our planet is still, mercifully, spinning on its axis. And while spring still seems a way off, there is a sense in the air that nature is eager to shrug off winter and impatient for the seasons ahead.
It may be early in the year, but there is one thing worth keeping an eye out over the weeks ahead, particularly in milder weather: frogspawn.
Nothing says spring like frogspawn, but in favourable conditions froggies can go a-wooing in the South West as early as mid-January – and there are already records of frogspawn in Cornwall this year.
It is always a sight to raise a smile on a cold day: gelatinous mounds of spawn eyeballing you from the margins of ditches, ponds and waterlooged hollows, as if it had rained full stops.
And it is one that conjures up memories of childhood days collecting clumps of spawn in jam jars and bowls and nurturing tadpoles on a window sill indoors. It is a perfect way to get children interested in nature, though, judging from past experience, successfully seeing spawn through to the froglet stage over two to three months is not as easy as one thinks.
Our common frogs tend to breed earlier than toads, laying spawn containing thousands of eggs in tapioca pudding dollops, while toads wrap strings of eggs around vegetation.
Breeding frogs can be heard croaking, particularly at night, as they congregate in shallow water. It is a soft guttural purring sound – nothing like ‘ribbit’ – and always comes as a pleasant surprise when you chance across a group calling away in a pond, heads breaking the surface with that comical expression of theirs.
Gatherings, which peak from late February to March, are vulnerable to predation – frogs being on the menu of everything from herons and hedgehogs to stoats, rats, foxes, otters and owls.
Unlike toads they are not faithful to their birthplace and are opportunistic when it comes to breeding sites. The scientific name for the common frog is Rana temporaria for a reason – they don’t stick around after breeding. They can also lay their spawn in temporary pools – gambling that they don’t dry out before their offspring leave the water.
The froglets that develop from tadpoles generally emerge from a pond between July and September, and take two to three years to reach breeding age.
Adults spend much of the year feeding away from water, catching insects, slugs, snails and worms with their long sticky tongue, and spend the winter hidden in a crevice or even submerged at the muddy bottom of a pond.
The frog has always been a likeable and eccentric part of our wildlife: big-eyed, full of bounce and the inspiration for such characters as Beatrix Potter’s Jeremy Fisher and the Muppet Kermit.
While a familiar species, it may be confused with the toad as they share many similarities. The common frog is long-legged and smooth skinned, unlike the ‘warty’ toad, and has a slight ridge on either side of the back, dark bands across the legs and a dark patch behind each eye. They are olive-brown or greenish-grey in colour, however colour and markings vary, with some yellow or reddish in hue and individuals may be light or dark.
Annual surveys are carried out by the amphibian and reptile conservation charity Froglife, the Freshwater Habitats Trust and local Amphibian and Reptile Groups to record when and where frogspawn is laid – and the South West generally leads the way with the first breeding records of the year. Milder weather can advance the laying season by days – though really early spawn at the surface runs the risk of being killed if the temperature falls and the water freezes.
The surveys show that ponds without fish tend to have healthier amphibian populations, as fish – among other creatures – may eat tadpoles. Medium-sized and larger ponds typically get more spawn than those under a metre square and natural fluctuations mean there can be good and bad years for ponds, which may play host to a congested bubbling bath of mating frogs one spring and hardly any the next.
It is thought that around one in fifty eggs actually makes it out of the water as a fully-formed froglet, so dense rafts of spawn in a pond doesn’t mean that a garden will be overrun with hoppity frogs come the summer.
If spawn is being eaten by birds and fish then Froglife advises it can be removed and raised in an aquarium or container, being eventually returned to the same pond to avoid unwittingly spreading disease.
Frogspawn needs light to develop, especially as newly-hatched tadpoles feed on algae growing on pond plants and rocks exposed to the sun. They begin life as herbivores but later become omnivorous, feeding on decaying matter and tiny creatures.
The miracle of metamorphosis is engaging to observe over time as spawn gradually changes from dots to commas to tadpoles, with rear legs developing and the tail shrinking as they become tiny froglets.
If you do attempt to raise spawn the advice is not to take too much and to return offspring to the same pond. Tadpoles should be kept in water taken from a pond or rainwater, rather than tapwater – unless it is left to stand for a few days.
They need pond weed to feed on and boiled and cooled lettuce or spinach provides a good alternative.
As the tadpoles grow bigger, fish flakes for cold water fish provide an excellent source of nutrition,
and to avoid the water becoming polluted it needs to be regularly refreshed or replaced.
Finally, as they develop into froglets they need to climb out or they will drown, so require shallow water, moss and rocks. At this stage release them in damp grass beside the pond – it’s time for them to hop it.