The recent cold weather spell following a mild winter could spell bad news for UK wildlife this spring, conservationists have warned.

Frogs, butterflies, birds and bees could all struggle after a mild start to the year was followed by an extended cold snap, with the coldest April night in 70 years and snowstorms across the country, the Woodland Trust said.

The charity’s Nature’s Calendar citizen science scheme, which gathers sightings of the signs of the seasons from the public, shows many insects were active before the cold snap.

Brimstone, red admiral and peacock butterflies, along with ladybirds and red-tailed bumblebees, had all been recorded in Nature’s Calendar after emerging earlier due to a mild spring.

But they may struggle to survive if the wintery weather continues, and with fewer pollinators and extended snow, tree species such as willow and blackthorn which are now flowering may not thrive this year.

The cold conditions may also affect birds, which have already started nesting, and frogspawn, the Woodland Trust said.

Lorienne Whittle, citizen science officer for the charity’s Nature’s Calendar project, said: “We’ve had record-breaking early springs in recent years and 2022 was largely following a similar mild pattern, until the recent cold weather.

“Nature’s Calendar records have shown than many insects have awoken and we’ve all enjoyed these spring sights on the sunnier days through March.

“However, insects struggle in sub-zero temperatures, for example, bees will not fly in snow or very wet conditions.”

She added: “Last year, we had incredibly late frosts at the end of April, which caught out a lot of gardeners as well as having a negative impact on trees like oak and apple trees, which flower around then.

“We’ll be keeping a keen eye on the Nature’s Calendar records through the rest of spring to see how this season pans out.”

People up and down the country have submitted records of blackbirds nesting to the citizen science project, as well as some sightings of them feeding their young.

Blue tits, great tits and rooks have also been recorded building nests, with some already near to hatching their eggs, and the Woodland Trust warned cold conditions may mean birds have to work harder to incubate eggs and find food.

And while frogspawn can survive a short period of being frozen over, an extended cold snap could spell disaster for this year’s young.

Some frogs may have laid spawn very early this year as a result of the mild spring, with tadpoles now struggling in the cold, Ms Whittle added.

She said: “Our wildlife is facing a plethora of pressures in the UK and Nature’s Calendar records are critical in tracking one of the most significant – that from climate change.

“As our winters continue to become milder, springs earlier and we get more unseasonable weather, our plants and animals will have to adapt. We need the public’s help to track these changes.”

– To find out more about Nature’s Calendar and submit signs of the seasons, people can visit