Summer’s washout failed to dampen the prospects for the red admiral, one of the UK’s most popular butterflies, whose numbers rose by 75% compared with last year, according to the annual Big Butterfly Count.

Other butterfly species were less fortunate, however, with declines seen across the three common species of white butterflies. The green-veined white and both the large white and small white were down more than a third on last year, reflecting difficult weather conditions.

The red admiral is one of the best recognised butterflies in Britain thanks to its distinctive black, orange and white markings. More than 73,000 were counted in this year’s census carried out by the Butterfly Conservation charity between 14 July and 6 August. The large showing came on the back of a bumper year last year, and a mild winter and spring that helped some of the species stay in the UK – a new development in recent years, possibly assisted by a warming climate, for what used to be a summer visitor from southern Europe.

The red admiral was not the most numerous butterfly in the count. The gatekeeper, also known as the hedge brown, with orange and brown wings and prominent black spots, was seen more than 93,000 times, up nearly a quarter on last year.

This year’s wet summer, the 11th wettest on record (though temperatures were above average), spelled poor conditions for butterflies, which thrive in warmer and sunnier summers. Last year was also a bad year for butterflies and moths, so improvements this year are relative in many cases.

The gatekeeper butterfly, also known as the hedge brown, was seen more than 93,000 times, up nearly a quarter on last year. Photograph: Mark Searle/Butterfly Conservation

It was a bumper year for the count itself as a record 60,000 people took part in the three-week census which is the world’s biggest survey of butterfly numbers. More than 550,000 butterflies were recorded, but the record number of surveyors hides a more concerning picture: each participant saw on average only about 11 butterflies, the lowest number per person since the count began in 2010.

Richard Fox, head of recording at Butterfly Conservation, said: “It hasn’t been a vintage summer for butterflies, but there have been some real positives. The highlight has been the huge number of people that have got involved, spent time enjoying and counting our native butterflies and moths, and done something useful and important in the face of so much wildlife decline.”

The other most numerous butterflies spotted by volunteers were the meadow brown, whose numbers were third highest, the peacock with nearly 30,000 examples, the common blue with nearly 20,000, and the speckled wood butterfly at more than 18,500.

Despite the good news for the red admiral, butterflies in the UK are under threat, both from a changing climate, with the last 10 years showing a pattern of damper summers, and from human factors. Butterflies are losing their habitat as a result of intensive farming, pesticides, urbanisation and populations becoming cut off, and the added pressure of weather changes is having an impact on their breeding and food sources.

Butterflies and moths are also valuable to farmers and gardeners as pollinators, though on a smaller scale than bees.