male brimstone is jinking across the garden as I write this. Hearts have been given a much-needed lift across the nation this week as the first authentic spring weather of 2020 heralds the first butterflies. The butter-yellow brimstones patrol ivy and other evergreens where the paler green-yellow females have hidden all winter. One thing is on their mind: find a mate. The other four British species that hibernate as adult butterflies – commas, small tortoiseshells, peacocks and red admirals – are seeking the same in parks and gardens. Next to emerge will be chrysalis hibernators: speckled woods, holly blues, orange tips and the whites. I’m a bit anxious about this year because I have followed some hibernating caterpillars through winter and all but one have perished in the recent wet, mild and very windy conditions (caterpillars prefer cold winters). But I’m also hopeful about 2020. Last summer was the best butterfly year since 1997, the eighth best in 44 summers of scientific recording. It was good partly because 2018 was so hot. Butterflies steadily build up their population if there is a series of fine summers (the late 1940s were famously good). Could good butterfly summers come in threes?