Flemish nature preservancy organisation Natuurpunt today officially launched its annual butterfly census, with one difference – this year, the count will take place until the end of the month instead of lasting only one weekend.
The census has taken place now for 12 years, with volunteers asked to count the number of butterflies visiting their gardens and other properties such as orchards and farms. This year the counting will be more intensive than usual, in order to give a clear picture of the effect on butterfly populations of the extreme weather of last summer.
“We always have the hope that the count will coincide with the peak in butterfly numbers, at a time when there are a lot of them about,” Wim Veraghtert of Natuurpunt told VRT News. “But in recent years we’ve missed the target. Last year we brought the weekend forward to end July, but even that was too late, because the peak had fallen at the start of the month.”
Natuurpunt blames climate change on the fact that the weather in recent years has become more and more difficult to predict. “In fact there are no normal years any more,” Veraghtert said. “Last year was very warm and dry. In 2013 there was a cold spring. So it’s not easy to say when the butterfly peak will arrive.”
For the last two years, the small cabbage white (Pieris rapae, pictured) has been the most common butterfly in the gardens of Flanders. Five other species give cause for concern, the organisation said: the small tortoiseshell, map butterfly, red admiral, anglewing or comma butterfly and the peacock butterfly. For these species, the spring numbers were disappointing, and the summer generation is expected to be reduced in numbers.
“These butterflies are all dependent on stinging nettles to lay their eggs on, and the caterpillars eat the nettles. But during the warm, dry summer of last year, a lot of nettles withered and dried out. But we are expecting to see more of other species, like the swallowtail, which like the warmth.”
To take part, in Flanders and Brussels, go into the garden for 15 minutes at a time. Count the number of butterflies you see and identify them, using the form on the Natuurpunt website. Results can be submitted until 28 July.