Peter Martin writes:
Due to global warming and its ability to over-winter as a butterfly in this Country now, the Red Admiral may be seen flying during any month of the year. I have chosen this species as my butterfly of the month, as I have rather special memories of Red Admirals in September.
Barbara and I often holiday on the Isle of Wight at that time of year and, one September, we went to see a “Birds of Prey Display” at Appledurcombe House. After the show had ended, we walked around the House grounds and, to our surprise, came across dozens of Red Admirals nectaring on rotting damsons that had fallen from the trees. The damsons had started fermenting, which caused the Red Admirals to become rather “drunk” and this meant that we could walk among them and inspect them closely. In normal circumstances, they would have flown off before we had the chance to really appreciate their beauty.
The butterflies that survive our winter may be seen in small numbers from January onwards on warm, sunny days, but, throughout the spring and summer, home-bred specimens are added to by varying numbers of migrants from North Africa and the Continent. They travel even as far north as the remotest Scottish isles.
Red Admiral butterflies lay their eggs singly on the young leaves and shoots of Common Nettle leaves in sunny positions. There are two forms of caterpillar – some yellowish, some blackish – and, when they emerge after about a week, each makes a little tent by doubling up a leaf and fastening the ends with silk. Over the next four weeks, it feeds in a succession of leaf-tents. When it is full-size, it spins two of three nettle leaves together and pupates within this tent. The butterfly emerges after about three weeks.
The greatest number of Red Admirals seen in any month is probably during early September when they can nectar on Buddleia flowers. By pruning these plants in March, the Buddleias are usually at their best when there are fewer other flowers for the butterflies to gain nectar from. As well as damsons, Red Admirals like other rotting fruit, so, if you can put up with any wasps that might be attracted, leave a few rotting apples of plums for them.