Red Admiral: This spectacular butterfly probably got its name from the ‘royal navy ensign colours’ of its wings rather than being a corruption of ‘admirable’ which it also undoubtedly is! It is a butterfly which traditionally did not survive British winters and so our butterflies came in several waves of immigration – first from North Africa and Southern Europe, then from Spain and Portugal and lastly from Eastern Europe. The offspring of the butterflies that came to the UK do, to some extent, head back south again. The variable numbers of this butterfly in the UK each year reflects the size of these several immigrations. With milder winters it may be that there will be some homegrown butterflies as they can be seen flying in any month of the year. Unlike Peacocks and Small Tortoiseshells, they do not go into proper winter torpor for hibernation. It maybe that caterpillars and pupae can also survive our winters in increasing numbers, which provide some of the early butterflies seen in March and April. The main food plant is stinging nettle and eggs are laid singly on the top surfaces of suitable nettle leaves. The caterpillar constructs a tent out of the leaf so remains hidden for its whole life. New tents are made as it grows and finally forms the pupa inside a tent made from a folded nettle leaf. Do try looking for them on nettles. There are no distinct generations with so many immigrants coming in widely variable numbers throughout the summer, but all the life stages can be found in most months of the year. In autumn they can be seen feeding up on the sugars in ivy flowers or rotting fruits before heading south. There is considerable interest in just how much they are now overwintering in the UK successfully, so records in December and January would be particularly interesting.
Photos John Ball Robert Maxwell Wood