Red Admirals in Winter
2006 has been the warmest year ever, with the longest extended summer on record. It has also been a remarkable year for the Red Admiral, a butterfly which, until 10 years ago, was reckoned to be dependant on migration to survive the British winter. In mild climates, it hibernates as an adult, just like the Small Tortoiseshell, Peacock and Comma, so we would expect it to survive in Suffolk until the sharp frosts set in, but in a state of torpor. This November it showed its resilience, and flew on in good numbers right into December, outlasting its relatives as they sought shelter for hibernation.
It is well known for late appearances on bright sunny days, even at low temperatures. In 2002, one put in an appearance at Ixworth on Christmas Day, and that stood as Suffolk's latest record until this year, when they were noted in Ipswich on 30th December, and finally by Nick Dickson at Gislingham on New Year's Eve!
New Year's Day was bright and mild, at about 9 Deg C and the opportunity to bask in full sun brought at least 2 out, at Brent Eleigh and Ufford. These sightings were not latest-ever records, as New Year's Day 2000 had also brought sightings. Butterfly physiology demands that muscles must be brought up to 31 degrees for flight, and a rule of thumb suggests that this can be achieved from 15 degrees ambient by absorbing the sun's rays directly. The Red Admiral's predominently black colouration gives it the increased efficiency that allows it to warm up from a lower temperature. If January and February go by without severe frosts, we can expect 2007 to be another outstanding year for Red Admirals.
