Small Tortoiseshell (Aglais urticae)
Chiddingfold Forest, 2016
The beautiful Small Tortoiseshell A. urticae can turn up almost anywhere and appears in gardens throughout the British Isles. It is one of our most successful butterflies. As its scientific name correctly suggests, it is most-often seen where nettles grow in abundance; both Common Nettle (Urtica dioica) and Small Nettle (U. urens) are used for egg-laying and larval nutrition. A. urticae is also frequently encountered whilst hibernating in an outbuilding, such as a garage, shed or barn, where they may be found in the company of other individuals. Further hibernation sites include hollow trees and woodpiles. I personally experienced some fifteen individuals overwintering in an old converted tractor shed last year. They were surprisingly first seen to be entering hibernation on 31st July 2015. They stayed in this state for eight months and only occasionally showed signs of any movement.
The adult butterflies can be seen on the wing at any time of the year, even on the last days of December or first days of January if the temperature is high enough to wake them from their dormancy. However, adults normally emerge from hibernation at the end of March and start of April. There are typically two broods each year, except in the north, where there is usually only a single brood. Whether single or double-brooded, the butterfly can be a familiar sight in late summer as it imbibes nectar to build up essential fats in preparation for its period of rest.
The above images show two separate males, the first, exhibiting dorsal thermoregulation on a forestry track in early July, the second, having successfully overwintered in the adult form, resting on a log pile in early April; the antennae tucked tightly between its forewings and showing the exquisite camouflage of the underside.