The low number of Red Admirals arriving in autumn 2007 was mainly attributable to lower breeding success and reduced immigration during the exceptionally cool and wet summer. The maximum count was on 21st October when 17 were recorded nectaring at ivy flowers. Winter survival rates were very low, with only one sighting in March, and no more until 2 immaculate and extremely active individuals were seen on 25th May. Their condition and behaviour strongly suggested  they had emerged locally within the previous couple of days - providing fairly conclusive evidence that they were the progeny of post-hibernation adults that had successfully over-wintered at Stansted Forest.

In late April and early May, female Red Admirals can be observed flying around nettle patches in woodland glades. They periodically alight on nettle leaves Urtica dioica, upon which they lay a single egg. Usually a dozen or so eggs will be laid on any sizeable nettle patch. Egg-laying is interspersed with periods of basking and nectaring - typically at blackthorn, crab apple, and wild cherry.

Second brood adults, which may be of either UK or European origin, are less fussy about oviposition sites. They will lay their eggs in any sheltered sunny lowland habitat where the foodplant grows e.g. in July 2008 I watched 2 Red Admirals laying eggs on the same small clump of unkempt nettles in my garden. Each laid about a dozen eggs between about 11.00am and 1.00pm. The eggs were all laid singly on the upperside of terminal nettle leaves. The egg-laying bouts, which each lasted about 2-3 minutes were interspersed with periods of basking, and periodic flights to nectar at a Buddleia bush a few metres away. Interestingly a Comma was ovipositing simultaneously on the same nettle patch, and neither species seemed disturbed by the presence of the other.

The larva lives within a tent of folded nettle leaves, spun together with silk. Every few days, as the leaf-tent gets devoured, the larva moves house, and spins a new tent nearby. If the tent is opened, the spiky greenish-brown larva can be seen within, normally curled in a J shape, head-downwards.

Red Admiral Vanessa atalanta, basking on larch trunk © Adrian Hoskins

On sunny days the butterflies often bask on tree-trunks, always assuming a head-downwards or sideways facing position. In warm but overcast weather they like to bask on the foliage of bramble, hazel and other bushes.

In early spring Red Admirals nectar at sallow catkins and the blossom of blackthorn and hawthorn. Favoured summer nectar sources include dogwood, hemp agrimony, bramble, marjoram, devil's bit scabious, ragwort, burdock, spear thistle and ivy blossom. They also visit dung, or imbibe mineral salts from damp ground, and attend sap runs on oak trunks. In gardens they will nectar at Buddleia, ice-plant and michaelmas daisies. In orchards they will feed at fallen apples or pears.

Males are highly territorial, chasing after Commas and Peacocks as well as other Red Admirals. When nectaring however they will accept the presence of other species, and I have often seen mixed groups of Red Admirals, Silver-washed Fritillaries, Commas, and Large Whites gathered on a single flower head of hemp agrimony or Buddleia.

Vanessa atalanta, nectaring at hemp agrimony, Arnside Knott, Cumbria © Adrian Hoskins 

At night, on cold overcast days, and during the winter months, Red Admirals roost head-downwards on the trunks or lower branches of oaks, larches and other trees, where the bark-like underside of the wings provides them with excellent camouflage.

Red Admiral Vanessa atalanta, roosting on larch trunk © Adrian Hoskins