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Text and photographs protected by Copyright © Adrian Hoskins 2007, and must not be published in part or in whole elsewhere without prior written permission from the author.
Butterflies of Britain & Europe
 
Red Admiral
Vanessa atalanta LINNAEUS, 1758
Family - NYMPHALIDAE
subfamily - NYMPHALINAE
Tribe - NYMPHALINI
 
 introduction | habitats | lifecycle | adult behaviour
 
Red Admiral Vanessa atalanta, female, Stansted Forest, West Sussex, England
 
Introduction
 
The Red Admiral is probably Britain's most well known butterfly, and certainly one of the most beautiful, with it's almost perfect pattern of red bands and white spots on a black background. It was first named as "the Admirable" by Moses Harris in 1766.
 
Click here to see the historic names of other British butterflies.
 
Red Admiral Vanessa atalanta, Noar Hill, Hampshire, England
 
The butterfly is widely distributed and common throughout mainland Europe and north Africa. In northern Scandinavia and in Britain it occurs as a migrant.
 
It cannot be confused with any other European butterfly except the similar Indian Red Admiral V. indica, which has a much wider, irregularly shaped red band on the forewings. It occurs together with atalanta on Madeira and the Canary Islands, and throughout much of the Oriental region, but is inexplicably absent from Europe and north Africa.
 
Elsewhere in the world there are several other Red Admiral species, including V. buana from Sulawesi, V. samani from Sumatra, V. dejeani from Bali, and the very beautiful
V. gonerilla from New Zealand.
 
Habitats
 
This species occurs in Britain as a migrant originating from northern Africa and southern Europe, and being an extremely mobile species, it can turn up in any habitat including woodlands, grasslands, meadows, heathlands and moors, coastal habitats, riverbanks, low montane habitats, gardens, parks, allotments and town centres. Males also gather at certain grassland hilltop sites, apparently to intercept migrating females.
 
The number of migrants varies according to climatic conditions in Europe, and in turn this greatly affects the number of UK bred butterflies seen later in the year.
 
Migrants arriving in the early spring oviposit on stinging nettles growing alongside hedgerows or in woodland glades, producing a summer brood in the UK which typically emerges from mid July to early August. In early autumn these butterflies migrate south, arriving in southern woodlands where they congregate to nectar at ivy blossom.
 
Red Admiral Vanessa atalanta, nectaring at ivy blossom, Stansted Forest.
 
There is now mounting evidence that in mild winters a small percentage of Red Admirals are able to successfully over-winter in southern England. They awake on warm days, and sightings are frequent in southern woodlands on sunny days between October and late January.
 
In normal winters they are usually killed by the hard February frosts, but in the very mild winter of 2006/2007 there were almost unbroken sightings in West Sussex, Hampshire and Dorset from October until the following March. The surviving adults laid eggs as early as January, producing a new generation of adults which emerged in early May.
 

Red Admiral sightings in Stansted Forest, winter 2006-2007

 

Sept

Oct

Nov

Dec

Jan

Feb

Mar

Apr

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Chart illustrating the build up of Red Admirals, as a result of southward migrations into Stansted Forest, 4 miles from the English south coast on the Hampshire / West Sussex border; and the rapid reduction in the population following the gales, frosts and snow of late January and early  February. After the first week of March, most of the surviving butterflies dispersed into the surrounding countryside. The progeny of the over-wintered butterflies emerged in early May, coinciding with the arrival of a new wave of immigrants.
 
On 9th November 2007, I counted a minimum of 12 Red Admirals in a small section of Stansted Forest, but estimated that at least 150 must have been present in the whole wood. Unfortunately, extremely wet and windy conditions prevailed over the following few weeks, decimating the population. On 23rd December however, I watched 2 Red Admirals basking on tree-trunks in the forest, despite having endured 6 consecutive nights of severe ( minus 3°C ) frost the previous week. At the end of January, in mild sunny conditions at least 3 Red Admirals were flying in the forest, but cold and wet conditions persisted throughout the spring, killing off the last survivors, and none were seen at Stansted after 9th February.
 
One of the hibernation sites at Stansted Forest, where large numbers of Red Admirals arrive each autumn. In exceptionally warm winters as many as 15 percent survive the winter, and disperse into the open countryside in early spring.
 

Red Admiral sightings in Stansted Forest, winter 2007-2008

 

Sept

Oct

Nov

Dec

Jan

Feb

Mar

Apr

40

          

35

          

30

          

25

          

20

          

15

          

10

          

5

    

1

    

Compared to the previous winter, 2007-2008 was cooler, windier and considerably wetter, with fewer sunny days. Frosts were minimal prior to March, which produced many icy nights. April began very cold, with snow, sleet and hail. The harsh winter conditions had no negative impact on other hibernating butterflies, with Peacock, Comma, Brimstone and Small Tortoiseshell all being recorded in average numbers in mid-late April.

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 very 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.
 
Red Admiral Vanessa atalanta, basking on hazel leaf, November 2007
 
Lifecycle
 

In late April and 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.

 

2nd brood adults, which may be of either UK or European origin, are less particular about oviposition sites. They will lay their eggs in any sheltered sunny lowland habitat where the foodplant grows e.g. in July 2008 in my Hampshire garden I watched 2 Red Admirals laying eggs on the same small clump of unkempt nettles. 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 and feeds 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 these tents are opened, the spiky greenish-brown larva can be seen within, normally curled in a J shape, head-downwards.

The caterpillars of most butterfly species tend to wander some distance away from their foodplants to pupate, but the Red Admiral is unusual, in that it forms it's greyish chrysalis within the caterpillar's leaf-tent.

Adult behaviour

 

Red Admiral Vanessa atalanta, basking on sweet chestnut trunk

 

Red Admiral Vanessa atalanta, basking on larch trunk

 

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.

 

Red Admirals are inquisitive, and will often investigate humans entering their territory. On several occasions I have been dive-bombed by individuals that have swooped to make contact with the top of my head. 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.

 

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
 
                                                       
Almost every British and European species of butterfly is declining rapidly in numbers, due in most cases to loss or degradation of habitats.
 
You can help to reverse the decline by supporting conservation organisations which purchase and manage habitats as nature reserves, and which lobby government at local, national and international levels, often very successfully, to bring about changes in farming, forestry and urban development policies.
 
Please contact the conservation organisations for advice on how you can help protect British and European butterflies and their habitats. You may be able to offer practical help e.g. by monitoring butterfly populations or helping to manage nature reserves. Donations to these organisations enable them to employ ecologists and biologists. Even if you are unable to provide such help, merely having your name on the membership list can be a powerful tool for conservation organisations wishing to demonstrate the levels of support they have for their policies.

 

 
Text and photographs protected by Copyright © Adrian Hoskins 2007-2008, and must not be reproduced or published in part or in whole elsewhere in any form without written permission from Adrian Hoskins. Breach of copyright will be pursued by litigation.
 
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