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Red Admiral
Behaviour and Ecology Because of its migrant status, the numbers of Red Admirals seen in Britain and Ireland can vary tremendously from one year to the next. With no specific habitat requirements and a widespread foodplant (common nettle), the Red Admiral is found right across Britain & Ireland. However, it is most common in southern parts, and it is in these southern counties that most of the overwintering individuals appear to be reported. The first wave of immigrants to arrive (from late March) are thought to originate in North Africa and southern Europe, where there is a large post-winter emergence. This is then followed by another wave originating in Spain and Portugal and reaching our shores in May and June. A later influx probably originates from further north within western Europe. Eggs are laid singly on the upper surface of young common nettle leaves (hop, small nettle and pellitory-of-the-wall may also be used as food plants). With the summer warmth these can hatch in a about a week and the young caterpillar will make a small tent at the base of the leaf. As the caterpillar grows so it makes larger and more conspicuous tents, before finally pupating, suspended from the roof of a tent. It is thought that adult Red Admirals mate before their northward journey and this would explain why mating pairs are only seen rarely here in Britain and Ireland. This may also explain the reported southerly movement of adults in July and August. Identification The Red Admiral is one of the most easily recognisable butterflies and has distinctive patterning on theupper surfaces of the wings. Males and females are similar in appearance. When at rest, the underside of the forewing (which has a characteristic pattern) may be obscured by the hindwing. The hindwing itself appears quite dark but has a pale patch on the top edge which is diagnostic.
The use of gardens - results from Garden BirdWatch Results from the BTO/CJ Garden BirdWatch project reflect the pattern of movements that are outlined in the text above, with the reporting rate increasing from May to a peak in August. A very small number of records come from the winter months and probably relate to overwintering adults in southern counties.
Perhaps unsurprisingly, rural gardens have the highest reporting rate and urban gardens the lowest, reflecting the likely availability of nectar sources and caterpillar food plants. Adults may be attracted to gardens by the presence of buddleias and stonecrops.
The widespread distribution and abundance of the Red Admiral across Britain & Ireland is demonstrated by the similar reporting rates for most regions. Click here to see a map showing the distribution of Red Admirals within gardens at the national level, as recorded by BTO/CJ Garden BirdWatchers during 2003.
Click here to see what the region codes on the above graph mean. |
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