Red admiral Vanessa atalanta    
Family : Nymphalidae Tribe Nymphalini
 
 
What do they look like?
A large, distinctive butterfly with both sexes alike. In flight red admirals are unmistakable:  the upper surfaces of the forewings have a very dark brown background, almost black, with a bright red stripe on each wing and white patches above the stripe. The hindwings are dark brown with broad red edges. The underside of the forewing also has a distinctive red and white patterning but when the butterfly is resting this can be obscured by the hindwing underside, which has a dark, mottled appearance, but is full of tiny spots of colour when seen close up. The wingspan is between 64 and 72mm for males; 70 to 78mm for females.
 
Where are they found (in Britain and Ireland)
All Britain and Ireland
 
What is their preferred habitat outside gardens?
Red admirals are strong flyers with a widespread foodplant and can therefore be found in almost any habitat.
 
Resident or migrant?
Spring and summer migrant. Overwintering now occurring in far south of England (see below).
 
When to see them?
These are long-lived butterflies that migrate annually in waves from continental Europe throughout the spring and summer. A peak time is in May and June, then again in late summer and early autumn as a new brood of locally bred adults emerge. However, recently red admirals have been seen throughout the year in the UK, particularly in the south, with several sightings now being reported in the winter. Some of these may be early migrants but it seems that with climate change some individual butterflies can survive the winter and form a small resident population in the far south of England.
 
What happens in winter?
There is a partial re-migration with many of the new brood of butterflies that have hatched in the UK heading south across the English Channel in the autumn. Others will die and a few survive the winter, as noted above.
 
 
Flowers they take nectar from
The butterflies feed mainly on blackthorn, brambles, buddleja, common fleabane, hawthorns, hemp-agrimony, thistles, wild privet and wild teasel. They also use sap and in the autumn ivy, Michaelmas-daisies and rotting fruit2..
 
How are they doing?
As they are a migrant butterfly, red admiral numbers fluctuate from year to year. But the overall trend appears positive with the 2022 State of UK butterflies report  showing a statistically significant increase in numbers (234%) and distribution (14%) since 1976; these are similar to the 2015 findings3..
 
 
Other interesting facts
It is thought that adult red admirals mate before their northward journey, and that this explains why mating pairs are only seen rarely in the UK. However males do sometimes exhibit territorial behaviour and their mating behaviour is still a subject of research. Whether the recent overwintering will affect their mating behaviour is another interesting question.
 
 
References
 
1.  Biological Records database
 
2.  UK Butterflies website
 
3. State of UK butterflies report 2022
 
  
 
 
Page written by Judy Skinner, reviewed and compiled by Steve Head
What do the early stages look like?
 
Red admiral eggs are laid singly, but often several in the same nettle patch.  They are ribbed and bright green, darkening later.
 
The first stage caterpillars are a pale olive colour with a darker head and about 1.5mm long. Growth is rapid and they reach full size (35mm) in three to four weeks, after the fourth moult. They become much darker soon after the first moult and develop bristly spines all over their bodies. There is a pale form as well. The caterpillar lives in a small “tent” that it makes by folding leaves of the foodplant and binding them with silk thread. Several tents are made throughout the larval stage and searching for these can be a good way to find the caterpillars.
 
The pupa is formed within the last larval "tent".  It is dark brown, with patches of metallic golden colour.
 
What do the caterpillars eat?
Their main foodplant is common nettle Urtica dioica. Small nettle Urtica urens, hop Humulus lupulus, and pellitory-of-the-wall Parietaria diffusa are also used1.
 
What do they look like?
A large, distinctive butterfly with both sexes alike. In flight red admirals are unmistakable:  the upper surfaces of the forewings have a very dark brown background, almost black, with a bright red stripe on each wing and white patches above the stripe. The hindwings are dark brown with broad red edges. The underside of the forewing also has a distinctive red and white patterning but when the butterfly is resting this can be obscured by the hindwing underside, which has a dark, mottled appearance, but is full of tiny spots of colour when seen close up. The wingspan is between 64 and 72mm for males; 70 to 78mm for females.
 
Where are they found (in Britain and Ireland)
All Britain and Ireland
 
What is their preferred habitat outside gardens?
Red admirals are strong flyers with a widespread foodplant and can therefore be found in almost any habitat.
 
Resident or migrant?
Spring and summer migrant. Overwintering now occurring in far south of England (see below).
 
When to see them?
These are long-lived butterflies that migrate annually in waves from continental Europe throughout the spring and summer. A peak time is in May and June, then again in late summer and early autumn as a new brood of locally bred adults emerge. However, recently red admirals have been seen throughout the year in the UK, particularly in the south, with several sightings now being reported in the winter. Some of these may be early migrants but it seems that with climate change some individual butterflies can survive the winter and form a small resident population in the far south of England.
 
What happens in winter?
There is a partial re-migration with many of the new brood of butterflies that have hatched in the UK heading south across the English Channel in the autumn. Others will die and a few survive the winter, as noted above.
 
 
What do the caterpillars eat?
Their main foodplant is common nettle Urtica dioica. Small nettle Urtica urens, hop Humulus lupulus, and pellitory-of-the-wall Parietaria diffusa are also used1.
 
Flowers they take nectar from
The butterflies feed mainly on blackthorn, brambles, buddleja, common fleabane, hawthorns, hemp-agrimony, thistles, wild privet and wild teasel. They also use sap and in the autumn ivy, Michaelmas-daisies and rotting fruit2..
 
How are they doing?
As they are a migrant butterfly, red admiral numbers fluctuate from year to year. But the overall trend appears positive with the 2022 State of UK butterflies report  showing a statistically significant increase in numbers (234%) and distribution (14%) since 1976; these are similar to the 2015 findings3..
 
 
Other interesting facts
It is thought that adult red admirals mate before their northward journey, and that this explains why mating pairs are only seen rarely in the UK. However males do sometimes exhibit territorial behaviour and their mating behaviour is still a subject of research. Whether the recent overwintering will affect their mating behaviour is another interesting question.
 
 
References
 
1.  Biological Records database
 
2.  UK Butterflies website
 
3. State of UK butterflies report 2022
 
  
 
 
Page written by Judy Skinner, reviewed and compiled by Steve Head
What do they look like?
A large, distinctive butterfly with both sexes alike. In flight red admirals are unmistakable:  the upper surfaces of the forewings have a very dark brown background, almost black, with a bright red stripe on each wing and white patches above the stripe. The hindwings are dark brown with broad red edges. The underside of the forewing also has a distinctive red and white patterning but when the butterfly is resting this can be obscured by the hindwing underside, which has a dark, mottled appearance, but is full of tiny spots of colour when seen close up. The wingspan is between 64 and 72mm for males; 70 to 78mm for females.
 
Where are they found (in Britain and Ireland)
All Britain and Ireland
 
What is their preferred habitat outside gardens?
Red admirals are strong flyers with a widespread foodplant and can therefore be found in almost any habitat.
 
Resident or migrant?
Spring and summer migrant. Overwintering now occurring in far south of England (see below).
 
When to see them?
These are long-lived butterflies that migrate annually in waves from continental Europe throughout the spring and summer. A peak time is in May and June, then again in late summer and early autumn as a new brood of locally bred adults emerge. However, recently red admirals have been seen throughout the year in the UK, particularly in the south, with several sightings now being reported in the winter. Some of these may be early migrants but it seems that with climate change some individual butterflies can survive the winter and form a small resident population in the far south of England.
 
What happens in winter?
There is a partial re-migration with many of the new brood of butterflies that have hatched in the UK heading south across the English Channel in the autumn. Others will die and a few survive the winter, as noted above.
 
 
What do the early stages look like?
 
Red admiral eggs are laid singly, but often several in the same nettle patch.  They are ribbed and bright green, darkening later.
 
The first stage caterpillars are a pale olive colour with a darker head and about 1.5mm long. Growth is rapid and they reach full size (35mm) in three to four weeks, after the fourth moult. They become much darker soon after the first moult and develop bristly spines all over their bodies. There is a pale form as well. The caterpillar lives in a small “tent” that it makes by folding leaves of the foodplant and binding them with silk thread. Several tents are made throughout the larval stage and searching for these can be a good way to find the caterpillars.
 
The pupa is formed within the last larval "tent".  It is dark brown, with patches of metallic golden colour.
 
 
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