General Distribution and Status

The White Admiral is locally common south-east of a line between Devon in the west and Lincolnshire in the east although it is scarcer in eastern England and with scattered colonies elsewhere. In the early part of the 20th century populations were restricted to the extreme south of England but an expansion started in the 1920s and by the 1940s assisted by the fine weather in that decade it spread as far as Lincolnshire. It is known that warm weather in June may have a beneficial effect on the butterfly, but research on the effect of climate change on the White Admiral also indicates that mild winters probably have a negative impact (Palmer et al.) possibly because the overwintering larval hibernaculum is more vulnerable to predators or parasites in mild conditions. However, one other likely reason for the spread is the change or lack of coppicing in woodlands which facilitated growth of honeysuckle to a more suitable height. Although there had been continued expansion until the 1970s a notable decline in numbers and range has occurred since then (Brereton et al., Fox et al., 2015). Some possible reasons have been cited. Some forestry practices involve removing honeysuckle as it is regarded as a weed by some foresters (Asher et al.). Deer browsing of the plant is another possibility. In Hertfordshire and Middlesex, although some expansion occurred up to the mid 1990s fortunes have reversed since the beginning of the century and is a major concern. It is now a target species.

UK distribution map
UKBMS Species summary

Habitat Requirements

This species is a butterfly of deciduous woodlands where its hostplant Honeysuckle Lonicera periclymenum grows in shady situations but sunlit rides are required for males establishing territories.

Larval Foodplants

Honeysuckle Lonicera periclymenum.

Adult Food Sources

Bramble Rubus fruticosus agg. (50), Ergot (fungus) (30), Ground/mud/road surface (7).

Historical Records

The first record in Hertfordshire was in 1916 when Mr C. H. Jackson caught a specimen at Symonshyde Great Wood in July, but it is likely that the White Admiral was present before then (Sawford). Quite a few reports in the 1930s came from Broxbourne Woods, Bricket Wood and Ashridge (Hodgson). In the 1940s, the butterfly was spreading north so that it was now appearing in the Knebworth Woods area where Roger Ferry caught 11 specimens in 1946. Ferry also notes that Mr McNichol found pupae at Gunnels Wood on 3 July in the same year. Rev. Greenham saw several at Box Wood in 1943, the butterfly having colonised there the year before and it was still doing well at St. John's Wood in 1953 (Birdsall). It is unclear from the local journals if there was any trend developing in the following 20 years or so but according to Sawford the butterfly became scarce between the 1950s and the early 1970s. The warm and dry summers of 1975 and 1976 caused a sharp increase in numbers at a number of sites (Sawford).

Local Distribution and Abundance

As indicated on the map, the butterfly is only recorded from the Knebworth Woods area. After an absence in 2015 and 2016, two records were reported in 2017, both on 13 July. One was also seen on 1 July 2018 at Norton Green Common but sadly none were discovered in 2019, 2020 and 2023 although two sightings were reported in 2024, both in the Knebworth Woods complex on 27 June and 1 August. In the past, the favoured spots were at the northern end of Wintergreen Wood by the public footpath and the southern tip of Norton Green Common. Another reason for the paucity of records is that some of the patches of bramble on which the butterfly used to feed, have now been overwhelmed by other vegetation. The last records at these localities were in 2011. There was an interesting sighting of this butterfly in St Mary's churchyard at Aston on 20 July 2020 about a mile distant from any woodland, High Wood and Astonbury Wood so these woods will be worth investigating for any colonies. Every report thus far consists only of singletons.

Only the Knebworth Woods transect yielded any records.

Knebworth Woods transect 2017-2024

One record on 1 August 2024 between The Firs and Newton Wood.

Life History

Earliest date: 17 June 2014 at the Firs, Knebworth Woods
Latest date: 29 July 2004 at Norton Green Common

Usually only one generation a year is produced with emergence from late June until early August. A partial second brood is sometimes produced in warm summers as in 2006. Females lay eggs singly on the upperside of a honeysuckle leaf in slightly shady situations. Larvae feed on the tip and sides of a midrib of a leaf before forming a hibernaculum for the winter. Feeding is resumed in the spring. When fully grown, a pupa is formed suspended from a leaf or stem.

Behaviour/Observation notes

Although the White Admiral spends some time in the tree canopy like the Purple Emperor, males often fly at lower levels in sunlit rides. Both sexes will occasionally come down to feed. If you know where to find the butterfly, with some patience you may be lucky to find it basking or feeding on flowering brambles with its wings wide open to provide good photographic opportunities.

Variations/Aberrations

The most common aberrations of this butterfly relate to the extent of the white bands, namely ab. nigrina and ab. obliterae. The former is where the white bands are completely absent and the latter is one with just a few white patches. Colin Everett found an ab. obliterae specimen in Bricket Wood on 9 July 2010.
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