Butterflies in the Stevenage area

Long-extinct species and very rare immigrants

The species described in this section are either those which became presumed extinct since before the survey started in 1993 or immigrants which very rarely arrive in this part of the country. The biggest losses are the fritillaries, like the High Brown Fritillary. The decline started in the 1950s and all apart from the Silver-washed Fritillary have not recovered. The practice of woodland coppicing largely ceased after the war and taller vegetation took over the areas where the low-growing foodplants (Violet family) used to thrive. The loss of the Marsh Fritillary, being a butterfly of wet habitats, however, was due to damage and loss of meadows. The Wall butterfly is now extinct but was present until 1999 so this species account is described elsewhere. The Camberwell Beauty is a fairly regular visitor in the eastern coastal counties but mostly in low numbers and very few reach as far as Hertfordshire.

Scarce Swallowtail Iphiclides podalirius

The Scarce Swallowtail is believed to be a very rare immigrant although some sightings may be releases from captive-bred stock.

In the Stevenage area, a female was reported egg-laying on Cherry Plum at Langley in the 1970s (John Tomkins, personal communication.). However, there is some confusion as apparently the same observation was made on 14 June 1992 (Wood 2016).

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Pale Clouded Yellow Colias hyale

A very rare immigrant and numbers have been much lower since the middle of the 20th century.

According to Foster's report in 1934 the best years were 1877 and 1900. In 1900 it was abundant even in town streets. A specimen was seen in Hitchin in 1933, another at Aldbury in 1946 (Fryer). Birdsall caught a female and two males in 1947 at Walkern. A specimen was reported from the Hitchin area on 29 May 1974 (Bell 1977) and another at the Warren Springs area in Stevenage (as it was then known) on 18 September 1976 (Waterton 1982 and Sawford). This species and the Berger's Clouded Yellow are very similar in appearance but the Pale Clouded Yellow is known to be far more common.

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Large Tortoiseshell Nymphalis polychloros

Extinct as a resident since about 1950 but there were huge fluctuations in abundance before then. Immediately before the steep decline in 1949 the butterfly was abundant in many areas perhaps aided by the warm summers during that time. It is a mystery why the butterfly has disappeared and the very occasional sightings nowadays are very likely to be immigrants as there have been no reports of any immature stages (Thomas & Lewington) .

Matthews reported two or three a season in Stevenage around 1900 according to the 1902 report (Gibbs) but had already indicated a decline in abundance by then. There is only one report since Matthews' time: at Watery Grove by Nigel Agar on 10 April 1981 (Waterton 1982 and Sawford).

More details on the UK Butterflies website

Camberwell Beauty Nymphalis antiopa

A scarce immigrant with usually a few sightings each year in the country especially on the eastern side where they normally arrive from Scandinavia. The last great year was 2006 when it was seen throughout the Britain. However, it is unable to breed here and most individuals are seen in late summer. Although some adults survive the winter and are seen in early spring there are so few that finding a mate is almost impossible.

There are no reports in the Stevenage area until the 1970s. A specimen was found feeding on sap from dying elm in Lodge Way, Stevenage in August 1976 (Sawford, cards). 1995 saw a spectacular invasion in England with several sightings in Hertfordshire. Some were seen in Hitchin at the 'buddleia forest' (Murray 1996). There were some survivors in 1996 with a report from Knebworth Park by Ken King on his transect on 20 April (Murray 1997). In 2006 there was one at Knebworth Station on 25 August by Brian and Elizabeth Nicholls (Wood & Murray). In 2007, one was reported in Stevenage (Wood 2016).

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Small Pearl-bordered Fritillary Boloria selene

This is a butterfly now mostly found in the west and north of Britain although it was widely distributed at the start of the 20th century. Loss of habitat as a result of cessation of woodland coppicing is largely to blame for the colonies dying out in the south and east.

Matthews reported this butterfly as common in the Norton Green woods in around 1900 (Gibbs) but had disappeared by the 1930s (Foster 1934).

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Pearl-bordered Fritillary Boloria euphrosyne

More widespread than the Small Pearl-bordered Fritillary with quite a few colonies in the south-east of England. However, populations have declined in the last 50 years or so due to degradation or loss of habitat in woodlands following the termination of coppicing.

Matthews describes this species as common in the Norton Green woods in around 1900. This is the most abundant of the Hertfordshire fritillaries, often flies in considerable numbers in woodlands in May and June (Gibbs). It was still common in the 1940s: Roger Ferry caught 18 specimens on 9 May 1948 at the Knebworth woods (Ferry's collection at the Mill Green Museum). Rev Greenbaum of Walkern Rectory writes that it 'was flying in numbers in the surrounding woods in 1945 (Foster 1946). S. R. Bowden saw plenty in Knebworth Wood on 10 June 1951 (Bowden 1953) but no reports from this area since then. The last colony in the county appears to have died out at Bramfield Woods in the late 1970s (Murray 1996).

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High Brown Fritillary Argynnis adippe

This species has declined over 90% since 1976. The most probable cause is the cessation of woodland coppicing and preventing the butterfly's food-plant to thrive in open areas. There could well be other factors as the species is also found in more open areas like moorland in the north-west of the country.

Matthews did not report the presence of this species in around 1900 but Ray Palmer noted several in the 1920s in Knebworth woods which he described as numerous on 20 July 1929 (Ray Palmer diaries 1922-1969 at the North Herts Museum). It was common there in the 1940s when Roger Ferry caught 12 individuals on 7 July 1946 when it was 'abundant' (Ferry's cards at the Mill Green Museum). S.R. Bowden noted many on 9 May 1950 at the site (Bowden 1950). It was also present in reasonable numbers in the 1940s at St Johns Wood near Walkern (Birdsall). In 1971, John Butter introduced 120 eggs in Whomerley Wood and Monks Wood without success (Butter).

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Marsh Fritillary Euphydryas aurinia

The Marsh Fritillary is a butterfly of wet habitats. The loss and/or drainage of meadows as a result of intensive agriculture after the war is a major cause of the widespread decline in the last 50 years or so.

William Hill found a specimen at Burleigh Heath (probably one of the fields north or south of Burleigh Farm) in 1881 and the butterfly was also taken at Knebworth Wood at around this time (Durrant). There are several reports of the butterfly in the 1940s in the Knebworth woods area but appears to have disappeared by the end of the decade.

More details on the UK Butterflies website