Hertfordshire & Middlesex Branch

Target Species ~ Grizzled Skipper (Pyrgus malvae)

	Grizzled Skipper Pyrgus malvae © photo: Alan Downie

Status

In 2007 the Grizzled Skipper became a UK Priority Species. It is also Hertfordshire BAP Plan Species. The Grizzled Skipper had been identified in the Thames Regional Action Plan as having Medium Priority status but new knowledge of its distribution and rates of decline thanks to the Millennium Atlas demonstrated why species should be given such urgent higher priority.

A copy of the Species Action Plan can be downloaded here.

Details of the Eastern Region Grizzled Skipper Awareness Campaign here

Behaviour and Identification

Grizzled Skippers are small lively moth-like butterflies, which fly in early spring and dart about busily in warm sunshine, almost disappearing as their wings blur against surrounding flowers and grasses. Sometimes the males soar skywards to court females or chase off rivals. When they perch on prominent twigs, bask with wings open and backs to the sun or take nectar from Bugle or Forget-me-not their distinctive black and white chequerboard wing pattern makes them readily identifiable. In dull weather or at night they rest, often communally, on grass or flowerheads. Although well-camouflaged and hard to spot, for a sharp-eyed naturalist this is a good time to observe and count them

© photo: Chris Pickford	© photo: John Stevens	© photo: John Stevens	© photo: Liz Goodyear

Grizzled Skippers in roosting or semi-roosting position - note the size in relation to the flower heads in particular the forget me knot

Flight Period and Life History

This species is usually single-brooded and adults may appear from late April. By mid-June the flight season has finished and the next generation of eggs have been laid singly on the underside of leaves of foodplants, such as Wild Strawberry, Common Agrimony, Tormentil and Creeping Cinquefoil. The females choose plants growing in warm situations next to bare ground or low-growing vegetation. The tiny yellow caterpillar emerges after about 10 days. It spins a protective tent along the midrib of its leaf, venturing out only to feed or build a new, larger tent. It nibbles the leaf around the edges of its shelter leaving characteristic blotches that are easy to spot. As the caterpillars grow they move to more nutrient-rich taller plants, such as Bramble. They overwinter as pupae inside cocoons of leaves and silk amongst low-growing vegetation. The adult butterflies normally live in small colonies of about 100. Most adults stay within the colony, but some fly up to 1.5km and may be able to fly much further.

Wild Strawberry fragaria vesca © photo: Malcolm Storey BioImages - Virtual Field-Guide (UK)	Wild Strawberry fragaria vesca © photo: Malcolm Storey BioImages - Virtual Field-Guide (UK)	Tormentil potentlla erecta © photo: C.Shepperson

Habitats

Grizzled Skippers flourish in habitats characterised by sunny, sheltered conditions. They need a plentiful supply of spring nectar plants for feeding, an abundance of larval foodplants for breeding and patches of ranker vegetation for perching and roosting. They occupy 3 main habitat types; woodland clearings* (in Hertfordshire this was typified by the colony that used to be found in the glades at Broxbourne Woods) unimproved, often chalky, and usually scrubby grassland (the colony at Aldbury Nowers is located in this type of habitat) and recently abandoned artificial habitats such as gravel pits and railway lines (e.g. the colonies at the disused gravel workings at Waterford Heath).

This butterfly is near the north of its range in Britain. Its strongholds are in the southern English counties, although it also occurs in central England and Wales. It is generally very local and is declining throughout its British range, especially in flat heavily farmed areas. This decline has been especially steep since the 1950s with habitat loss and long cold springs as important contributory factors.

* There are now no known woodland colonies in Hertfordshire

Typical Grizzled Skipper habitat © photo: Andrew Wood	Typical Grizzled Skipper habitat © photo: Andrew Wood
Waterford Heath © photo: Christine Shepperson	Waterford Heath © photo: Christine Shepperson

Distribution in Hertfordshire and Middlesex

The butterfly is believed to be extinct in Middlesex, but is still known in Hertfordshire. When Brian Sawford published The Butterflies of Hertfordshire in 1987, Grizzled Skippers had been recorded in 38 of the 450 or so 2km x 2km squares (tetrads) in Hertfordshire since 1970. By 1995 there were no confirmed sightings at all in Hertfordshire. Fortunately it was found again in 1996 and during a countywide survey from 1998 - 2000 by a team of voluntary recorders co-ordinated by Christine Shepperson from the Herts and Middx Branch of Butterfly Conservation records were confirmed at some traditional sites and two new ones. Between 1996 and 2000 Grizzled Skippers were found, normally in fairly small colonies, in 17 tetrads in the County. It was now clear that this little butterfly, although vulnerable, was still hanging on in Hertfordshire, although at several of its sites it depends on conservation management for habitat maintenance.

In 2005, a second survey was conducted by Andrew Middleton and Liz Goodyear during the winter. Many of the historic sites were revisited and habitat assessments made to determine whether these sites could still support Grizzled Skipper. Two areas stood out as having potential and these were later found to support colonies of Grizzled Skipper. Many sites were no longer felt suitable.

• Table 1 below shows the sites where the butterfly can be found (this list does not include confidential and private sites)
• Table 2 shows the flight dates over recent years.

Distribution in Hertfordshire and Middlesex

Table 1: Sites where Grizzled Skippers colonies have been recorded since 2004 (private sites are not included)

Site/habitat	Tetrad	Last record
Aldbury Nowers	SP91L	2010
Tring Park	SP91F	200?
Telegraph Hill	TL12E	2004
Waterford Heath (North and South Pits)	TL31C	2010

Table 2: Flight dates 1996 - 2010

Flight Dates	Year
23 April - 22 June	2010
19 April - 13 June	2009
03 May - 10 June	2008
19 April - 22 May	2007
02 May - 24 June	2006
30 April - 22 June	2005
09 May - 10 June	2004
22 April - 15 June	2003
?? May - 1 June	2002
20 May - 25 June	2001
07 May - 16 June	2000
02 May - 15 June	1999
14 May - 19 June	1998
13 April - 8 June	1997
27 April - 15 June	1996

Historic distribution

Click on map for details

SYMBOL	DATE	REFERENCE SOURCE
	1998-2004	Indicates records sent to Christine Shepperson or Jez Perkins
	1995-2001	Additional sites where Grizzled Skipper were found 1995-1999 taken from the Herts & Middx Butterfly Report for 1999 - John B. Murray & Rob Souter
	1970-1987	Indicates records taken from Butterflies of Hertfordshire - Brian Sawford 1987 or The Butterflies of the London Area - Colin Plant 1987
O		Indicates sites that were thought might have potential for Grizzled Skipper colonies

Acknowledgements

Much of the original text on this page was published in Wildlife Matters, the newsletter of the Herts & Middx Wildlife Trust and the author thanks the Trust for permission to use the material on this website.
Christine Shepperson
March 2002

(However much has changed since the article was written, new sites have been found but others have been lost. The text has been edited to reflect this ~ March 2010)