Spotlight on Cheshire butterflies: the Speckled Wood (Pararge aegeria)

The present status of the Speckled Wood in Cheshire is as an abundant and widespread resident, although this has not always been the case. During the twentieth century Ellis (1903) described it as “occurring only very sparingly – not found in East Cheshire”, whilst Mansbridge (1940) stated that it “seems now to have become very scarce”. A first indication that this butterfly was extending its range in the county was when Smith (1948) reported it as “locally common”. Later work by Rutherford (1983) found it “widely distributed, but with a south-western bias”.

Even accepting that there was very little systematic recording undertaken at those times, the butterfly has obviously undergone a tremendous expansion in its range in subsequent years. In 1985 the Speckled Wood was only the 11 th most widely distributed butterfly in Cheshire, but by 2002 it had become the 4 th – behind the Small Tortoiseshell, Peacock and Green-veined White.

This range expansion has been especially noticeable at sites in the north and east of the county where it was previously unknown. In addition, since the mid-1990s, small numbers have even been recorded from the Pennine foothills where conditions would normally have been considered unsuitable for this insect.

Fairly typical of the improving fortunes of this insect are reflected in my local 10km square of SJ88 (Wilmslow). Prior to 1990 the Speckled Wood was not found in this area, but the following Table illustrates how rapidly it has become established during recent years.

Traditionally the preferred habitat of the Speckled Wood in Cheshire has been in shady woodland sites where small areas of sunlight filtered through the canopy. More recently the butterfly has been just as likely to be encountered along hedgerows or in parks and gardens. Several reasons have been suggested for the recent spread in the range of this butterfly with the decline in coppicing being frequently quoted, but the dramatic range extension in Cheshire has only occurred over the last 15 years – long after the decline in coppicing. It seems likely that global warming could be partially responsible for the recent expansion, but the changes appear to have occurred far too quickly for there not to be other contributory reasons.

The Speckled Wood is unusual amongst British butterflies in that it overwinters in different stages of its life cycle. The earliest butterflies seen in the spring are those that have spent the winter as pupae, whilst it is several weeks later before those that wintered in the larval stage are recorded. There is, therefore, a complicated pattern of emergence dates throughout the season making it difficult to ascertain whether two or three broods have occurred in any particular year. In most years it is, however, possible to see this species at any time between late March and early October.

Whilst the Speckled Wood is normally only seen in small numbers it does form sizeable colonies at woodland sites. It is likely that the majority of insects seen are the males that spend considerable amounts of time patrolling their territories, whereas the females are less conspicuous spending much of their time feeding from aphid honeydew in the tree canopy.

References:

Day, G.O. (1903). A list of Lepidoptera found in the counties of Cheshire, Flintshire, Denbighshire, Carnarvonshire, & Anglesea”

Mansbridge, W. (1940). The Lepidopterous Fauna of Lancashire and Cheshire. A revision of the Ellis list of 1890.

Rutherford, C.I. (1983). Butterflies in Cheshire 1961 to 1982. Proceedings of the Lancashire and Cheshire Entomological Society.

Smith, S.G. (1948). The Butterflies and Moths found in the counties, Cheshire, Flintshire, Denbighshire, Caernarvonshire, Anglesey and Merionethshire.

Written by Barry Shaw for News, the Cheshire and Peak District Branch of Butterfly Conservation magazine.