Early publications on Cheshire butterflies give few details as to the abundance of the Common Blue, although Day (1903) specifically commented that it was “common in greater part of Cheshire, except in the east, where it is seldom seen near the large towns”. Subsequently there was little information published on the status and distribution of this butterfly until the period from 1975 to 1982 when a systematic study by Rutherford (1983) reported it as “widespread and often common, but restricted by habitat and food-plant”.
Since the formation of the Cheshire & Peak District branch of Butterfly Conservation in 1985 extensive recording work has shown that where suitable habitat still exists the Common Blue remains a fairly common and widespread resident. Many sites in the county, especially in lowland areas, have however been lost to intensive farming methods and general tidying-up of the countryside. In the Pennine hills, east of the Macclesfield Canal, the distribution has always been patchy due to fewer areas with its favoured foodplants. Data extracted from the Cheshire Butterfly Recording Scheme shows that since 1985 this insect has been recorded in 417 of Cheshire’s 688 tetrads (2km x 2km squares) – 60% of the total.
The Common Blue breeds in a range of habitats and will quickly colonise new sites whenever suitable conditions occur. Favoured habitats are on unfertilised grassland, waste ground, derelict industrial land, embankments, riversides, roadside verges, woodland edges or wherever its foodplants occur. This butterfly uses a wide range of foodplants in Cheshire including Common Bird’s-foot Trefoil (Lotus corniculatus), Greater Bird’s-foot Trefoil (L. uliginosus), White Clover (Trifolium repens) and Common Yellow Trefoil (T. dubium). Records show that the Common Blue is normally double-brooded in the county with the first emergence peaking in early June and the second brood with maximum numbers seen from early August to mid-August. Occasionally, following warm summers, there is a small partial third generation. From the limited data available it would appear that in the harsher environment of the eastern hills there is usually just a single emergence. Earliest county sighting was at Ditton on 16th April 1993 and the latest in Delamere Forest on 23rd October 2001.
It is the male butterflies that are most frequently observed as they establish territories, search for females, bask and take nectar - they tend not to wander beyond their breeding grounds. Females, with their subdued colouring, are less conspicuous and except when egg-laying or feeding remain hidden amongst vegetation. Shortly before dusk the Common Blue can often be found in sheltered hollows roosting communally in the head-down position amongst clumps of tall grasses.
In parts of the U.K. colonies can often consist of several hundred adults, but in Cheshire there are few sites that support such numbers. Common Blue numbers can, however, vary considerably from one year to another, largely due to weather conditions. In the last 10 years counts of 100+ individuals have been restricted to the following localities - Hale Shore (max. 135 on 4th August 2003), Arclid Sand Quarry (max. 250 on 30th May 2004), Rixton Claypits (max. 141 on 7th June 2004), Chorlton (max. 135 on 5th August 2006), Astbury Mere (max. 250 on 2nd August 2010), Pickering’s Pasture (max. 200 on 7th August 2010) and Woolston Eyes (max. 201 on 19th August 2010).
Due to the continual pressures on the remaining open spaces in the county, together with the efficiency of modern farming methods, there are now fewer sites available to support substantial populations of the Common Blue. Nevertheless, with its ability to quickly establish new colonies in even small areas of suitable habitat this butterfly remains a reasonably common insect of the Cheshire countryside.
Day, G.O. (1903). A list of Lepidoptera found in the counties of Cheshire, Flintshire, Denbighshire, Carnarvonshire and Anglesey.
Rutherford, C.I. (1983). Butterflies in Cheshire 1961 to 1982.
Written by Barry Shaw for News, the Cheshire and Peak District Branch of Butterfly Conservation magazine.