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NEWSLETTER No. 15 -  Summer 1986

WEST MIDLANDS BRANCH, BUTTERFLY CONSERVATION

 

Butterfly Monitoring at Knapp & Papermill Reserve 1985

As far as the weather was concerned 1985 proved to be the exact opposite to the previous year's warm, sunny Summer which was idyllic for butterflies. To make the weekly counts the conditions need to be a minimum of 11°C in full sunshine or above 17°C if there is total cloud cover. In 1984 the average weekly temperature was 19.5°C but in 1985 this dropped to 17°C and this, combined with the damper conditions reduced in most species the numbers of butterflies and their flight periods. The maximum species noted on any one day was only fifteen seen on 17th August, whereas in 1984 it reached nineteen on 22nd July. Two butterflies not seen in 1985 were the High Brown Fritillary and the Wall Brown, but a bonus was the sighting on two occasions of White Admiral, a species which appears to be increasing its range. Interesting to compare were the actual maximum numbers of certain common species seen on one complete walk, varying in relation to whether their flight period coincided with a better spell of weather.

 

Species of butterfly that were down significantly were the Meadow Brown, Small Copper, Small White and Common Blue, whilst numbers of Ringlet and Hedge Brown were similar, and totals for the Green-veined White were up.

The grazed part of Papermill meadow again had the highest number of species seen throughout the Summer, a total of eighteen compared with twenty-five in 1984. The management of this old grassland is to graze only three quarters of the area between Spring and Autumn so that a different quarter lies ungrazed every year.

Those butterflies seen in very low numbers are tabulated below with the maximum seen on one day:
 

It is pleasing to record these species but it is surprising how they manage to hang on. The table below shows what effect the colder, wet Summer had on the ten most sighted species:
 

Gareth Lowe.