The Annual Big Butterfly Count Has Finished And The Local Results Are Much Better Than Last Year.
The Big Butterfly Count is one of the largest citizen science projects with over 100,000 people spending 15 minutes counting butterflies and day flying moths they can see in their gardens and around other sites. The survey records 18 easy to identify butterflies and 2 day flying moths. Running in late July and early August since 2010, the Big Butterfly Count provides important scientific data on the health of our butterfly and day flying moth populations and, like canaries in a coalmine, they are an indicator of wider environmental health.
There were nearly 200 counts recorded in the Sid valley and we have been able to collate the data from 158 of them. Having counted all the recorded butterflies, we then have to calculate the average figures per count to enable comparisons with other years and the national picture.
As has always been the case in past years, more butterflies were seen per count in our valley compared to the national average. This year our 158 counts recorded 1,992 butterflies or 12.61 per count. The 181,000 national counts recorded nearly 1,900,000 butterflies, that is an average of 10.43 per count.
Last year was not a good year for butterflies, the poor spring weather was mainly responsible for one of the worst sets of butterfly count data in fifteen years of counting. This year there is much better weather and so better news, the national figure has increased by 48%, and our local count data shows exactly the same gain.
Nearly three quarters of the local counts were in gardens, the rest were mainly out in farmland or in local nature reserves. Perhaps unsurprisingly, more butterflies are seen out in the countryside than in the town’s gardens, but it might surprise you that the ratio is nearly 4:1 in our counts, 24.53 butterflies per countryside count compared to 6.86 per garden count.
As the majority of the national counts are in large towns and cities the national count is always dominated by two of the Cabbage species, the Large and the Small Whites, but our local counts are dominated by Gatekeepers and Meadow Browns, countryside species which also manage to come into the middle of our small town.
The Large White is our third most common, but this year’s surprise was the Common Blue which came in fourth in the local counts. This small beautiful butterfly usually hovers (apologies for the pun) around the 8-10th rank, but it has had a very good year here and there are many of them about.
They are probably benefiting from efforts to allow wild flowers to grow in grassy areas because the main food plant for their caterpillars is Bird’s-foot Trefoil, a small yellow pea flower that is growing in abundance on uncut verges and areas such as Alma Field and the SVA’s Margaret’s Meadow in The Byes. Many people talk about having flowers in their gardens for butterflies and bees, but you have to have the caterpillar food plants first.
One puzzling absence this year is the day flying Silver Y moth. Usually quite common in the grassy meadows, only one moth was recorded in the 158 counts this year, 74 were recorded in last year’s 170 collated counts. Actually a migrant from France, they do not seem to have taken the trouble to fly across the channel this year.
The adult butterfly populations start to die off as August progresses, but hopefully this tear’s increased population have laid enough eggs for even more butterflies and moths next year.
There will be a fuller report on the Sid Valley Biodiversity Group website by the end of the month.
Ed Dolphin
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