Worcestershire Record No. 27 November 2009 pp. 12-13

Garth Lowe

This year finally bucked the trend of very poor summers even though two of the summer months June and July produced figures of 91.3 and 106.3 millimeters of rain! The short spells of warmer weather allowed most species to increase their numbers compared with previous years. Total sightings were 2564, but to find a better year we have to go as far back as 1996 with 3507!

Although butterflies fared better this year, one species the Meadow Brown, did show a fall, dropping back to a similar figure found in 2006. The wet July did delay hay making in Big Meadow, but with a much lower rainfall in August and September this was then made possible, unlike last year when the meadow was left untouched. Another change in the grazing regime was the introduction of the small Dexter cattle. These went into Papermill Meadow first, and then into Big Meadow shortly after removing the hay. It is now thought light grazing should take place over a longer period on the various pastures, so its effect will have to be assessed over the next few years. On the surface, management of the meadows has hardly changed over the period of monitoring, but sightings of Meadow Browns over the flight period have now halved.

Another big disappointment was the absence of the Dingy Skipper, which now looks as if it will join the Small Heath as another species that may never be seen here again. The Orange Tip also did quite badly, and only appeared in small numbers compared with other years, when three and four times this figure have been recorded. The Red Admiral and Small Tortoiseshell were only seen in single figures but the latter did show a small increase. In late summer it is the fallen crop of fermenting apples that usually brings in the red admirals, Commas and Speckled Woods to take advantage of natures free tipple! Why do these species get intoxicated and not the Green-veined or Large Whites that are also still around?

On a more positive note it was good to see many more of the 24 species having a much better year. The large invasion of Painted Ladies earlier in the year was also reflected here, with the largest number seen since 1996, when a similar occurrence took place. The increase of the White Admiral was rewarding, having now been seen in five consecutive years, after an absence from 1997 to 2002. The Speckled Wood and Green-veined White numbers were the highest since 1998, making this a very long period in which to recover.

It was the Ringlet that had a very productive year, and had the highest total sightings since records started. The reasons for this might be that it seems to cope with damper summers better than most of the others, so that given an ideal summer, such as the one just gone, it was able to substantially increase its numbers. The Small Skipper also did very well and was seen in increasing numbers, but can also be seen to have rather fluctuating figures from year to year.

The Large Skippers, seem to be an anomaly as their numbers have been fairly small whatever the weather, with a highest figure of 43 in 1989 and a lowest of five in 2008. The Marbled Whites this year were still present showing a small increase, but only a third of that for 2006. This is one species that may change with extra grazing, as it mainly occurs in the Papermill Meadow where the cattle will spend more time.

Altogether it was a pleasure to see an increase in a lot of species in the reserve, with the hope that the warmer drier climate change will reach us eventually, and not just parts of the rest of the world!

Table 1. Total butterfly sightings at Knapp and Papermill, 1992-2009, April to September. * Some missing weeks 2003, and one week 2004