2008 BUTTERFLY REPORT

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RUNNING HEAD

47

2008 BUTTERFLY REPORT ROB PARKER From the start, 2008 was destined to be a poor butterfly season. The previous wet year left low numbers of insects passing the winter of 2007/2008 as eggs, larvae, pupae or adults. Although much of that winter was relatively mild, the frosts of 23/24/25 March further reduced the number of survivors. Most species had a poor year, and a shortage of migrants suppressed variety as well as total numbers. Many observers commented that it was the worst season they could remember. Nationally, Butterfly Conservation declared 2008 the worst butterfly year for 25 years. Fortunately, there were a few bright spots to offset this gloomy assessment. Weather The winter months were mild judged by average temperatures, but spoiled by snow in March. Thereafter, mean temperatures for East Anglia were slightly above historic averages, subsiding to average by autumn (See table below). Spring was wet, and summer continued wet, with sun and temperatures close to normal. The rain and cloud reduced the number of days suitable for flying and mating, and butterfly activity was generally low. Table 1. 2008 Weather for East Anglia

Season

Winter 07/08 Spring Summer Autumn

Mean Temp Anomaly Sunshine Anomaly Rainfall

Anomaly

°C

°C

hrs

%

mm

%

5Â7 9Â3 16Â4 10Â1

2Â0 1Â1 0Â8 0

234 492 558 320

139 111 98 108

135 195 191 383

94 141 124 109

Source: www.metoffice.gov.uk/climate/uk Anomalies are measured against the 1961 to 1990 averages. A review of the number of days in spring when the sun shone in conjunction with temperatures of above 15°C (at the SNS weather station in Boxford) reveals that the maximum temperature remained below 15°C for the whole of March, and that only five days in April achieved that temperature without some rain. Unsurprisingly, transect walkers had great difficulty in getting any walks in within the stipulated weather criteria. May was slightly better, but there were still twelve days that failed to meet the basic butterfly flight criteria, delaying the emergence of species that had passed the winter as pupae. In June there were 13 days that provided little opportunity for flight, or pairing.

Trans. Suffolk Nat. Soc. 45 (2009)


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2008 BUTTERFLY REPORT by Suffolk Naturalists' Society - Issuu