All photos: Gordon Redford. Above: May Highflyer
May 2020 is my tenth year of recording moths at Linford Lakes Nature Reserve (LLNR). A variety of moth traps have been used over that time but over the past 3 years access to mains electricity has allowed the use of stronger light sources. Prior to that, lower strength bulbs were used and they were powered by 12V car batteries. From August, 2019 a purpose built moth trap fed from the mains electricity has been in use and has provided most of the May records this year. The moths are attracted to the light source overnight which is over a box which readily permits access and less so egress. The moths settle in the box which is lined with cardboard egg boxes and there they stay until the trap is opened early in the morning when the moths are identified and released unharmed.
In May 2020 the trap attracted 1255 moths of 101 species. This is the highest species number ever recorded there in May over the ten years of recording. 99 was the previous highest number of species recorded in May, in 2017 when 1597 were attracted to the light. To confuse matters further, last year 2,917 moths were attracted to the light in May, more than doubling this year’s total, yet the total number of species recorded then was just 82.
A comparison of the species recorded over the years is interesting too. Of the 101 species recorded this year, 21 were new to the month of May and of these two, Shark and Least Black Arches were new to the site too. Most of the other new ones recorded for May were making early appearances as they have been recorded in June up till now. These records are confirmation of a trend towards earlier emergence by some species due to climate change.
It is well known that the numbers of individual moth species fluctuate over time with peaks and troughs. The May 2020 records have produced the highest May numbers at LLNR for Common Swift (162 – previous recorded high 112 in 2019), Poplar Hawk-moth (87 – previous recorded high 68 in 2017), White Ermine (179 – previous recorded high 92 in 2017), Treble Lines (87 – previous recorded high 52 in 2019) and Common Wainscot (82 – previous recorded high 8 in 2019).
Below: Moths recording their best May numbers this year
At the other end of the scale, the 2020 May records have produced low numbers for some species such as Small Square-spot (3 – from a high of 216 in 2017) and Green Carpet (59 – from a high of 300 in 2017).
In summary then, May 2020 at LLNR has been good for species recorded despite the numbers of moths attracted to the light being lower than in some previous years. It appears that some species are appearing noticeably earlier than in the past. Some species are clearly enjoying a very good May while some others not so.