I have finally gone through my records from 2014-2021 to tot up catch by species for each year. Apart from being able to see some trends the other stand out insight was how far out my impression of how common certain species had been in previous years.
In particular I over-estimated previous catches of some of the species which to me were more iconic. So things like Privet Hawk and Buff-tip have been more or less stable rather than in decline as I’d believed before I went back to do the yearly counts.
Looking at previous years I can also see that some species that weren’t common or absent in 2021, had varied also in the past. I’ve also excluded from the analysis those species that were in low numbers to start with.
The ones that look as if there actually are trends are:
Heart & Dart 2021 only 31. (2020 = 179, 2019 = 272)
Treble-lines seems to have quadrupled in numbers in the last 3 years.
Small Elephant Hawk seems to be increasing in the last few years.
Small Square-spot 2014-2017 averaged 20 a year. There were then none 2018-2020. 10 appeared in 2021.
Buff Arches, average 2014-2018 10 per year, since average is only 1 a year.
Riband Wave has consistently declined year by year, 2014 = 64, 2021 = 25.
Flounced Rustic numbers more than doubled for 2020-2021.
Dot Moth has declined, 2014 = 34, then numbers went down, 20219 & 2020 none, 2021 = 2.
White-point, as might be expected has increased. From 2014 = 3 to 2020 = 27 this was more or less a consistent increase. 2021 was 118!
Common Wainscot was more or less stable 2014-2016 at av 50 per year, 2017-2019 it was consistent at 190 per year, 2020 hit 546 and 2021 it was 894. That means it over took Large Yellow Underwing numbers for the first time.
Large Yellow Underwing seems to have declined. Until 2017 the average was around 1,200 per year (2015 went up to at 1,627). 2018 = 832, 2019 = 634, 2020 = 732 and 2021 = 751.
Hebrew Character numbers seem to have halved since 2019, 2021 = 28.
Straw Underwing seems to be increasing, average 3 a year 20214-2017, 2018 = 13, 2019 = 6, 2020 =42, 2021 = 20.
Setaceous Hebrew Character seems to go up and down, lowest was 75 in 2014, 511 in 2018, and 508 in 2021.
Other observations
Tree-lichen beauty arrived in 2019, it’s now continued to appear since.
Box-tree moth arrived in 2017 and seems to be increasing.
Clifden Nonpareil also appeared in 2017 and has appeared in ones and twos since.
Dark Arches, Black Rustic, Broad-bordered Yellow Underwing, Common Quaker seem to be going down, but had increased previously so it looks as if it might be cyclic.
All of these were caught in a 40 w actinic heath trap. Location consistent and trapping all nights when the weather was ok. Garsington is a village just outside of Oxford and we are at nearly 400 feet. The garden is fairly unkempt with some native herbaceous plants but sadly few trees or bushes. There are trees in neighbouring gardens and close thickets. Some have been cleared for development. The village is largely surrounded by arable farmland.
Total species caught over the years is about 550(ish).
Hi Mark,
ReplyDeleteThat's interesting reading, thanks for putting it all together. Some moths do seem to have a noticeable cycle to their fortunes ("boom and bust" if you like) and Small Square-spot is one such species. My own garden records show its peaks and troughs quite clearly, with troughs around 2003/4, 2011/12 and 2019/20 and peaks in between during 2008 (649) and 2016 (864). In 2021 I had 47 individuals and the moth seems to be slowly working its way up towards another peak which I would expect in 2024. We'll see!