There has been a lot in the national press about how badly butterflies have done in 2024. Certainly the weather wasn't ideal for them, but looking through the records I have received, I am surprised that things in East Lothian weren't as bad as I was expecting. Some species did well while others were seen in very low numbers. It is difficult to know why this should be.
The year started off with quite a mild, but stormy winter. Much of the spring and summer was cooler, with a lot more cloud and showers than normal. Of course, there were a few sunny days, but the weather really didn't improve until September, which was a little late for the butterflies!!
There is no perfect way of recording butterflies. Transects are great for comparing year on year for the same location, but in East Lothian they are mostly coastal, with two along the River Tyne. The ad hoc records are from all over the county and can pick up all sorts of interesting records. However, there is a lot of luck involved with being in the right place at the right time. They can also result in big spikes because a lot of enthusiasts, including myself, may be out on the same sunny day looking for butterflies!
Poor weather not only means that butterflies may not be flying, but also enthusiasts may not be out looking for them! However, it is amazing how quickly butterflies will appear when the sun does come out but they may go unnoticed if recorders aren’t out and about!
The records I have gathered are from ten transects that are currently walked in East Lothian along with ad hoc records from the East Lothian Countryside Rangers and about 20 volunteers. This gives a pretty good indication of butterfly numbers and can be compared with the previous 11 years when about the same number of people have been submitting records.
The first butterfly record I received from East Lothian was a Peacock on 16th February. This was quite early, possibly reflecting the mild winter. Peacocks did quite well in East Lothian with high numbers been seen later in the year.
In contrast the Small Tortoiseshell had a very poor year. Their numbers have been declining in recent years, with 2024 returning half the average number in East Lothian and it was the worst year for them since I started these comparisons in 2013. This is a worrying trend that has been seen across the UK.
The Red Admiral also had a very poor year. We had a few early records, which may have been butterflies that had survived the winter here. The arrival of migrants was a couple of weeks later than normal and then we had lower numbers later in the year when normally we would expect to see the next generation.
The figures for Commas in 2024 would suggest it was a fairly average year for them. However, a good proportion of the records were from three counts of over 20 Commas that were recorded in one particular woodland in September.
2024 was the worst year since I started collating the records for Painted Ladies. I only received 14 records of them and I haven't seen one in the UK for the last two years. The numbers that make it to our shores depend on how their relatives have done earlier in the year on their multi-generational journey from Northern Africa. In good years, such as 2019 their numbers can be spectacular.
Orange Tips had a very good year. They appeared a little later than normal, but were seen in good numbers.
Interestingly the spring population of the Green-veined White and Large White were lower than normal, but their numbers picked up for the summer generation. So, both species ended up being recorded in fairly normal numbers.
Small White numbers can vary enormously from year to year. 2024 numbers ended up being just a little less than average.
One of our more recent arrivals (2009), the Speckled Wood, had a fairly normal year.
The Wall Brown, which arrived about the same time, peaked in numbers in 2021, but has since been declining. 2024 saw about a quarter of the number recorded in 2021. There has been a dramatic reduction in numbers of this species in England and although it appeared to be moving north in response to climate change it will be interesting to see what happens to the East Lothian population in the coming years.
The Small Copper had a very poor year, with the lowest number since I started collating butterfly records. 2024 saw about a third of the average number.
Two species that appeared to have a very good year were Common Blues and Dark Green Fritillaries. They both tend to live in similar habitats and fly in June till August.
However, another species that inhabits similar landscapes is the Small Heath. Sadly they had a poor year, which is a little difficult to understand.
I will continue this on the next post.
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