I have been collating the butterfly records from East Lothian for the last 11 years, so we now have good data to see how butterflies have been doing over this period. Of course we only record a very small fraction of the number of butterflies that occur in East Lothian, but it gives a pretty good picture.
2023 started off with a reasonably mild, but wet winter. However, there were a few colder spells and the frosts persisted into April. The year was punctuated with an unusually high number of easterly winds. There wasn't really a lot of sunshine until mid May, when we had a warm, sunny spell, but sadly that only lasted until half way through June! The remainder of the year was rather showery, with continuing east winds. This was only broken by a sunny week in early September and then back to cloud and rain! The first frost around the 12th October saw a sudden drop in the number of butterflies.
The weather can have an impact on the number of butterfly records received. This isn't necessarily because the butterflies aren't out and about when the weather is poor, but may be because recorders are less likely to be out looking for them. It is often the weather from the previous year that can have more of an impact, preventing the adults laying eggs, or heavy rain washing small caterpillars off their food plants.
Some species had a really poor year in 2023, but others did surprisingly well.
The first record I received was of 3 Peacocks seen on the 17th March and several more were seen over the next few days. They had a pretty good year, particularly later in the summer when the new generation appeared.
On 23rd March I received the first record of a Small Tortoiseshell. Nationally there is much concern about the reducing number of Small Tortoiseshells, yet here their numbers have been fluctuating, but not really showing a decline. The number of records in 2023 was just a little lower than the average of the previous ten years.
The third species that overwinters as an adult is the Comma and they had a particularly good year, being seen in high numbers later in the season. The first one was spotted on the 2nd April. It is interesting that these three species have similar life cycles, feeding on nettles as caterpillars and hibernating as adults, yet they each had different success rates in 2023.
The next butterfly to be seen was a Holly Blue on the 3rd April. This was the real success story of 2023, with them being spotted all over the county in good numbers. It seems funny to think that prior to 2019 they were rarely recorded in East Lothian. I received records of 377 Holly Blues last year.
Next were the whites with Small White, Large White and Orange Tips first being seen on the 3rd, 5th and 7th April. These three species all had a good year with higher than average numbers being recorded. However, the Green-veined White didn't make an appearance until the 19th April and it had the worst year since I have been collating the butterfly records. It is difficult to understand why it did so poorly when the other white species did so well. My only suggestion is that I usually associate Green-veined Whites with river banks and damper areas. Possibly the dry springs that we have had the last two years haven't suited it. Hopefully the numbers may bounce back in the future.
The first Speckled Wood appeared on 7th April. They had a fantastic year in 2023 and were seen in particularly high numbers in early September. It is interesting to speculate why they did so well in a year when the weather wasn't what we wouldn't normally think of as ideal for butterflies.
The Wall Brown has slowly been increasing in numbers over the last ten or twelve years in East Lothian. However, the number of records peaked in 2021 and since they have decreased again. Nationally there is concern about this species reducing in range and numbers and it had been thought that Wall Browns were spreading north in response to climate change. This year, we received the first record on 25th April with the summer generation being much more numerous than the spring generation.
Small Coppers are never really seen in big numbers. More often than not a male will take up territory on a sunny leaf and fly up when disturbed only to return to the same spot. The first record in 2023 was on 26th April and it wasn't a particularly good year for them, which I can only imagine was down to the weather.
Although Red Admirals appear to be able to survive our winters as eggs, caterpillars, chrysalises or adults, the vast majority of those we see in the early summer have flown up here from continental Europe. However, there are a few early records, which are likely individuals that have found somewhere sheltered to over-winter. Our first record last year was on the 4th May, so it is difficult to be sure where this individual spent the winter! 2023 proved to be a bumper year for Red Admirals with 1421 individuals being recorded. The highest figure since I started collating the records. There were an enormous number of records in the third week of June, pointing to a mass arrival from overseas.
No comments:
Post a Comment