Scottish Borders Butterflies 2021

Due to Covid travel restrictions our planned holiday to Spain was cancelled for the second year in a row. I always look forward to a trip abroad and the opportunity to see different butterflies.  On previous trips to Spain I have managed to see about 40 species of butterflies, so for the second year in a row my tally was going to be particularly low.

I am lucky that we have some land where we have done much to encourage butterflies and just a few hundred metres above our house there is an amazing valley where there are a lot of interesting species. There are a few interesting species that occur a few miles away, so I decided this year to see how many species I could find in the Scottish Borders.

The year started off well with a couple of Small Tortoiseshells, Aglais urticae,  visiting the garden in March and in April Peacocks, Aglais io, and Commas, Polygonia c-album,  joined them. Despite the good start to the season the weather was cold and wet later in the spring and I didn't find any caterpillars of these species, which is unusual. However, they obviously did manage to breed as there were more adults later in the summer, but not in as good numbers as normal.

I am always pleased to see the first Orange Tip, Anthocharis cardamines, of the season, as to me they mark the start of the butterfly season. This year they did well here and were seen in good numbers.

Of the other three species of whites, the Green-veined White, Pieris napi, didn't do as well as normal for some reason. Unusually, it was outnumbered by the Small White, Pieris rapae. Large Whites, Pieris brassicae, are never really numerous, but they were a regular visitor.

In early  June I drove over to Burnmouth to look for Small Blues, Cupido mimimus. Although there was a cool breeze coming in off the sea I still saw quite a few, along with Small Heaths, Coenonympha pamphilus, Small Coppers, Lycaena phlaeas, and Wall Browns, Lasiommata megera.

Back home and a walk up the valley added Northern Brown Argus, Aricia artaxerxes, and Small Pearl-bordered Fritillary, Clossiana selene, to the count along with loads of Small Heaths, Ringlets, Aphantpopus hyperantus, and Meadow Browns, Maniola jurtina.

Red Admirals, Vanessa atalanta, arrived in June and in September their numbers picked up as the new generation appeared. I was amazed how long they remained here with the last one I saw being on the 25th October, long after the first frosts.

At the beginning of July I headed towards Treepwood where I had seen old records of Large Heaths, Coenonympha tullia. It was difficult to find a suitable location amongst the fields grazed by sheep, but eventually I managed to find a boggy area with Cotton Grass growing. After much stumbling about I was delighted to find one Large Heath. I am not sure if numbers would have been higher earlier or later in the year, but hopefully they are doing well there.

In another visit up the valley above the house that month there were a few Dark Green Fritillaries, Argynnis aglaja, and loads of Small Skippers, Thymelicus sylvestris. Amongst them I spotted one Large Skipper, Ochlodes sylvanus.

Towards the end of July I went to Kelso to look for White-letter Hairstreaks, Satyrium w-album. Iain Cowe, the Borders butterfly recorder, had previously shown me how to find eggs on Elm trees, so I headed to the same spot. Within a few minutes I spotted some butterflies high in the trees and a little later one kindly flew down and landed on a branch next to me.

I was planning on a visit to a valley a few miles away to see Scotch Argus, Erebia aethiops, but the weather at the weekends was disappointingly poor. However, one lunchtime when I was walking around my meadow, I spotted a dark butterfly which turned out to be a beautiful fresh Scotch Argus. Of course, I didn't have my camera with me and I couldn't find it once I had run back to the house to get it! However, six days later I spotted a quite faded Scotch Argus in the meadow. Unfortunately, I will never know if it was the same butterfly!

So, I managed to see 23 species of butterflies in the Scottish Borders this year. I don't think there are many more species that I could have seen. Green Hairstreak, if I had been in the right place, possibly Grayling somewhere on the coast and Painted Lady, had there been more around this year. I was very pleased to have seen a Large Heath and White-letter Hairstreak - two butterflies I have never seen before.

Plantation Dilemmas

Our woodland used to be part of a larger estate. Some old documents refer to it as the woodland garden, but later maps call it Sawmill Wood. It seems that it was originally set out as a formal woodland, visible from the big house. I have seen photographs from the middle of the 1900s and it all appears to be large deciduous trees, with one picture showing some haystacks, so obviously there was grass growing under them.

In the 1970s it seems that a lot of the larger trees were cut down and there were quite a few areas around the estate that were planted with Norway Spruce and Scots Pine as a Christmas tree crop. Sadly the owners of the estate died shortly afterwards and the land was split into several smaller lots and sold off.

We had three compartments of “Christmas trees” on our land, two of Pine and one Spruce, each about two acres. The trees were now about 50 years old and about 80 feet tall. It was interesting to see that the ground under the Spruce was completely bare, with no grass, wild flowers or young trees growing. Under the Pine there was at least some vegetation, but it was quite sparse.

Two years ago we decided to have the Spruce plantation clear-felled and the adjacent Pine plantation thinned. This turned out to be quite a messy operation, as typically it coincided with a period of sustained rain! The forestry vehicles sank into the ground, so they used the brash from the trees to make temporary tracks. The mud trailed down our drive to where the trees were stacked, ready for collection. Once the work was completed we were left with a scene of devastation, with enormous piles of brash and branches scattered all over the area.

I spent the following year trying to clear the ground sufficiently to allow me to re-plant the area. This presented me with quite a dilemma. The whole idea of taking the Spruce down was to replant the area with native broadleaf trees that would provide a much better habitat for wildlife. Now I found myself having enormous bonfires. It felt so wrong to be producing all of this carbon dioxide, particularly after I had arranged to have the CO₂-absorbing trees felled.

A little bit of research was required. I know that you can’t believe all that you read on the internet, but I discovered a study that had been undertaken in Scandinavia. The researchers measured the CO₂ levels in a conifer forest prior to and after felling. It seems that for the first 15 years after felling and replanting a woodland the microbes in the soil produce more CO₂ than the young trees absorb. For the next 15 years the trees absorb more CO₂ than the microbes produce, but it takes that time to balance out the previous 15 years. So, it is only after 30 years that the woodland becomes a net CO₂ sink.

I also read that if you leave wood to rot, rather than burning it, the greenhouse gases produce are about the same, but obviously they are released over a much longer period. All interesting stuff, and quite alarming!

I also decided that it was better to leave piles of branches to break down, which would at least provide shelter for all sorts of wildlife rather than burn everything. Clearly the wood would be eaten by various invertebrates and then the rest of the food chain. Surely this would be a form of carbon sequestration.

It was very interesting to see how quickly the ground became colonised by wild flowers (or weeds, depending on how you look at it!). That first summer there was a carpet of Woodland Groundsel, Senecio sylvaticus, and a number of Spear Thistles, Cirsium vulgare, providing loads of flowers. There were also loads of young Foxglove plants, Digitalis purpurea, so the whole area had greened up by the end of the summer. The picture below is the thinned Pine plantation.

The following winter I planted 700 native broadleaf trees. A third of these were Sessile Oak (a condition of the felling licence) and the remainder were made up of Birch, Rowan, Field Maple, Aspen, Hawthorn, Blackthorn, Hazel, Crabapple, Cherry Plumb, Hornbeam and Willow. I also put in some Walnut trees, which are not native, but I wanted an alternative large tree and thought these could do well if the weather becomes warmer.

Many of these trees will provide flowers and fruit for pollinators, birds and small mammals. The trees are planted at 3 metres apart, but I have left open areas where I will continue to encourage wild flowers. I will also make sure that the trees do not become so dense that they block the light to the greenery growing below them.

It was lovely seeing the number of bumblebees enjoying the Foxgloves this summer and it is very exciting seeing the trees starting to grow. Some of them have even reached the top of their protective tubes. Despite the hard frosts last winter I only lost six trees out of the 700 planted. This is a picture I took this winter.

I am really looking forward to watching this area develop over the next few years.

Peacock emergence

Most years I find several groups of Peacock and Small Tortoiseshell caterpillars on nettles, but strangely this year I haven't found any at all. I had feared that the late spring had meant that very few had been able to breed this year, but luckily in August the Buddleia bank was covered in Peacocks, Small Tortoiseshells and Red Admirals, so they must have laid eggs on a patch of nettles close by, unnoticed by me!

Last year there were several groups of Peacock caterpillars on the nettles in my meadow. I collected a couple of caterpillars in June and kept them in a mesh cage so that I could watch then develop.

On 4th July both caterpillars crawled up to the top of the cage and formed a J-shape and they formed into chrysalises on the 7th July.

On the 31st July one emerged at 11am. As always I missed this happening, having checked the chrysalis a little earlier in the morning. So I placed the twig that the other chrysalis was attached to on my desk, next to where I was working. At 4.45pm I heard a crack and noticed that the chrysalis had split open, so I grabbed my phone and managed to film the butterfly emerging.

Chrysalises tend to colour up a couple of days before the butterfly emerges, so it is reasonably easy to know which day the emergence will happen. I I used to imagine that they would emerge in the morning of a sunny day, but I have known butterflies appear in the early hours of the morning through to late afternoon and I have also had them emerge on dull, rainy days.

It was such a thrill to see this butterfly emerge. By the time its wings had dried out it was too late to release it that day. The following morning it was still on its twig, so I took it outside into the sun where it quickly took off.

Some Orange Tip Observations

Although I believe that it is best to leave nature to do its own thing and not to interfere, I sometimes I think it could do with a helping hand. The spring of 2020 was lovely, but the weather took an unfortunate turn for the worse in June.

In April and May of 2020 there were a lot of Orange Tips flying around and I found loads of eggs and caterpillars. Unfortunately, we had a lot of heavy rain in early June and most of the caterpillars I had been watching disappeared. After one particularly heavy shower I could only find one caterpillar, so I popped it on a Garlic Mustard plant that I had in a pot and put it in a mesh cage for safety.

On 27th June the caterpillar attached itself to the seed head with a girdle of thread and formed into a J-shape. It stayed like that for 3 days before shedding its skin and forming a chrysalis.

I kept the chrysalis in a mesh cage under an overhang of the house. It remained there all winter and eventually emerged into a butterfly on 11th May 2021. I was surprised as this was a dark cloudy morning and only 10 degrees. However, I had noticed its colour change over the previous week, so possibly it couldn't delay the process any longer.

As each Orange Tip's under wing pattern appears to be unique I was able to photograph any I saw and discovered that my Orange Tip was still living on 24th May. It had survived though a horrible period of weather with several periods of really heavy rain.

I often wonder if butterflies can survive heavy downpours or prolonged periods of rain and this one proved that they can. I have also wondered when I see an Orange Tip if it is the same one that I had seen the previous day, or if it is a new one that has flown into the area. Checking through the photographs I took this year, I have identified at least 28 different Orange Tips and only a few of them were seen on more than one occasion.

This spring I was pleased to see plenty of Orange Tips flying around. There were so many that quite a few Garlic Mustard seed heads had more than one egg on them. This is unusual, as it is thought that Orange Tip caterpillars are cannibalistic. I noticed two Cuckoo Flowers growing on the edge of our pond which were proving very attractive to female Orange Tips. When I checked one plant had seven eggs on it and the other had nine. These are really small plants and I find it hard to believe that there is enough to eat in one plant for just one caterpillar. 

A few days later I checked and the eggs had all hatched. I kept an eye on them and then suddenly on day 8 all the caterpillars were gone. I don't know if they were eaten or if they all decided to go and look for something more substantial to fee on. I think I will try to grow a Cuckoo flower in a pot next spring and see if I can attract an Orange Tip to lay an egg so I can see if the caterpillar stays on the plant.

How Butterflies Arrive in East Lothian

In previous posts I have described how Speckled Woods and Wall Browns have arrived in East Lothian over the last few years and then colonised the whole county.

They both worked their way up the east coast from Berwickshire, skirting around the Lammermuir Hills, which run along the south of East Lothian. This seems like an obvious route, taking advantage of the milder climate along the coast and avoiding higher slightly baron hills.

It does appear that the Lammermuir Hills, with a maximum elevation of only 535 metres, is quite a barrier for butterflies as they expand their range.

Speckled Woods were first recorded in East Lothian in 2009 right on the south east corner of East Lothian at Dunglass. A year later Wall Browns were discovered in the same location and both species spread around the coast and have also used river valleys as they have colonised the county.

When Large Skippers were also found at Dunglass in 2014 we all expected them to follow the same route, but we were disappointed not to find them further along the coast over the next few years. Instead, the odd record came in suggesting that they had followed the foothills of the Lammermuirs westwards. This summer they were found in good numbers at Levenhall Links, which is on the extreme west of East Lothian. So, it seems that they chose a completely different route across the county.

Of course, Large Skippers are not easy to spot as they whizz about between flowers and maybe they are under-recorded as a result.

It is interesting, then, that Small Skippers were first recorded in East Lothian between Aberlady and Gullane in 2011. They had been recorded previously in the Borders, but hadn’t been spotted anywhere in East Lothian. Over the years more records came in and we have watched them spread east and west along the coast. There were some early records from some woodland south of Aberlady and also up in the Lammermuir Hills at Linn Dean.

It would appear that these little guys took a completely different route into East Lothian and came over the Lammermuirs via Soutra. It is no coincidence that the two main roads coming north into East Lothian are the A1 which follows the coast and the A68 which comes up over Soutra. The highest point of the A68 at Soutra is 364 metres above sea level, so still a bit of a climb, but the lowest point away from the coast.

Last year we moved to the Yarrow Valley in the Scottish Borders. Our house is between 30 and 40 miles from the coast as the crow (or butterfly) flies, but this short distance makes a surprising difference to the weather. We are at 175 metres above sea level, which isn’t that much, but the elevation and distance from the sea appears to have quite an impact on the weather. I can’t say that it is very noticeable, but the season here is at least three weeks behind what it is in more coastal areas.

It is noticeable in the spring that the Daffodils are at least three weeks later, but even later in the year my Buddleia flower at least three weeks behind those plants in our East Lothian garden, from which I took them as cuttings.

Although the summers appear to be just as hot, if not hotter than on the coast it is interesting that the shorter season means that Speckled Woods and Wall Browns, that are now so common in East Lothian, haven’t made it this far inland. However, the more adventurous Small and Large Skippers have both arrived here. It will be interesting to see what the next few years bring.

Wall Brown, Lasiommata megera

Back in February 2018 I reported on how the Wall Brown had arrived in East Lothian and then continued westward across the county. I am pleased to say that the species has continued to do well and has now been recorded over most of the county.

The map below shows sightings up to 2020 and this year it they have been seen right along the coast to the west.

It is interesting how they have tended to move along the coast both in East Lothian and as they have spread up the country.

I moved about 40 miles south of East Lothian last year, but there are no Wall Browns here. They are very common along the coast, but haven't ventured inland. We certainly have a shorter season here and in the spring I notice that plant are up to three weeks behind those on the coast. Possibly the season is just too short for Wall Browns, but I do live in hope that we will see them here soon.