The earlier pictures were taken on my wee compact Canon ixus 970IS, which involved sneaking up on the butterflies. This can be very frustrating when they fly off, but very rewarding when they don't!

Since 2012 I have been using a Panasonic Lumix FZ150, which allows me to zoom in to the butterflies from a couple of metres away.



Monday, 26 March 2018

More Graphs!


In my previous post I compared last year's butterfly records with the average for the previous five years.

I then realised that back in 2001 I had a job as a seasonal countryside ranger at John Muir Country Park, here in East Lothian. I used to keep a record of the butterflies I saw each day and I also walked a transect. So, I thought that it would be interesting to compare my 2001 records with the last five years.


I know it is not very scientific to compare the results of one person from one site with those of several people from all of East Lothian, but nonetheless I have noticed some interesting results.

These first few graphs don't show anything too remarkable ...







... as I expected saw fewer butterflies than the current 20 or so recorders, although I was outside all day five days a week. However, what I notice is that my records from 2001 appear to be about two weeks later than the average over the last five years. John Muir Country Park is coastal and well known for its sunny weather, so if anything I would expect butterflies to appear there earlier than much of the rest of East Lothian.

Could this possibly be a sign of climate change?


The Green-veined White seems to be a remarkably consistent butterfly. Year on year its numbers don't appear to change much.


And I was interested to see how few Large Whites I saw. They certainly seem to be more common these last couple of years than I remember them being in the past.


The Red Admiral has certainly become more common over the last few years. It now appears to be able to survive the winter here, but in 2001 I didn't see any until the end of June.


And I had the impression that there are fewer Small Coppers around these days than there used to be. My records from 2001 appear to confirm this.


The Small Heath intrigued me when I worked at John Muir Country Park. They appeared to have a very much shorter season there than elsewhere in East Lothian where I was surprised to see them several weeks after they had finished at John Muir Country Park. Checking the more recent records, from 2010 Small Heaths appear to have a much longer season. It makes me wonder if they used to have one generation a year, but now can manage two.


The Small Tortoiseshell used to be a very common butterfly, which has declined quite seriously in numbers over the last few years. It is amazing to see how many more there were in 2001.


In contrast it appears that the Small White is more common these day than it was back then.



I also notice that back in 2001 I didn't record any Commas, Small Skippers, Speckled Woods or Wall Browns, as they hadn't arrived here then. In 2001 I didn't record any Painted Ladies, either, although I do remember seeing several in 2000. So, 2001 was obviously not a year when they arrived here in large numbers.


I was wondering if my mind was playing tricks on me, but my recollections appear to be backed up by the figures. What we can't be clear about is the cause of these changes. It is easy to jump on the climate change bandwagon, but it might just be the cause.


I promise, there will be no more posts containing graphs this year!!

Saturday, 3 March 2018

5-Year Comparisons


I have mentioned in my previous couple of posts how things have changed for Speckled Woods and Wall Browns over the last five years in East Lothian. These two species have both extended their range northwards and only arrived in the county within the last ten years.


I have been comparing 2017 figures with the previous four years for all of the species occurring here and it is apparent that some species have done very much better than others. I had my own perceptions of how well each species had done, but it is interesting to see the combined records from all of the volunteers.

The problem with doing a comparison like this is that each year I have had more people send in their records  to me, so you would expect to see more records for each species. However, this hasn't been the case with many of them.


For instance, when looking at the Large White, Small White and Green-veined White, there is a marked difference in how they did in 2017. These three species that share very similar life cycles, with a spring generation and a summer generation. It is odd that the Small White apparently had a poor second generation, but the other two species did as well as ever.

In the graphs below the red line shows the 2017 records. The blue line is the average figure for the last five years.




I had thought that there had been fewer than normal  Peacocks around in 2017, but when I looked at the records received they appeared to have done better than normal.



This is in contrast with the Small Tortoiseshell, which seemed to have a very poor year. I was surprised to see that there were more records than I expected.



2017 was an amazing year for Red Admirals. They have been increasing in numbers over the last few years and it is thought this is because they are now able to survive the winter in the UK. Whether this is because the temperatures are warmer than in previous years, or if they have adapted to our climate is unknown. It will be interesting to see how the very cold winter we are experiencing just now will impact on their numbers later this year.



What I find most interesting is that the species, such as the Wall Brown, Speckled Wood and Small Skipper, which have all moved into East Lothian in the last nine or ten years, have continued to increase in numbers, while some long-established species have been declining.


Most people who submit butterfly records to me it was felt that 2017 was a poor year for butterflies. As I mentioned previously we may be showing a falsely rosy picture of how the butterflies did, as we had more people sending in records. However, the differences between the species is valid. 

It will be interesting to see what happens in the years to come.


Friday, 9 February 2018

The Fall and Rise of the Wall Brown

While I was delighted to see the arrival of the Wall Brown, Lasiommata megera, in 2010 and its subsequent spread across East Lothian I note that it has declined severely in Southern England. Strangely, it is hanging on around the coast of England, but since the mid-1980s, what was once a very common butterfly has become a rare sight in an area centred around Buckinghamshire and Oxfordshire.

The Wall Brown normally produces two generations of butterflies a year. The first generation emerges in May and June and a second generation occurs in August and September. This species over-winters as a caterpillar.

A study, published in December 2014, The lost generation hypothesis: could climate change drive ectotherms into a developmental trap? By Hans Van Dyck, Dries Bonte, Rik Puls, Karl Gotthard and Dirk Maes looked at the declining number of Wall Browns in Belgium.

Their theory is that due to climate change the season for this butterfly is extending. If the first generation is emerging earlier and the subsequent generation is therefore appearing earlier then there is a potential for a third generation to emerge late in the season. However, there is not enough time for this third generation to breed, or for their eggs to hatch in time to make it through the winter. Presumably, eggs and chrysalises can’t survive frosts. It would be interesting to know if all instars of the caterpillar can survive cold weather.

This theory sounds very plausible to me and it could also help to explain why the Wall Brown is now spreading north into East Lothian. We have certainly been experiencing less severe winter weather here over the last 20 years. Possibly before that our season wasn’t long enough for two complete generations to survive and go on to produce caterpillars before the winter set in. In effect we are now experiencing the sort of weather that was once more common in the Home Counties.

Number of Wall Brown records received over the last five years
2013
2014
2015
2016
2017
54
78
70
129
273

2017 was the best year we have had for Wall Browns. The number of records I have received has increased each year since they were first recorded in East Lothian in 2010. Last year we recorded more than twice as many Wall Browns as we had in 2016. They have now made their way right around the coast and to various inland sites.

They are a very welcome addition to the butterflies of East Lothian.

Sunday, 4 February 2018

Speckled Wood - Pararge aegeria - 2017

In a previous post I explained how the Speckled Wood, Pararge aegeria, had arrived in East Lothian in 2009 and then colonized much of the county over the next five years. Well, I am pleased to say that they are continuing to do well. In fact in 2017 they were the secondly most commonly recorded butterfly here.



I have been looking back at the butterfly records for all species recorded here over the last five years and then comparing the 2017 figures with the average figures for that period. In the graph below the average number of Speckled Woods recorded over the last five years is shown in blue, with the 2017 records shown in red.



You will see that Speckled Woods did exceptionally well in the spring, but the poor weather in June and July impacted on their numbers. However, they made a bit of a resurgence later in the year.

Speckled Woods are interesting in that they can spend the winter as either a caterpillar or chrysalis. Those that we see here in April and May are thought to have spent the winter as a chrysalis. The larger peak in population from mid-June to mid-July are those that spent the winter as a caterpillar. There is usually then a much bigger second generation later in September. 

Looking further back, the number of Speckled Woods recorded in East Lothian has shown a steady increase since they were first recorded in 2009. 2014 was a very good year for many species, and Speckled Woods did particularly well then, but even with the poor start to the summer we had in 2017 they did better than ever.



Year
No of
Speckled Woods


2009
2
2010
1
2011
16
2012
11
2013
134
2014
1019
2015
465
2016
692
2017
1174

I have been mapping where Speckled Woods have been recorded and the previous maps are shown on my earlier post. This year the Speckled Wood has continued to spread and it can now be assumed it occurs anywhere there is suitable habitat in East Lothian.



It is interesting that in a year when many species of butterflies have done so badly, this species has done well. The new arrivals in East Lothian appear to be getting on better than many of the species that have occurred here for many years.



Sunday, 21 January 2018

East Lothian Butterflies 2017 - Part 2

Following on from my previous post here are the remaining species recorded in East Lothian in 2017.

Green Hairstreak, Callophrys rubi
The Green Hairstreak is probably very much under-recorded in East Lothian. There are old records from the Lammermuir Hills, but they have not been seen in those sites for many years. They have, however, been discovered in other areas of the Lammermuirs and in woodlands on the East Lothian side. They require blaeberries as food plants for the caterpillars, and everywhere we have found them is within a few feet of conifer trees. Numbers appeared to be down in 2016, but it is difficult to tell how they are doing without more specific monitoring.


Painted Lady, Vanessa cardui
Painted Lady numbers are very variable year on year, depending on many factors on their long migration from Africa to the UK. We don't ever see enormous numbers of them in East Lothian. The first record for East Lothian was on 5th May and it looks as though there was a better than average arrival of Painted Ladies. They didn't go on to produce a large second brood, presumably as a result of the summer weather.


Small Heath, Coenonympha pamphilus
The Small Heath confuses me a little! In the south of the UK there are two generations a year and up here we are supposed to get just one generation. However, I have noticed a big difference between sites in East Lothian. They are rarely seen beyond the end of June in John Muir Country Park, yet in other sites are seen through until the end of August. In 2017 the first record was on 6th May. They started off doing well, but their numbers were lower later in the season. We have been getting later records each year, but in 2017 we had a remarkably late record of one being seen on 20th October. I can only imagine this was from a second brood.


Common Blue, Polyommatus icarus
The Common Blue was seen in slightly lower numbers than normal in 2017, with sightings being lower than average towards the end of the season. The first Common Blue was recorded on 31st May and they had a fairly normal year with numbers just a bit down on the average.


Small Pearl Bordered Fritillary, Clossiana selene
The Small Pearl Bordered Fritillary is a very rare butterfly in East Lothian, only being recorded in a couple of places in the Lammermuir Hills and at John Muir Country Park. This year I only received one record on 7th June from John Muir Country Park.


Ringlet, Aphantpopus hyperantus
Ringlets did reasonably well in 2017. The first record received was on 14th June and their numbers built up quickly to a maximum, three weeks later and then back down to zero in the next five weeks.


Northern Brown Argus, Aricia artaxerxes
The Northern Brown Argus only occurs in a few small colonies in East Lothian. There is one very well established colony in the Lammermuirs, a very small and precarious colony on a golf course near Dunbar and possibly another couple of inaccessible sites where they occur. They tend not to travel far from their food plant, Rockrose, and therefore don't have much likelihood of spreading in East Lothian. The first record in 2017 was on 17th June and because we receive so few records it is difficult to assess how well they are doing.


Large Skipper, Thymelicus sylvestris
It was very pleasing to receive two records of Large Skippers in 2017. In 2014 we received our first record on the coast just inside East Lothian. We had expected them to continue along the coast, as many other species have, but despite many people searching there were no sightings in 2015 or 2016. Then on 17th June 2017 someone spotted them in two locations in the foothills of the Lammermuir Hills. They had caught us all off guard and sneaked west! I am sure there will be plenty of us out checking appropriate sites along the Lammermuirs in 2018!


Meadow Brown, Maniola jurtina
The Meadow Brown is normally the most numerous butterfly in East Lothian, but this year it was knocked back into four place. The first record we received was on 19th of June and this coincided with the start of the horrible rainy weather. It is interesting to see that numbers picked up to almost normal levels in August once the rain had stopped!


Small Skipper, Thymelicus sylvestris
The Small Skipper was first recorded in East Lothian in 2011 and since then it has been increasing in number and spreading across the county. This butterfly was first spotted at Aberlady bay, then in Saltoun Wood, other sites along the coast, Gifford, Linn Dean and Haddington to mention just a few. It would be interesting to know it manages to get to all these sites. Does it fly large distances, or is it that we just haven't noticed it in places between these sites?


Grayling, Hypparchia semele
The Grayling is only regularly seen in two or three sites in East Lothian. Unfortunately, one of those sites, Blindwells, is due to be developed and public access is being restricted. They are normally seen between mid-June to the end of August. The first record I received in 2017 was on 24th June and numbers seemed low this year.


Dark Green Fritillary, Argynnis aglaja
The first record in 2017 of a Dark Green Fritillary was on 1st July. Sadly, because their emergence was during the rainy weather 2017 was their worst year of the last five years. Numbers of ad hoc and transect records were both less than half what would normally be expected.


Sadly, 2017 was the first year that I haven't received a record for a Holly Blue since 2009. There was a colony around the Newhailes and Brunstane area, which sadly seems to have died out and each year I have received one or two records from around the Gullane/North Berwick area. I live in hope that there is a little colony hidden away somewhere in that area.


I am very grateful to all of those who have contributed butterfly records. It shouldn't be too long before we are seeing butterflies again in 2018!

Wednesday, 17 January 2018

East Lothian Butterflies 2017 - Part 1

2017 was a strange year for butterflies. It started off reasonably well, but the summer butterflies were rather disappointing. Luckily there was a late autumn resurgence of Speckled Woods and Red Admirals, which boosted the overall number of butterflies seen.
We had a good spring in 2017 after a mild winter with only one dusting of snow. From the end of March until mid-June we had decent weather, but then we had a period of very heavy rain. This seemed to impact on many species of butterflies (and I am told some species of birds). Certainly I saw a batch of Small Tortoiseshell caterpillars wiped out by the rain in June and also an enormous group of Peacock caterpillars perished after three days of continuous rain in July.
This year, we had more people than ever sending in records. This has given a bit of a false impression of the number of butterflies that there were around. One thing I noticed this year was that there were very few records of large numbers of butterflies being seen.
I have looked back over the last five years' worth of records and noticed a worrying trend in that the number of butterflies per sighting has been steadily reducing each year.
Below is a summary of how each species did in 2017.

Peacock, Aglais io
A really early sighting this year, the first Peacock record I received was on 16th January on an unusually warm and sunny day. They were recorded every month through to November, with numbers peaking towards the end of August. Peacocks did reasonably well this year, unlike the Small Tortoiseshell, which has a very similar life cycle.

Small Tortoiseshell, Aglais urticae
The first Small Tortoiseshell was spotted on 25th January. They had a very poor year this year and despite the record number of butterfly records sent in, we had our lowest number of Small Tortoiseshells recorded for five years. What I found interesting is that the first Small Tortoiseshell recorded hibernating was on 17 August, only a couple of weeks after it must have emerged. More hardy Small Tortoiseshells were seen flying until 14th September.

Red Admiral, Vanessa atalanta
The first Red Admiral recorded was on 9th March. I would speculate that this was an individual that had spent the winter here. They were seen every month after that right through to December, with numbers peaking in September. This was our most commonly recorded butterfly this year, and it did very well all over the UK. This is a butterfly that only a few years ago was considered as a migrant, but which has now firmly established itself here.

Comma, Polygonia c-album
The first record of a Comma this year was on 12th March. The Comma has never been a particularly common butterfly in East Lothian. Since first being recorded here in 2001 their numbers have picked up each year, peaking in 2015. For some reason 2016 was a terrible year for them and in 2017 there have been a few more seen, but still worryingly low numbers.

Green-veined White, Pieris napi
The first Green-veined White was recorded this year on 1st April. They seemed to have a fairly average year, but I think in reality numbers were lower than usual (given that we had more people recording butterflies). Certainly, the number recorded on the transects was lower than average.

Orange Tip, Anthocharis cardamines
The Orange Tip was first recorded on 6th April. The number recorded was a little higher than average, as expected. The adult stage of this butterfly usually flies between April and mid June, so they missed the terrible weather just after that.

Speckled Wood, Pararge aegeria
The first Speckled Wood was seen on 8th April. There are generally three peaks in population of adult Speckled Woods throughout the year. Possibly the first to appear had spent the winter as a chrysalis. The second peak, in June, could be those that spent the winter as caterpillars. This year the number of records received in June was much greater than in previous years, but the later generation was not so spectacular, although there were a great number of records received in late September, making this the second most numerous butterfly recorded in East Lothian in 2017.

Small White, Pieris rapae
The Small White was also first recorded on 8th April. I think that the Small White is generally a little unrecorded, as it is difficult to identify unless it lands. 2017 started off reasonably well for the Small White with normal numbers being seen in the spring. However, the summer generation was very reduced, presumably as a result of the heavy rain during June and July.

Large White, Pieris brassicae
The Large White would normally follow a similar pattern to the Small White. The first record for 2017 was on 8th April and thereafter the Large White had a fairly average year. More were recorded this year than the previous three years, but remember there were more people recording them. Why the Small White struggled and the Large White didn't appear to be affected by the weather is a mystery to me!

Wall Brown, Lasiommata megera
The Wall Brown was one of 2017's success stories. First recorded here in 2010 the Wall Brown has since been spreading westwards around the coast and to several inland sites. In 2017 the first record was on 20th April and the first generation continued to be seen until  3rd June. The second generation started on 5th August and it was recorded through to the 19th September in much greater numbers than in previous years.

Small Copper, Lycaena phlaeas
The Small Copper has been fairly consistent in East Lothian over the last five years. 2017 wasn't very different from the average. 
I will continue with the remaining 12 species in my next post.