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.



Wednesday, 6 January 2016

Butterflies through time (3)

In my previous two posts I talked about eight of the species of butterflies that have recently been recorded in East Lothian. I would call these new species, but as I have discovered many of these species occurred here many years earlier.

The three species below have been recorded in the last couple of years.

Small Pearl-bordered Fritillary, Bolora selene
There is a record in "The Butterflies of Scotland" of Small Pearl-bordered Fritillary from East Lothian in 1845, but by 1900 it was not recorded from East Lothian any longer. There are various scattered records from around Scotland, and it seems that it occurs in small isolated colonies. It was discovered again in East Lothian in 2013 in a small valley in the Lammermuir Hills.

Green Hairstreak, Callophrys rubi
There are scattered records from all over Scotland in "The Butterflies of Scotland", but it doesn't show any Green Hairstreaks occurring in the Lothians. The "Provisional Atlas of the Insects of the British Isles" confirms that the only records were further west and north of here. However, I have been told of two sites in East Lothian where they are said to have been found about 30 years ago. I have checked both of those sites with no success, but last year Green Hairstreaks were found in the Lammermuir Hills, just inside East Lothian. This year another colony was found a few miles further into East Lothian.

Large Skipper, Ochlodes sylvanus
"The Butterflies of Scotland" shows records for the Large Skipper occurring in south west Scotland in the early 20th Century. There are a couple of records of it occurring in the Scottish Borders in the late 19th Century, but there is some dubiety about these records. The 1970 "Provisional Atlas of the Insects of the British Isles" shows no records in Scotland. In 2014, having spread further north in the Scottish Borders a couple were found just inside East Lothian, on the coast.

So, there are 24 species of butterflies occurring in East Lothian. The eleven species mentioned in these last three posts were not recorded here in 1970 and have all apparently appeared here since then. However, as I have now found out, seven of those species did once occur here, as early as the 1800s, but they apparently died out after that.

This of course leaves the big question, why? I certainly can't imagine that the habitat has improved in that time. In fact, the amount of undisturbed space has diminished in that time. I did wonder if it was something to do with the industrial revolution or the use of pesticides, but that wouldn't have made the butterflies head south to more populated areas of the country. Then my wife's cousin cracked it. "What about the Little Ice Age?" she asked. This was something that I hadn't hear of previously.

She sent me some information about the Little Ice Age, and although it isn't unanimously agreed when it began or ended I found some interesting information on Wikipedia. Apparently the NASA Earth Observatory has detected three cold periods starting in 1650, 1770 and 1850. The period of cooling starting around 1850 matches very well with the disappearance of some of these species of butterflies.

That same Wikipedia page also shows a graph of estimated average temperatures, which shows a considerable increase in the last 20 years. This could be a possible reason for the other species extending their range northwards into East Lothian.

I think there are more people recording butterflies these days, but I don't think that is the reason these butterflies have been recorded. Many of the people who send in records have noted new species where they have not seen them before. Possibly some species such as Green Hairstreak and Graylings, which are quite difficult to spot, have been here, undetected for many years.

Of course these are just some initial thoughts and I recognise that there could be some flaws in my theories. I would be very interested to hear other people's opinions about this.

References:
Thomson, G (1980). The Butterflies of Scotland. London: Croon Helm Ltd.
Heath, J (1979). Provisional Atlas of the Insects of the British Isles. Biological Records Centre.

16 comments:

  1. Nick, my hats off to you. I like butterflies and delight in taking photographs of them. However, I don't have the perseverance and tenacity to do map out their habitats, much less do research into their past habitats. you are so driven in your pursuit.

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    1. Elsie, The more I learn about something the more I want to know. I find it fascinating to try to learn why these butterflies are changing their range. I have been like this all of my life. When I was little I used to take everything to bits to see how it worked!

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    2. Are you doing this as a hobby or it is part of your job. Sorry, if I sound too curious because the depth and breadth of your involvement borders on full time, lifelong commitment. Even your vacations are filled with such activities.

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    3. Elsie, it is a hobby that has become a bit of an obsession! I work with the Countryside Ranger Service, so they give me all of their butterfly records and we have a number of volunteers who also send in records of the butterflies they have seen. I look after public access, rights of way and paths for the local authority, so I do all of the butterfly stuff in my spare time. The more I find out about the butterflies there more I want to know. There are so many interesting aspects to their life cycles, habits and most recently the exciting period we are in regarding their range.

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    4. Wow! such devotion is most admirable. I've to admit that all I did with regards to butterfly is to point my lens at them and release the shutter. The world needs people such as you to record all these details for posterity.

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    5. One of the great things about modern phones and digital cameras is that there are a lot more records now of wildlife. This all helps to build up a picture of what is out there and hopefully we can take action to try to conserve them.

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  2. The first two are lovely, and the color of that 2nd one so unique, at least to me. About skippers, ours are purely brownish with a bit orangy hue, same shape as yours. Happy New Year!

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    1. Thank you Andrea. Happy new year to you, too.

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  3. Hello Nick!:)Thank you for your visit, nice to see you.It's intiguing about the demise of certain butterflies in areas where they have previously been seen and recorded, and the appearance of new species further north in East Lothian. Like you,I feel it has more to do with climate change, so your theory about the cold period of the 1850 seems perfectly logical for the disapearance of certain species, as do your other theories about the increase in numbers.Wish I could help with more information.Your answer to Elsie made me smile because my husband still does take things to peices to discover how things work.
    All the best.

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    1. Hi Sonjia. Yes, there is still so much to learn, but I find it fascinating. It would be interesting to find out how butterflies are doing further south. Of course the English Chanel is a bit of a barrier to movement.

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  4. Great shots and an interesting narrative.

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  5. so lovely to see your butterflies at a time of year where we have none. well i have read some are hibernating under tree bark and will come out on the first warm spring day. amazing to consider. i have never seen that lovely green one.

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    1. Hi Tammie Lee. We have no butterflies flying here, but I have found two species hibernating in old castles this winter and a chrysalis of another species in a hedge! They are all out there somewhere, but hiding away!

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  6. I’m glad the Small Pearl-bordered Fritillary didn’t disappear, it’s really interesting.

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    1. Hi Maria, It must be one of our rarest butterflies, but it is lovely. It would be lovely to see them extending their range here.

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