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.



Friday, 31 October 2014

Butterfly Transect

I find co-ordinating the local butterfly records really interesting. I hear first-hand about rare species that have been spotted and occasionally about something new. However, because more people are sending in records each year, I wonder if I am getting a false impression about how well the butterflies are doing here.
The UK Butterfly Monitoring Scheme operates a system of butterfly transects, which give a much better picture of how the local butterflies are doing. Each week between April and September I walk a set route near where I work and I count the number of butterflies I see within an area five metres in front of me and two and a half metres to either side.
I started my transect four years ago after noticing how many butterflies there were in a meadow where I often walk during my lunch break. I was a little disappointed when half way through the year the weather took a turn for the worse and the number of butterflies reduced accordingly. The following year it was even worse!
Last week I plotted the results of the last four years transects onto graphs and I noticed an interesting correlation between the number of butterflies and the weather at the time.
On the graphs below, week 1 is the first week in April and week 26 is the last week in September. Normally butterflies will start flying in April and peak about in the middle of May, there is a quiet period in June and then the summer species come out peaking again about the end of July.
In 2011 we had a great spring, but a horrible cold, wet summer. You can see that the butterfly numbers picked up well, but then dropped off when the bad weather hit. I counted a total of 506 butterflies that year.

2012 was the worst year I can remember. It seemed to rain almost every day! I was surprised to see any butterflies on the few occasions when the sun came out. However, you can see that the number of butterflies was considerably down on normal. I only 361 butterflies on my transect that year.

In contrast 2013 was one of the best years I can remember. It is interesting to see that the spring populations were low as a result of the bad weather their parents had experienced in 2012. I still managed to count 523 butterflies on my transect, though.

This year the weather was great again, although it did cool down quite a bit in August and September. The graph above shows what I would consider to be close to a normal number of butterflies. I counted a total of 1175 butterflies on my transect this year. So this really confirms that 2014 has been a fantastic year for butterflies here.



4 comments:

  1. That's so interesting. I'm glad it was a good year this year. Any predictions for next year, based on this?

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    1. Hi Sylvia. Well, I fear that some butterflies may not do so well next spring because August and September were quite cool here. The caterpillars that hatched onto the nasturtiums in our garden all perished in the cold. However, much will depend on what the weather does. If it is good then I think that we will see some of our newer species continuing to spread across the county.

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  2. That's great you are keeping records and projections of your findings. If everyone did this, it would surely help with environmental tendencies. If there are bird watchers, so can there be butterfly watchers also! I started a new blog so this is why you see a different avatar. The address is http://toysfrommychildhood.com
    I don't know whether it will interest you or not.

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    1. It is easy when you are interested in something to keep a note of what you have seen. Having kept records for a few years now it becomes more interesting seeing changes in populations and distributions. I have been encouraging others to keep records and I then share them around us all at the end of the year. It can only be good when more people take an interest in the natural world. I will check out your new blog - I thought you had been quiet for a while!!

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