Dragonfly week, plus a local expert’s insight.

Female broad body chaser

Dragonfly week runs from 18th-26th July, lots of info can be found at https://british-dragonflies.org.uk/event/dragonfly-week-2020/

How about locally, can you expect to find many species on our reserves? First off head to where there is water; Logan’s Meadow, Barnwell East, Bramblefields, Paradise, Coldham’s Common, Stourbridge Common,Byron’s Pool, Sheep’s Green and Coe Fen are all excellant places to start. But then what?

A recent conversation with local expert Duncan Mackay revealed many great tips and advice on how to turn a passing interest into a life long passion.

The conversation went like this,

Why did you decide to survey dragonflies?

“I did it because it was an obvious area of the Natural History Cambridge survey that nobody else was looking at. I started out with a bit of knowledge about Dragonflies (I had done a course at the dragonfly centre at Wicken about 10 years earlier and had been photographing them since then).

I was at the start of my project far from being an expert, but I knew that if I tried to photograph everything, then I could study the photos later and get my identification much more accurate. So I adopted a system and whenever I arrived at a site I took a wide angle view of the site so I could work out where I was when I came back to the photos later. Then I started photographing the insects. I used a bridge camera which had a 60x zoom. This proved really important because if you can photograph the dragonflies from a distance you are much less likely to disturb them and can pretty much be certain of recording an image that you can verify the ID from.  I also made notes of what I found on my phone using the google keep app. So then when I went home I transferred the information from google keep onto a spreadsheet. I went through the photos and checked the ID I had recorded in the field with the field guides. The best field guide at the moment seems to be Britains dragonflies by Smallshire and Swash, although the Lewington field guide to dragonflies of Great Britain and Northern ireland is useful too.

Dragonfly

How do you initially choose a site to survey?

“Basically I was trying to cover as many aquatic sites within the Cambridge area. I scanned the OS maps for water bodies in the city.

I started with Hobsons conduit, but it quickly became clear that I needed a way to cover the whole of the Cambridge area, so I set up a number of cycle routes which I could do regularly and then started to record. I was really just trying to establish the distribution of the species but I started to count the numbers as well.

The species flying change each month, so I had to revisit the sites every 2 weeks or so.

How often do you go surveying and what times/months are best?

“I have been going out regularly 2 or 3 times a week (I am semi retired so can work my surveys in with my work) At first I was going out at lunch time and eating as I cycled. The best months are May to September but some species are out in April and also in October. So for young observers the summer school holidays are a great time to be out there.

Also 10am to 4pm are the best recording times and sunny days are important. As soon as the sun goes behind a cloud the dragonflies hide away. They love to bask in the sun to warm their bodies up. Damselflies are more tolerant of cloud cover, but are also more active in sunshine.

 

Damselfly

What species do you expect to see, what has surprised you?

 

“I started with no concept of how many species would be in the city. Almost nobody had looked in the city sites until recently. The collection of Dragonflies in the Zoology Museum were almost completely collected from places like Wicken Fen. Nobody it seems was interested in what we have in the city. So in the first month of recording I got to 10 species and was very pleased with that. Then I started to look at how many species other places had. I found Wicken Fen ( the mecca of Dragonfly hunting ) had 22 species. So I wondered how close I could get to that number. By the end of the first year I had got to 19 which seemed totally amazing. I was really pleased when I found not only red eyed damselflies, but also small red eyed damselflies. This is a species that 10 years ago was a very rare vagrant to the UK, but now was turning up on the science park lake. Then I looked back over all my red eyed photographs and found that I had misidentified them on several sites and they were more abundant than I could have imagined. By September of the first year I also found that there were not only Emerald damselflies but also Willow Emeralds. Again 10 years ago they were unheard of in the UK except as rare vagrants, but here they were in Cambridge….really exciting!  Then by the end of the first September the Willow emerald counts showed they were the most common damselfly in Cambridge in September. I was really excited by this. It seemed to me that this must surely be due to Climate change, evidence right here in the city.

 

In the second season (I could hardly wait for spring to arrive) I went hunting Hairy hawker dragonflies ( which had been missed in the first year as I started it in June). The first ones I found on Ditton meadows, then recorded them in a number of other sites. I also saw the first arrival of the large red Damselfly, the first to emerge in April. By the end of May I had reached 21 species, just 1 species less than the Wicken Fen total.

 

 

Dragonfly

The second summer also saw the discovery of Lesser Emperor in Barnwell lake and also the Southern Migrant Hawker on Ditton meadows. I also found the White legged Damselfly on Granchester Meadows. So by the end of 2019 I had got to 24 species, which for my reckoning was unbelievably good. We actually had 2 more species than Wicken and I had the photos to confirm all the ids. The Lesser emperor looked very like a faded female emperor and it was only when I studied the photos later that I realised what it really was. I sent the photos to Val Perrins the county recorder, who had never seen a Lesser emperor before, and he thought it was really a faded Emperor. It was only when I posted the photo on the Dragonflies face book page, that the chairman of the BDS rarities committee confirmed that I was correct in my identification.

Damselflies chasing

It does show that all the little nature reserves we have in Cambridge play an important part in conservation. Each reserve may not be as good as the big headline reserves, but when you add them all up together you get a diversity that is really significant. Of course dragonflies can get about by flying, so connectivity and corridors are not so important to them, but a range of diverse habitats in an area can play a significant role in providing niches for a diversity of species.”

 

 

Dragonflies mating

What species would you like to see turning up in the future?

“Well I think the Norfolk Hawker could appear, as it has been recorded from some sites quite close to Cambridge. I have photographed the Downy emerald in Shepreth, and it is possible that could be found in some of the more wooded Cambridge lakes. There are also records of Red Veined darters in this area from the past, so maybe we could find those here too. But the city was previously so under-recorded, that who knows what might be lurking. I would really like to find the White legged damselfly in more locations in the city. It likes flowing water and has been recorded from Hobsons conduit as a larvae about 10 years ago. So it may be present in low numbers.

 

 

Damselfly

Have you noticed any changes in species count due to weather conditions etc?

“The new species (Willow Emerald, Small Red eyed Damselfly, Lesser Emperor and Southern Migrant Hawker) are part of a wave of new species in the UK. There are quite a few species on the continent that are beginning to cross the north sea. So I await the next new arrival.”

 

 

Banded demoiselle damselfly

Any useful pointers or advice for the beginner?

“I think Photography, particularly using bridge cameras with big zooms(40x to 60x) are great for producing photos which you can then study at home and post on one of the forums to get confirmation of your identifications. Plus I like to use a small pair of close focusing binoculars to scan the reed beds. My current favourite binoculars are Nikon travelite ex 10x25s they are really compact and light so very comfortable to use with brilliant optics. Even my grandchildren use them at 7 and 5 years old, but they dont understand Grandads obsession with Dragonflies. When they are trying to get me to go somewhere with them, they always add “you have got to come because the dragonflies are going to be really good there”. We went fishing last week and I found a new location for Scarce chasers…so maybe they are right!”

Damselflies mating

Please go to Dragonfly and Damselfly Survey

to see the results of Duncan’s surveys.

Featured images by Duncan Mackay.

 

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