BBC Radio Northampton, the Big Butterfly Count and Brimstones in the Garden!
I’m sure it will come as no surprise to anyone when I share the news that so far 2024 has been one of the worse seasons we have had for a very long time. The continuing westerly winds have brought in seemingly endless bands of clouds and rain across Northamptonshire. These weather fronts have affected both the spring and the summer populations of butterflies. Below is a graph I have made up to show a snapshot of the current situation. It shows the total adult butterflies recorded in 2023 and 2024 up to the 12th of July for a selection of butterfly species. As you can see, with the exception of the White Admiral, all the other species are markedly down from last year. Please note that I don’t have all the transect data yet so some of the 2024 totals may go up slightly when I receive them, however, it does paint a rather gloomy picture!
As you can see in the chart, the Small Tortoiseshell after having a terrible season in 2023 seems to be having an even worse one this year. The summer emergence for the species has just started so let’s hope that numbers can bounce back somewhat otherwise there will be serious concerns for the species. I was very pleased when I was surveying some private land up in the north of the county at the start of the week to find two freshly emerged Small Tortoiseshells.
Fortunately, Butterfly Conservation’s Big Butterfly Count started on the 12th of July. This is an amazing citizen science project which encourages the public to give up just 15 minutes of their time to record the butterflies they are seeing. The beauty of the Big Butterfly Count is we very often get data for areas we wouldn’t get them from as people record in their gardens, on walks or even in towns when shopping etc. If you would like to take part please check out the Big Butterfly Count website - www.bigbutterflycount.butterfly-conservation.org, you can download a handy mobile phone app to make is easier to record in the field, or you can also add your records to the website when you get home if that’s easier. There are also a couple of Big Butterfly Count events coming up, Jamie Wildman is leading one in Salcey Forest and you can find the details for that here, and I will be helping out at a similar event at Earls Barton church on the 27th of July and you can find details of that here. Coincidentally, also on the 12th of July I was invited onto BBC Radio Northampton’s Bernie Keith show to talk about the current situation of the butterflies in the county, it was great fun and it was great to finally meet Bernie after listening to his shows for so many years. If you would like to listen to the interview you can by clicking here on BBC Sounds, if you just want to hear my piece skip to around the 46 minute mark.
On a lighter note the Brimstones have certainly been very busy in our garden this year and our largest Buckthorn has seen quite a lot of larvae busily feeding on the leaves. The life cycle started on the 15th of May when I inspected the bush after a day out and found it to be covered with Brimstone eggs.
The young larvae hatched from the eggs and could be seen feeding on lots of leaves, they seemed to be particularly fond of the shadier parts of the bush. In a previous year, we did have an issue with ants attacking the larvae but fortunately, they didn’t seem to be a problem this year and after a few weeks the larvae were full sized and were chomping their way through quite a few leaves. This photo was taken on the 17th of June.
At this point the larvae became rather active and after finishing a leaf they would set off along the branches to find another spray of leaves somewhere else on the bush. Brimstone larvae have a curious defence strategy when they attach themselves to the leaves using their rear end and raise the rest of their body into the air. It is remarkably good camouflage as if you take your eye off one it can take a while to find it again.
Then, towards the end of June, all of the larvae suddenly disappeared. I had hoped that I would find a Brimstone pupa this year but I didn’t realise the bonanza of Brimstone pupae I was about to find. It all started on the 28th of June, which for us here in Wootton is bin day. When I brought the bin back in after being emptied I was amazed to find a Brimstone pupa on the handle! This lucky butterfly had somehow survived me walking the bin to the front of the house, the bin men handling it and raising it vertically into the air to crash against the side of the bin lorry. With the exception of breaking its silk girdle, it somehow came out of this ordeal unscathed.
After finding this one I then inspected the Buckthorn bush. According to the books, Brimstones only rarely pupate on the foodplant as they prefer to travel quite long distances before pupating. The one on the wheelie bin must have wandered at least three meters before deciding the bin handle was the best option. So I was quite surprised when I checked the bush to find one, and then another, and then yet another after that! In total, I managed to find five on the bushes and here is a quick video tour of them in our garden. Apologies for the dodgy camera work!
I took a few close-up photos of the pupae too………
My attention was now drawn chiefly to the pupa on the wheelie bin. Here in Wootton, we get our black wheelie bin collected every two weeks and I knew that this pupa certainly wouldn’t survive another trip to the bin lorry. I checked it nearly every day as the days passed, getting ever closer to bin day, and I was starting to wonder what on earth I was going to do. Moving it would have to be a last resort as these butterflies ideally need to emerge hanging up. According to the books Brimstones take 14 days to emerge from the pupa so technically, it should emerge before the next collection, but has the recent cool drab weather delayed the development? By the day before bin day, the pupa has changed colour and was ready to emerge, you can see the wing through the sides of the pupa.
The bin day came! I checked it first thing in the morning and unfortunately, it was still very much inside the pupa. The bin men don’t normally arrive until midday so I left the bin where it was as I didn’t need to leave the house until mid-morning to give it some extra time. By now I was realising that the only option would be to cut the pupa off the bin and place it in a box with plenty of things for it to climb up and dry its wings out should it successfully be able to drag itself out of the pupa whilst laying flat. I assembled a tray with some lids carefully arranged at diagonals around it for just this purpose and then I found my penknife and unfolded the small blade. I really didn’t want to do this but it was realistically the only option. I went outside and walked around to the back of the bin to reach the pupa and the sight that greeted me made me carefully fold the small blade back into the body of the knife. There was no need for cutting as the adult butterfly had just emerged!
Wow, just in the very nick of time! However, this now did produce another conundrum. Butterflies can take a few hours to dry out their wings post-emergence and any moving could have serious consequences as if the wings become crumpled at this stage it will never be able to fly. So I decided to leave it. My partner, Nicky, checked and by late morning the butterfly had successfully flown. We missed bin day, and we now have to be extremely frugal with household waste over the next couple of weeks. But at least we have the knowledge that this very fortunate butterfly, one that was lucky to survive its ordeal, is flying freely somewhere and I would like to wish it lots of luck!