I had a very interesting day on Saturday, when I was invited to join a group counting Grey Seal pups on the islands of Inchkeith and Inchmickery in the Firth of Forth. The reason I was there was to identify butterflies that they had seen hibernating in old underground military buildings in previous years. Both islands have a long history of military defense, but I hadn't realised that they are almost entirely covered in old military buildings of various ages.
Last year the group had noticed large "clumps" of butterflies on the walls and ceilings of some of the rooms. This year they were very disappointed that we only saw one or two butterflies at a time. However, I found it all very interesting.
We found a total of 77 Small Tortoiseshells, Aglais urticae, and 7 Peacocks, Aglais io, on Inchkeith and two more Small Tortoiseshells flew past us while we were looking at the seals.
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| Small Tortoiseshell |
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| Peacock |
These were the two species that I thought we would find, but I also wondered if we would have found a Comma, as they have done so well this year. I also wondered if any Red Admirals or Painted Ladies would have tried to tough it out here, rather than migrating south for the winter.
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| There are seven Small Tortoiseshells in this picture along with a Herald moth. |
The butterflies seemed to be quite specific about their requirements, only being found in the underground buildings. There were none in the tunnels or rooms with direct access to the outdoors. They were all in rooms that had just the slightest hint of daylight and no perceivable movement of air. When we searched rooms that were further underground we found nothing. So it seems that they had found locations with a nice steady temperature, but where they would be able to perceive the arrival of spring. I wondered how the butterflies had found these locations. Had they flown over to the island specifically to hibernate, or were they already resident there?
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| Mother Grey Seal keeping an eye on us. |
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| The pups were pretty sweet! |
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| Relaxed! |
The buildings on Inchmickery were all above ground and didn't appear to have any butterflies at all.
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| Inchmickery |
I would love to return another year and see if there are more butterflies. This year we had a cooler than normal August and September and a milder than usual October. This may have upset the normal behaviour of the butterflies. Had August and September been nearer their normal temperatures and the weather then quickly cooled in October, possibly more butterflies would have found their way into these buildings.
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| We were honored with a flypast of Pink-footed Geese. |
I now need to find similar locations on the mainland to see if butterflies are hibernating there. The islands will remain a little warmer over the winter than further in land, but the butterflies will have to hibernate somewhere.
It seems that the more I learn about butterflies, the more questions I have!
Those peacock butterflies seem to be camouflaged well. I love the seals!
ReplyDeleteThe underside of their wings is really well camouflaged, yet the top side is beautifully marked. The camouflage doesn't work so well against the whitewashed walls of the old buildings, though!
DeleteQuite fascinating Nick! What a great opportunity. Your seal shots are awesome! I'm quite excited you were able to check this out. Hopefully you'll find some closer to home you can keep an eye on.
ReplyDeleteI feel very lucky to have been invited along. It was a really interesting day and the weather couldn't have been better. I have a few ideas of places to check out for hibernating butterflies closer to home.
DeleteHow interesting to find some of the main nymphalids wintering in very specific conditions. I bet you had a ball that day and your future observations will be as interesting to follow :)
ReplyDeleteThe seals are so cute!! I wonder if you could pet the pup... he seems to be begging for it!!
All very exiting!
Keep well, Nick!
Noushka, it was a fantastic day. I wouldn't want to try petting a seal pup! Their mothers were not far away and they looked quite fierce. I bet even a pup would try to take your hand off!!
DeleteHi Nick,
ReplyDeleteYou got sea-legs, Nick! You are right about not petting the little sea-dogs, I have been scared a few times as I was brushed while swimming. I admit to thinking the same thing as Noushka though, you just want to pet the pups, they are so cute! The bunkers and buildings remind me of Panama. There were many old bunkers there and sometimes I got the nerve to go in and explore. I was always afraid of running into poisonous snakes so I was not comfortable and didn't stay long or go in far. I do remember things attached to the walls though.
I bet it was a little warmer in Panama, so no chance of anything hibernating in there!
DeleteWow!! I never imagined that butterflies would hibernate in such a place - but what do I know - you won't find any butterflies hibernating in Singapore! They remind me a little of roosting bats, hanging from the ceiling like that. Great findings too, on their specific preferences of hibernating places. :) Anyway it's great to know you're still hunting butterflies out even in winter! And, the seals are adorable. ;)
ReplyDeleteHi Jonny. Yes, still hunting! I have been thinking about places locally that could be used by butterflies to hibernate. So far I have found some in an ancient castle and in an old stone shed. I have a few more ideas of places to check out. It isn't quite like looking for butterflies in the summer, though!
DeleteIt is amazing how those butterflies hybernate there. I reckon they went there as adults, then mate there, but what will the larvae eat in that island? It seems to be devoid of nice plants for the larvae, it looks mostly rockies!
ReplyDeleteAndrea,
DeleteYes, this intrigues me too! I could see that nettles had been growing on much of the island, and that is what these species use as the caterpillar food plant. However, in the spring the island will be covered in nesting birds, so I wouldn't fancy the chances of any caterpillars! I imagine that many of the butterflies may fly to the mainland to lay their eggs, as it isn't too far as the butterfly flies! However, if they came from the mainland, how did they find the island in the first place? It is almost as though they knew that there were suitable buildings there to use to hibernate in.
Beautiful post.
ReplyDeleteHave a great day!
Thank you Robert.
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