So, on 10th July I drove back to take another look. I was very relieved when I arrived that it was a lovely sunny, still day, so I set of up the mountain from the Hoya de la Mora car park.
A little further up the mountain I noticed a subtle change in the shade of blue and realised that I was now walking amongst Escher’s Blues, Polyommatus escheri. I was interested to notice that they were in discrete colonies, whereas on previous occasions I have seen these two species sharing the same space.
I continued up the mountain to an area where I had seen Zullich’s Blues, Agriades zullichi, in the past. I spent some time searching the area, with little luck. The ground seemed quite churned up, as if cattle had been grazing there on the very sparse vegetation. Certainly when I look back at pictures taken in the same area two years ago, it was a lot greener then.
And two or three Painted Ladies, Vanessa cardui.
Finally, I saw a Zullich’s Blue. They are very difficult to follow, as they fly low and blend into the background. Those that I saw looked very worn, but just as I was about to leave I saw a fresher-looking female. I was delighted to see this lovely butterfly again, but it is a little concerning that I only saw five individuals. Two years ago I estimate seeing more than 15 in this same location.
Occasionally I would see a Small Tortoiseshell, Aglais urticae, or Wall Brown on the more rocky slopes.
Down at the stream and along the wet grassy areas, where last year I had seen several Meadow Fritillaries, there were surprisingly few butterflies this year. I crossed the stream and searched a scrubby area, which had looked good from a distance, but amazingly there were no butterflies there, other than a couple of Small Coppers, Lycaena phlaeas.
On my way back to the car I saw a couple of Small Whites and a long chase eventually allowed me to identify a Bath White. These white butterflies reminded me that I hadn’t seen any Apollos this trip. Just as I thought that, one flew past me and glided down the hill side. What a difference from two years ago when I saw so many.
Towards the end of my walk, I was surprised to find a snow bank blocking my route. I diverted around it and rejoined the path on the other side, which was wet with snowmelt. I was delighted to see some butterflies puddling on the path.
There were two Cardinals, two Small Tortoise shells and three blues.
The blues turned out to be a Common Blue, a Nevada Blue and an Escher’s Blue, demonstrating nicely the subtle differences between the species.
Certainly, there was a lot more snow around, so possibly it had been cooler than in previous years. I also noticed that there were more cattle and goats than I had seen in previous years. Possibly they had grazed more of the wild flowers.
It is good to know that there are a lot of researchers working in the Sierra Nevada monitoring grazing and climate change and their impacts on invertebrates. It would be very interesting to talk to them and find out more about the long-term trends.