Week 33: Mining, Growths & Another Argus

I should probably begin by confessing that I couldn’t resist another visit to the Brown Argus (Aricia agestis) colony. However, for those less inclined to pedantically scrutinise the wear patterns of battered butterflies, I’ll leave the results of that until the end. My visits this week to the rest of the Trust’s land have been very brief, which is a shame given the calm, warm conditions.

The Horse Chestnut trees (Aesculus hippocastanum) are looking at their best and worst. Their best, because they are laden with Autumn fruit (aka conkers!), and their worst, because the mining moth (Cameraria ohridella) has left no leaf untouched! Incredibly, although the damage looks decidedly vicious, the health of the tree is essentially unaffected. Its leaves will return as normal next year all set for another moth infestation, I expect. The light on Wednesday evening was beautiful, giving me the opportunity to enjoy the Horse Chestnuts (and horses) on Station Moor.


Early Autumn fruits are abundant now (blackberries on Bramble, berries on Hawthorn, hips on Roses, sloes on Blackthorn, elderberries on Elder etc) and acorns aren’t the only growths on the Dellfield Oak. A fresh eruption of the fungus Laetiporus sulphureus has appeared on the trunk less than 2 metres from the ground, on the east side, in an old wound. According to the internet, it tastes like chicken, hence its common name "Chicken of the Woods". However, I have no intention of wasting a good onion on finding out if wikipedia can be trusted or not.

Another conspicuous fungus which I photographed at the Brickworks is Tar Spot (Rhytisma acerinum) on sycamore leaves. It looks a lot worse than it is and again, like the mining moth, doesn’t do significant damage to the health of the tree.

Fancy some chips with your chicken?!

Tar Spot

Ok, to my guilty pleasure, indulged on Tuesday morning when the sun shone and the breeze was barely noticeable. A family party of tiny, trilling Goldcrests were in the trees as I made my way to the south-east side of Baker’s Wood at the Brickworks. A couple of Common Darter dragonflies flitted back and forth around the path. My eyes, however, were firmly focused on spotting the Brown Argus butterflies. I promised myself I wouldn’t spend more than about half an hour at this task, especially if I kept finding specimens I’d already seen on previous visits. The results were quite interesting (what?! they were).

I refound 6 specimens, 2 from last Thursday and 4 from Sunday, which just goes to show how little the Brown Argus wanders. I also found one more new specimen to add to the tally, making a total find of 14 individuals. I've christened this one Tatty, for obvious reason. Of the 6 refound, 3 had incurred further damage or wear, demonstrating just how quickly their condition deteriorates at this stage in their lifespan, even in a matter of 48 hours.

The Brown Arguses would turn up anywhere along this path

14. Tatty

Below are comparison photographs of the 3 refound butterflies, showing the changes in their wear patterns incurred in a matter of days. The original 13 butterflies can be viewed here.

3. Left Dink. The little tear in the left forewing has caused a small portion to subsequently fall off [shown left]









11. Worn. The trailing edge of the right hindwing has been damaged [shown below]

12. Big Notch. The damage to the left hindwing has worsened and there’s also now a small notch missing from the left forewing [shown right]












I think that's probably the last of my Brown Argus spotting (that wasn't a sigh of relief I heard was it?!). Knowing for certain that there are at least 14 individuals in the Brickworks colony is satisfaction enough. The peak count at Aldbury Nowers (the species stronghold) last year was 38 in week 22 (27/08/2013). The Nowers transect recorded 80% of the total number of Brown Argus observed across the whole of Hertfordshire and Middlesex last year. A count of 14 outside of that area is certainly significant and very encouraging.

Time for this week's horse photograph

Sorry, I meant Oak photograph