July 9th-15th: week of the hairstreaks

I had a quick scoot around Brent on Saturday morning before taking the 297 bus to Perivale, just round the corner from Horsenden Hill for my second Lepidoptera field trip of the week. This one was led by David Howden and he showed us the contents of his overnight mothing to start with. I recognised quite a few species from when I used to trap but there were a few new ones including a smart Rosy Footman.

Rosy Footman

Once we’d had a quick look, as the plan was to spend more time with them at the end, we went for a butterfly walk, mainly to look for hairstreaks. It didn’t take long to find our first Purple Hairstreaks but there were several novices in the group, some of whom didn’t have any optics so we spent quite a lot of time trying to get everyone to see a perched individual. Directions of 'it’s on that leaf below the nibbled leaf' don’t work that well when looking at an oak tree with thousands of nibbled leaves!

Eventually we moved on to the row of elms where the other target, White-letter Hairstreak, is usually found. We saw a couple in flight before one landed and we went through a similar process of trying to get the group onto it which most people managed.

Spot the White-letter Hairstreak

I left the walk at this stage rather than go round the whole site as I had just come for the moths and hairstreaks. As I waited for the bus a Buzzard flew over.

I spent the rest of the week birding at Brent Res as it was pretty quiet elsewhere in London. After last week’s Red-necked Grebe arrived I had hoped for further signs of the autumn migration but in a similar vein to the fabled Swallow of spring it seems that one grebe doth not an autumn make.

It was also the start of the heatwave and rather too hot to travel far anyway. I did a butterfly transect at Brent and found my own Purple and White-letter Hairstreaks. The latter are usually seen along the same stand of elms every year but I didn’t see any there last year so it was good to know they’re still around. I was lucky enough to discover a Purple Hairstreak low down for a change which was much better for photography despite it having a bite out of its wing.

Purple Hairstreak

Wader numbers slowly climbed during the week and by Friday there were 14 individuals: 5 Lapwing, 5 Common Sandpiper and 4 Green Sandpiper. Hopefully it won’t be long before there’s something different like a Blackwit or at least a Redshank at Brent, whilst, further afield I'm hoping for a repeat of last year when I saw two Pec Sands in London.