Relatively quiet weather at the start of the month allowed me to get out and about on Therfield Heath and also to visit various locations around Royston Town, looking primarily for butterflies, moths and other insects. Chalkhill blues were still emerging on The Heath and I also noticed several males around town, including one that flew rapidly along the road at the side of my garden and two in a small wildflower meadow alongside the Stile Plantation, where several common blue and brown argus butterflies, as well as 5-8 female or immature male common darter dragonflies, were also seen on the 4th. I am pretty sure that these were migrants from the population on The Heath, rather than individuals forming a separate colony. Several carrot seed moths (sitochroa palealis) were seen on The Heath and elsewhere. The caterpillars of this micro-moth (which is larger than most 'true' moths) feed on wild carrot plants, which are abundant in the area this year.
Recently-emerged Male Chalkhill Blue Butterfly, Church Hill, 4 August
Carrot Seed Micro-moth, Church Hill, 2 August
I saw my last of this year's marbled white butterflies on the 6th. The last dark green fritillary was also seen on the 6th, although this specimen was dead, having become entangled in a spider's web (image). Judging by the state of its wings it had had a good life and, after death, nature was ensuring that it was not going to waste.
Spider with dead Dark Green Fritillary Butterfly, Therfield Heath, 6 August
There was a noticeable influx of (mainly) lesser black-backed gulls into the region from the end of July. I used to think that these gulls stayed here through the late summer and autumn, feeding in the ploughed fields, but ringing recoveries show that they often stay only for a day or two before moving further south for the winter, with other gulls presumably arriving all the time to take their place. The first of the second generation of Adonis blues were seen on Church Hill on the 11th. One female was found which clearly showed the blue markings near the base of the hind wings, which distinguish it from the very similar female chalkhill blue. I have included its photo below, although the tiny blue patches are hard to see.
Female Adonis Blue, Church Hill, 11 August
Following the cold, wet spring the summer of 2021 has been, at best, mediocre. A feature has been the low cloud and northerly or north-easterly winds caused when a high pressure system is anchored to the north or north-west of the UK. The worst example of this occurred in the second half of the month when, with the exception of a few days, the sun completely disappeared. Combined with the wind and seasonally low temperatures, butterflies remained out of sight and I was forced to look for other invertebrates to photograph.
Moths
I don't have a moth trap as such but I found that, by leaving the bathroom window open and the light on I was able to attract several different species in to the bathroom. On the night of the 18th I managed to attract five different species, including brimstone, clay, riband wave and willow beauty. In all, eight species were identified, with a couple more 'unknowns'. In the local fields I also found a few others, including blood-vein moth. However, I have yet to see or attract a Jersey tiger moth locally, despite this species becoming quite common in my area in the last few years.
Blood-vein Moth, Therfield, 19 August
Brimstone Moth, My Bathroom, 18 August
Spiders and Grasshoppers
I've never paid much attention to grasshoppers before but, in the absence of flying insects, I decided to try to photograph and identify them on Church Hill. I found two species (there could be more), meadow grasshopper and field grasshopper. Unfortunately for the grasshoppers (but not for me), my movements caused grasshoppers to jump and become entangled in spiders' webs on two occasions. This allowed me to see how the spiders (a female wasp spider and a female orb spider) dealt with their prey, firstly wrapping the grasshopper in silk and then extracting the juicy bits through the victims' heads. If you find this rather gruesome, don't look at the image below! I found three female wasp spiders, with what was possibly the much smaller male on its own web, a short distance from one of the females. I don't think that I want to be re-incarnated as a grasshopper!
Meadow Grasshopper, Church Hill, 26 August
Female Wasp Spider eating a Grasshopper, 24 August
Meanwhile, in my local woodland I came across a rather unusual kidney spot ladybird (below)
Kidney Spot Ladybird, Royston, 18 August
Birds
I did not see any spotted flycatchers locally in July or August and I assume that their nesting attempts failed during a cold, dull spell in June when hardly any insects were flying. I only made a couple of visits to Hatchpen Farm during August, when I failed to see any yellow wagtails, so I don't know as yet whether this species bred successfully there in 2021. However, I did record juvenile long-tailed tits (a second brood??) in my garden and juvenile whitethroats, blackcaps, mistle thrushes and red kites nearby. A party of three ravens (family group?) flew over Church Hill on the 24th. A willow warbler, probably on passage, was calling at the bottom of Church Hill on the 9th. Undoubtedly my best sightings of the month came on the 19th, when a hobby flew over Mardleybury Lake and I later saw the two juvenile marsh harriers that had been widely reported at Deadmans Hill, as well as a merlin (or a very small peregrine!), distantly from the road between Wallington and Baldock. I visited the recently re-opened reserve at Lemsford Springs, where I managed to flush a group of seven green sandpipers (never to be seen again) as I walked round the reserve. A pair of grey wagtails were in front of one of the hides. Finally, I noticed that significant amounts of beech mast had been produced this year after a number of very lean years. Hopefully this will aid the survival of the few remaining local chaffinches and perhaps encourage wintering bramblings to stay in the area.
Grey Wagtail, Lemsford Springs, 17 August
Following several cool, sunless days I was on Church Hill on the 29th, looking for grasshoppers and other invertebrates to photograph, when suddenly the sun came out. Almost immediately, as if from nowhere, 25-30 Adonis blues appeared from the grass, mostly bathing in the sun. For 20 minutes they enjoyed the rare feeling of warmth before the sun disappeared again, not to be seen for several more days. I wonder whether insects suffer from depression?
Male Adonis Blue on Field Scabious, Church Hill, 29 August
