Monday 9 August 2021

Local Wildlife Sightings August 2021

 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


















UK Wildlife Sightings August 2021

 I made my annual visit on the 3rd to Wilstone, to find and photograph dragonflies and damselflies on the Grand Union Canal and Wilstone Reservoir. Lesser emperor dragonflies (a rare continental vagrant) had been reported flying on the reservoir at 'Cemetery Corner' a few days beforehand (and the following day!), but I could only find emperor dragonflies here and elsewhere around the edges of the reservoir. Neither could I find the female garganey here, in amongst the many teal on the reservoir, although I did see a kingfisher. I had better luck along the canal, where I was able to photograph a variety of damselflies including white-legged and willow emerald. Other insects seen along the canal included the rather attractive figwort sawfly.


Male White-legged Damselfly, Grand Union Canal near Wilstone, 3 August


Figwort Sawfly, Grand Union Canal near Wilstone, 3 August

On the 10th I paid my annual visit to Aston Rowant nature reserve (Oxfordshire), where I looked for and found my target butterfly - silver-spotted skipper. I travelled back via Ruislip, where I looked in vain for brown hairstreaks amongst the numerous blackthorn bushes in a nature reserve close to the perimeter fence with Northolt Airfield. I haven't seen brown hairstreaks for many years, but they are spreading in Middlesex. Maybe next year I'll go on the Butterfly Conservation walk (brown hairstreaks were seen here on an organised walk the following day).


Silver-spotted Skipper, Aston Rowant NR, 10 August

As the weather deteriorated again from mid-month onwards I switched my attention to birds, visiting RSPB Titchwell on the 12th where I saw an Arctic skua chasing terns off Thornham Point. On the way back I called in at Dersingham Bog where, apart from the ubiquitous stonechats and a red-banded sand wasp, I did manage to see a couple of grayling butterflies in flight. The butterflies roost here on the trunks of the scattered trees, but I was unable to find any to photograph in deteriorating weather.


Grey Plovers and Knot in Flight, Thornham Point, 12 August


Red-banded Sand Wasp, Dersingham Bog, 12 August

On the 24th (a rare bright day) I returned to RSPB Titchwell, looking for waders that were coming through on passage. I was able to add juvenile little stint and curlew sandpiper to my year list, whilst whimbrel and spotted redshank were also seen amongst nearly 20 wader species present on the reserve.


Juvenile Curlew Sandpiper (right) with Lapwing, RSPB Titchwell Marsh, 24 August

RSPB Local Group field trips started up again on the 29th with a morning visit to Kingfishers Bridge reserve, a relatively new reserve which is located between Stretham and Wicken in Cambridgeshire. We saw lots of waders (including greenshank and dunlin) on the main lake. We only saw one raptor during our visit, but it was a good one - a juvenile osprey!


Juvenile Osprey, Kingfishers Bridge NR, 29 August

I very rarely do long distance twitches, but the appearance of a 'mega', a white-tailed lapwing, tempted me to drive up to the RSPB Blacktoft Sands nature reserve near Goole in Yorkshire - a site that I haven't visited for several years - on the 31st. White-tailed lapwings are a big, gangly wader that breeds in western Asia and is seen on passage in far eastern Europe, so this waif is a 'mega' in the UK, with fewer than 15 records. The last 'twitchable' bird here was seen in 2010 and, not surprisingly, this was a 'lifer' for me. The bird performed well, albeit fairly distantly, during my visit and even flew briefly, revealing large white wing patches. An image of this yellow-legged wader is shown below. I hope that it manages to find its way back to its breeding/wintering sites, although it is so off-course that I doubt that it ever will......


White-tailed Lapwing, RSPB Blacktoft Sands, 31 August