Local Wildlife Sightings July 2022

 Invertebrates

I had to wait until the 2nd to see my first chalkhill blues on The Heath. By the 4th they had increased in number to perhaps 30-40 (all males seen) in the Old Rifle Range area, but surprisingly few were seen on Church Hill where marbled white, despite a big decrease in numbers, was still the dominant species. Once again, a very large colony of Essex skippers was located along a field margin on the Hertfordshire Way, south of Royston, with an estimated 100-150 individuals on the wing early in the month. Very few small skippers were seen in this area, although they were common elsewhere. Ringlet butterflies, which have a short flight season, peaked in the first week of the month. The commonest moths appeared to be 'grass veneer' moths, which were present in huge numbers at the bottom of Church Hill. Around 20 brassy longhorn moths were seen on and around field scabious plants, near the hospital, on the 4th. Some interesting hoverflies were seen on The Heath.

Small Skipper, Therfield Heath, 1 July

Male Chalkhill Blue, Therfield Heath, 2 July

I ventured to Scales Park (a large, privately owned area of mixed woodland near Anstey and Meesden, with a public bridleway running through the woods) on the 5th. I have seen purple emperor here, but had no luck on this occasion. However, a couple of male silver-washed fritillaries were seen including a relatively confiding specimen, which allowed me to take some photographs.

Male Silver-washed Fritillary, Scales Park, 5 July

Covid-19 finally caught up with me early in the month and forced me into isolation for a few days, although I did venture out on my own once or twice, looking for and photographing invertebrates in the fields around my house. On my return to The Heath, male and female silver-washed fritillaries (12th) and an unexpected clouded yellow (23rd) took my 'local patch' butterfly list up to 29, with only small blue (colony apparently on a private site to the east of Royston) missing. Chalkhill blue numbers rapidly increased on The Heath to an estimated 2,000+ as the 'heatwave' temperature continued to rise to a record-breaking 39C on the 19th. As temperatures cooled somewhat from the 20th numbers of second generation brown argus, holly blue and common blue started to increase. A second generation small copper on the Old Rifle Range was an unusual sighting on the 23rd. However, my most surprising sighting of the month was of a white-letter hairstreak in the back garden on the very hot afternoon of the 18th. Presumably this had come from one of the Elm trees in Green Walk Plantation (at the bottom of my road) - needless to say, this was a garden 'first' on a 'white-letter day'!

Mating Chalkhill Blue Butterflies, Therfield Heath, 18 July

Clouded Yellow, Therfield Heath, 23 July

White-letter Hairstreak in my Royston Garden, 18 July

The middle of the month saw the emergence of big numbers of six-spotted burnet moths in the area. Another long overdue local 'first' for me on the 18th was a Jersey tiger moth, seen a few hundred yards from my house. This species is spreading rapidly northwards and has been present in the Royston area for 2-3 years now. My next challenge will be to photograph this moth! On the 19th (yes, the hottest day on record) I visited Hertford Heath and Balls Wood, looking for dragonflies and purple emperor butterflies. I saw my first southern migrant hawker dragonfly (a recent 'Climate Change' import from southern Europe). Some excellent photographs of this individual have been taken, but mine were, unfortunately, not worth keeping. However, I did manage to photograph a scarce emerald damselfly (image below). The most unusual sighting was that of over 100 (I kid you not) purple hairstreak butterflies at ground level, both on the mud that was all that was left of the water in the dragonfly pools and in vegetation throughout Balls Wood. Perhaps the sun had become too hot for them to stay in the oak trees where they normally hide? Certainly, very few other butterflies were on the wing in temperatures that were rising towards 100F.

Scarce Emerald Damselfly, Hertford Heath, 19 July

Purple Hairstreak, Balls Wood (Hertford Heath), 19 July

Other Wildlife

A lesser whitethroat was amongst a number of warblers heard singing on The Heath on the 2nd and the 4th. This may indicate that they will attempt to raise a second brood. Sadly, there was no sign of any spotted flycatchers in the woods across The Heath, although I have yet to do a comprehensive search. Two ravens were seen when I visited Scales Park on the 5th (see above). I've recorded ravens here on a number of occasions - I assume that they nest in the woods. On the 16th I was doing a quick 'recce' for butterflies on the Old Rifle Range, in preparation for leading a Herts. and Middlesex Butterfly Conservation walk, when I heard once familiar purring coming from trees on the hillside to the west of the valley - a turtle dove! It is six years since I've recorded a turtle dove on my local patch. The bird continued to sing intermittently for 45 minutes and appeared on a couple of occasions, flying between bushes. I guess that this bird was a 'wanderer', although it is possible that it may have bred, unseen and unheard, locally. The bird was seen in the same area on the following day and there was another report later in the week, although I failed to record it on two further visits. The coot family (five young) was seen at Phillups Lake on the 6th and the 20th. The Canada goose family (three young) was also seen here on the former date and I was pleased to see a juvenile little grebe, together with its parents, here on the latter date. My annual swift survey, counting birds seen as I walked on the evening of the 22nd from my house on the southern edge of Royston to Tesco in the north, gave an approximate count of 85 birds, very similar to last year's total. It is, of course, impossible to get an accurate count of birds that are wheeling about rapidly, close to their nesting sites. Comparing with last year I guess that there were (sadly) fewer breeding sites available this year but that breeding success (in better weather) has been higher for this still declining species.

After a week away I walked up to Hatchpen Farm on the 31st, recording 14 corn buntings, three house martins and a swift there. A large flock of black-headed and lesser black-backed gulls was in a field on the Newsells Stud Farm estate, following light overnight rain. In the driest July on record (6mm of rain in Royston) I then got soaked by a shower as I walked home!