Sunday 31 August 2014

Week 32, Brown Argus Extra: Who's Who!

Spurred on by the calm sunny conditions this morning, I thought I’d have another go at assessing the size of the Brown Argus (Aricia agestis) colony at Bovingdon Brickworks. It’s been something of a painstaking task but also surprisingly satisfying, especially given the results.

OK, so we have the original 6 specimens from Thursday. For ease of identifying the individuals, I've named them after their damage/appearance as best I could. The gender pronouns are randomly chosen rather than indicative of the butterflies sex.

    1. Mr Perfect
    2. Right Nick
    3. Left Dink

    4. Mr Not Bad
    5. Double Damage
    6. Rear Right

And, today, I added a further 7 specimens to the count, producing a total of at least 13 individuals* on site. I only re-photographed (if that’s even a word!?) one of Thursday’s specimens today.

    7. Rear Left
    8. Ms Subtle
    9. Left Nick

   10. Right Little Dinks
    11. Worn
    12. Big Notch

    13. Worn Too

To put this total of 13+ into perspective, in 2013, the total number of Brown Argus recorded at other monitored sites nearby (excluding Aldbury Nowers, Tring, which is a Brown Argus stronghold) were as follows:


Tring Park, Tring
Miswell Lane, Tring
Lakeside Nature Reserve, Finchley
Heartwood Forrest, St Albans
Stocker’s Lake, Rickmansworth
Sherrards Park Wood, Welwyn Garden City      
Roughdown Common, Hemel Hempstead
Shrubhill Common, Hemel Hempstead
Harpenden Common, Harpenden  

There are more in the one small area at Bovingdon Brickworks than at all 9 sites combined last year! Moreover, it's a species which occurs in small, compact colonies and is "not a great wanderer, only travelling a couple of hundred metres, at most, from where it emerged.” It'll be great to see how this colony develops next year.

I will try to prise myself away from Brown Argus counting next week, I promise!

*NOTE 05 Sept 2014: I found a 14th individual on the 2 Sept 2014.

Saturday 30 August 2014

Week 32: Brickworks Brown Argus Colony

I wasn’t expecting much this week (and was actually just glad when it finally stopped raining!). Rain all day Monday. Rain most of Tuesday and fairly cool, breezy, cloudy days following. I spent a little time at Roughdown Common on Wednesday, trying to relocate or add a Chalkhill Blue (Polyommatus coridon) to the Brown Argus (Aricia agestis) of last week. I dread to think how many Common Blue butterflies (Polyommatus icarus) I chased down only to be disappointed. I couldn’t find the Brown Argus again nor add anything else to it.

Thursday, I thought I’d give Bovingdon Brickworks a try. Having spent a couple of hours hunting Brown Argus the previous day, I couldn’t quite believe my eyes when, within a few minutes of arriving, I’d found one at the Brickworks. One turned into two, which turned into three, which continued to rise until I was trying to follow/check/photograph at least six different butterflies. The conditions were such that they weren’t settling for long and so my best bet for identifying each individual was to photograph them the moment they stopped moving and then analyse the shots when I got home. Most of the specimens were quite worn so I was really chuffed to find one which was in good condition.

Bown Argus (Aricia agestis) [Specimen 1]

Below are the other five individuals that I was able to track down (with their identifying marks/damage highlighted). I know that at least a seventh got away and I wouldn’t be surprised if there were a few more besides. The fresher Specimen 1 is quite interesting and it does make me wonder if it is from a second brood, from on site. Either way, it is an extremely scarce species locally, not reported at this site previously and I am very much hoping that this small colony is a sign of things to come. It is located in the area of the Brickworks that I only discovered recently (see modified Buddleja location map here).

    Specimen 2
    Specimen 3
    Specimen 4

    Specimen 3 & 4 (Male & Female)
    Specimen 5
    Specimen 6

Whilst my head is full of Brown Argus and Common Blue butterflies (what a nice picture that conjures up! Butterflies for brains), I thought I’d put together a quick guide to separating the 2 species, especially the female Common Blue from the Brown Argus. The Common Blue butterfly, featured below showing the upper wings, is one I photographed alongside the Brown Argus on Thursday. It’s very worn but you can just make out the remnants of blue scales and, of course, the lack of dark spot in the forewing. The dark forewing spots alone aren’t diagnostic for Brown Argus so it’s important to note an absence of blue scales and/or the underside spot arrangement.

Ok, enough of Brown Arguses! What else? As I walked through the woods, on my way to the rest of the Brickworks, a little Nuthatch was calling from the trees and I could also hear at least 2 pairs of Bullfinches. The Emporer dragonfly that’s been patrolling that area for the past few weeks flew in close to take another look at me. Elsewhere, the number of Speckled Woods (Pararge aegeria) on site is impressive. There must be at least 30 individuals. I was also excited to find 5 Red Admiral butterflies (Vanessa atalanta), all in excellent condition. I’m guessing these are second brood rather than the original migrants of early summer.

Finally, I should round things off with this week's Oak photograph. It feels rather uninspired but the light/weather/my energy etc haven't permitted anything else…

Sunday 24 August 2014

Week 31: Butterfly Finale & Next Gen Bugs

I had my first blog-related nightmare this week. I dreamt that I arrived at Dellfield only to discover that over night there had been a kind of landslide/sink hole catastrophe. The whole meadow had sunk by about 4 foot. The Oak and Scots Pine had been completely uprooted and lay destroyed, on their sides, as if gunned down. Part of Hay Wood had slipped down the hillside and the whole area was unrecognisable. I couldn’t quite believe what I was seeing but, with dawning realisation, I actually began to cry. I guess over the past 8 months, Dellfield, the Oak and the Pine have become like old friends. Let’s hope I’ve not been blessed with the gift of prophecy!

Monday morning, I decided I’d concentrate my efforts on Bovingdon Reach meadow at Westbrook Hay. A group of about 15 Swallows were flying less than a foot above the ground, chattering to one another and searching out insects. My car thermometer read 13 degrees Celsius so it felt a little chilly although the sun did occasionally find its way through the banks of grey cloud (see photograph above for grey cloud proof!).

My first find was an immature (mid instar) Bronze Shieldbug (Troilus luridus) on Hawthorn berries. It’s a predatory bug which feeds on other insects although the nymphs (immature stages) also feed on plants. It occurs widely across the the UK but I’m not sure how common it is in Hertfordshire. There’s one generation per year. If you're interested, you can find pictures of the adult here.

Next up was a Hairy (or Sloe) Shieldbug (Dolycoris baccarum), so called because, well, it’s covered in hairs. At around 11-12 mm in length, it's twice the size of the tiny little Woundwort Shieldbug of Week 19. “It overwinters as an adult, emerging in the spring. Larvae, which are also hairy, may be found on numerous plants, particularly those in the Rosaceae. The new generation is complete from August onwards.

"It's common and widepsread in many habitats throughout Britain, particularly hedgerows and woodland edges, becoming scarcer and mainly coastal in the north”. It was a new species to me so I was chuffed to encounter it. I'm not sure if this is a fresh adult from this year or one from a previous generation. It's also just beginning to lose its lovely purple summer colouring and adopting its duller, brown winter hues.

Hairy Shieldbug (Dolycoris baccarum)

Finally, as I made my way towards Hay Wood, I spotted a Small Heath butterfly (Coenonympha pamphilus). These seem to be very scarce locally and I think this was only my second sighting this year (the first, I think, being a fleeting view at Roughdown Common, late Spring/early Summer). Anyway, I was pleased to manage a photograph this time before I lost it again. The larval food plants are grasses, specifically Bents (various) (Agrostis spp.), Fescues (various) (Festuca spp.) and Meadow-grasses (various) (Poa spp.).

Tuesday was a little warmer and much sunnier. Further Roughdown was covered in the white frosting of Eyebright and the purple splashes of Marjoram. Common Blue butterflies aplenty. I keep hoping I’ll come across a Chalkhill Blue or some other chalk plant loving species. Roughdown Common always feels like a habitat full of promise. And….it is...

A couple of immature (late instar) Dock Bugs (Coreus marginatus) were together on a bramble leaf (photographed left), up on the south-west side of Lower Roughdown. And, after wandering the bank, bordering the A41, I eventually spotted what I suspect will be this year’s butterfly finale, a species I was extremely pleased to find and one which just goes to prove the potential of this site. A Brown Argus (Aricia agestis). Having corresponded with a couple of experienced, local butterfly recorders, it seems that the Brown Argus is another local scarcity. Two were observed in 2012 at Roughdown Common, none last year.

Colonies of Brown Argus butterflies are generally found on chalk or limestone downland, where the primary larval food plant, Common Rock-rose thrives. Adults feed on Marjoram (Origanum vulgare) as well as Ragwort (Senecio jacobaea), Thyme (Thymus polytrichus) and White Clover (Trifolium repens). Roughdown Common certainly has the habitat to support this species but it’s obviously still only 1 or 2 specimens, if we're lucky.

Butterfly Finale - Brown Argus (Aricia agestis)

Project 2014 was never meant to be a scientific monitoring or recording of species around the Box Moor Trust sites. It was much more about enjoying the land and just seeing what turned up. However, I think that the Brown Argus was the 26th species of butterfly I’ve seen on Trust land this year, which speaks volumes to the quality of the developing habitat. According to Herts and Middlesex butterfly records for 2013, there are a total of 35 possible species present across the counties. Those I've not seen at the Box Moor Trust sites this year (so far):
1. Grizzled Skipper
2. Clouded Yellow
3. Purple Hairstreak
4. White-letter Hairstreak
5. Small Blue
6. Chalkhill Blue
7. White Admiral
8. Purple Emporer
9. Dark Green Fritillary
Species I have seen at the Box Moor Trust sites this year:
(if I saw them at one site only, I’ve indicated that [BW = Bovingdon Brickworks; RD = Roughdown Common])

1. Brimstone
2. Comma
3. Small Tortoiseshell
4. Peacock
5. Holly Blue (RD only)
6. Green Hairstreak (RD only)    
7. Red Admiral
8. Orange Tip
9. Small Copper  

10. Common Blue
11. Dingy Skipper (BW only)    
12. Large Skipper
13. Small Skipper
14. Essex Skipper
15. Meadow Brown
16. Ringlet
17. Marbled White
18. Speckled Wood  
19. Gatekeeper
20. Green-veined White
21. Small White
22. Large White
23. Painted Lady (BW only)
24. Silver-washed Fritillary (BW only)
25. Small Heath
26. Brown Argus (*)  

Still time for a Purple Hairstreak at Roughdown so I'm keeping my eyes peeled!

*NOTE 2 Sept 2014: Following the Brown Argus at Roughdown Common, I then found a colony of at least 13 individuals at Bovingdon Brickworks.

Friday 15 August 2014

Week 30: Frayed Fritillary, Painted Lady & Beautiful Buteo

I feel a bit like the weather this week…throwing the lot at you! Variety is, of course, the spice of life and you won’t get wet, I promise. In between light showers, pelting rain, darkness, sunshine, gusts and calm, I slotted in a few Box Moor visits. I split my time between Westbrook Hay and the Brickworks. I was very pleased to have the opportunity to photograph and film one of the Hay Wood Common Buzzards (Buteo buteo). Often, they are circling high over head or on an obscured perch but I got lucky on two occasions this week. One particular bird enjoys sitting in an Oak on Preston Hill (photographed below) or in one of the trees on the fringe of Hay Wood (where I filmed it).

I rarely visit Westbrook Hay without seeing and hearing at least 1 bird, frequently 2 and sometimes more. It’s ideal habitat for this handsome raptor, which nests on the edge of woodland but feeds on prey mainly found in open countryside. They hunt by sight and the fields surrounding the wood are a bit like the local take-away. I mentioned in an earlier post that the birds eat worms but the rampant rabbit population is almost certainly what sustains them at Westbrook Hay, although their diet is varied. During the 1950s and 60s the UK Buzzard population decreased dramatically as a result of myxomatosis decimating the rabbit population. Thankfully, both species recovered and both seem to thrive around Hay Wood. Buzzards mate for life, the male performing a spectacular aerial display at the beginning of Spring. He’ll repeatedly rise high into the sky, turn and then plummet downwards in a spiralling, twisting, turning motion, known as “the roller coaster” apparently. Mmm...I probably should have omitted that last fact since my video clip is the opposite of dramatic and enthralling. Ah well...

From birds to butterflies and over at the Brickworks I struck lucky again. An undamaged Painted Lady (Vanessa cardui) butterfly, a migrant species originating in North Africa. I’m not sure how likely this particular specimen is to have come from Africa. I suspect it’s probably one of the next generation, brooded on the continent. Either way, fantastic to see and the first record for 10 years for the area!

Painted Lady (Vanessa cardui)

I returned to the Brickworks on Wednesday morning, hoping the sunshine might bring out some interesting insects. Still plenty of Common Blue butterflies, Meadow Browns, Gatekeepers, Speckled Woods, Peacocks, a Red Admiral and a Small Tortoiseshell. Every visit, I check the Buddleja at the NE end of Baker’s Wood. Finally, this week, on my return journey, high up, nectaring on one of the few remaining flowers, I spotted a tatty orange butterfly. I was expecting it to be a worn Comma (Polygonia c-album) but through binoculars I could see it was more likely a Fritillary species, possibly a Silver-washed (Argynnis paphia). I grabbed my camera, fired off 7 shots and it was gone, fluttering up into the trees and away.

On 22nd June, Martin Parr had briefly seen a Fritillary species at the Brickworks but it had zoomed off before he could ID it. There’s a good chance that this week’s extremely worn, male Silver-washed Fritillary is the same specimen Martin observed. When I returned on Thursday, I relocated it not far from the Buddleja and simultaneously discovered an area of the Brickworks I didn’t know existed. On the SE side of Baker’s Wood there’s an expanse of open scrub with a number of substantial Buddleja bushes, two in full sun, towards the southern end (map here). I really wish I’d found these 2 months ago and it’s likely that the Fritillary and other butterflies were here in abundance. One to keep a close eye on next Spring/Summer, I think. Oh, and a big yellow butterfly came careering past me but never settled, disappeared up in to the tree canopy and I couldn’t rule out Brimstone. Hopes for my first Clouded Yellow went with it. Another day perhaps…

Silver-washed Fritillary (Argynnis raphia)
 The first record of this species in the Bovingdon area

From fauna onto flora. I have been meaning to include this tiny, weeny flower in a blog post all summer. It's approximately 4mm wide and best viewed with a magnifying glass (deerstalker hat is optional)! This week, I finally came across the perfect specimens at the Brickworks and couldn’t resist photographing them. It is the cheerfully named Eyebright (Euphrasia species), so called because it was traditionally used to treat eye infections, although I could easily believe that the vibrant, pretty little flowers were inspiration enough for its name. It is another semi-parasitic plant (like the Yellow Rattle (Rhinanthus minor)), keeping vigorous grasses at bay. It’s also a calcareous soil indicator and commonly found on rough grasslands - there’s plenty around the Box Moor Trust sites, particularly at Roughdown Common. It is easily missed but, up close, it really is beautiful.

Eyebright (Euphrasia species)

Finally, the moody skies of Dellfield over the Oak and the Scotts Pine. This was taken just after a shower had passed through on Monday (yes, I did get wet).

Friday 8 August 2014

Week 29: Watch Out, Frogs About!

It is now peak season for Clouded Yellow (Colias croceus) and Painted Lady (Vanessa cardui) migrant butterflies and they could turn up anywhere. I spent a morning at the Brickworks searching. If nothing else, I hoped I might come across a partial second brood of Dingy Skippers or my first Hawk-moth species but I struck out on all counts, and, instead, as I walked the shaded path back towards the Buddleja, I narrowly avoided the utter horror of standing on a substantial soft-bodied creature. A glistening, vital Common Frog (Rana temporaria). Unfortunately, it didn’t unleash its long, sticky tongue to catch any insects whilst I was watching but it did hang around for some photographs.

At both Dellfield and the Brickworks, there are good numbers of Common Blue butterflies (female, below, left) and each site had at least one fresh Small Copper butterfly (below, right). Other flutterers included Meadow Browns, Speckled Woods, Gatekeepers, Small Skippers, one or two Small Tortoiseshells; Southern Hawker and Emperor dragonflies; and a couple of very worn five-spot Burnet moth species.


Every pair of socks I own and quite possibly my walking shoes as well is in danger of hot-housing the development of miniature wild flower and grasses meadows. No matter how carefully I tread, or the number of times I stop to empty my shoes, I always come home from Box Moor outings with shoes and socks full of seeds from the meadows and moors. I don’t think that’s quite the intended outcome but short of wearing wellies all summer (and cooking my feet) it's unavoidable.

Out on Bovingdon Reach this week, during another inadvertent seed collecting mission, a juvenile Green Woodpecker was digging for ants. A small group of House Martins were catching insects over the meadow and back at Dellfield, a juvenile Great spotted Woodpecker stayed still long enough for me to grab a distant shot. It's great to see both woodpecker species have bred successfully this year. Earlier in the week, I’d caught a female Green Woodpecker perched on a fence post at the pond on Preston Hill. The very short video clip below is a little shaky as the camera was resting on the fence railings (no tripod to hand).


Finally, this week's Oak photograph…