Brown Argus Foodplant & Emergence

A quick update on the Brown Argus (Aricia agestis) colony at the Brickworks. It’s located on the rough ground east of Baker’s Wood (the area surrounding the grid reference TL00790260).

Brown Argus (Aricia agestis), Bovingdon Brickworks, 21/05/2015

We've identified the presence of Cut-leaved Crane's-bill (Geranium dissectum) growing in shallow, nutrient poor soil on the top of the concrete slabs which now act as a pathway. This is the likely larval foodplant and is exactly the area the Brown Arguses were favouring last August. Being dependant on a low-growing, annual plant (rather than its typical perennial, Common Rock-rose (Heliantbemum chamaecistus), which grows on chalk and limestone soils) puts the colony in rather a precarious position. This is very well explained in the short article by Roger Kemp, HERE.

Brown Argus colony location

Cut-leaved Crane's-bill (Geranium dissectum), Bovingdon Brickworks, 13/05/2015

Cut-leaved Crane's-bill (Geranium dissectum), Bovingdon Brickworks, 13/05/2015

Having spotted the first fresh adult on 10/05/2015, I was very pleased to find 7+ Brown Argus enjoying the warm, sunny conditions this morning in the same area.

Brown Argus (Aricia agestis), Bovingdon Brickworks, 20/05/2015

Other butterflies and moths of note: Orange tip (2m, 1f), Large White (m & f), Small White, Green-veined White, Small Tortoiseshell (3), Peacock (2), Dingy Skipper (3), Common Blue (2m), Burnet Companion moth (1), Silver-ground Carpet moth (2).

In other news... 

...another Box Moor Trust volunteer and experienced butterfly surveyor, counted at least 18 Dingy Skippers on site on 13/05/2015, along with the first record of a Green Hairstreak. Very encouraging indeed!

Dingy Skippers Emerge

Should your heart’s desire be a Dingy Skipper (Erynnis tages), you’ll be hard-pressed to find one in Hertfordshire, unless you visit one or two key sites. Although distributed throughout Britain and Ireland, colonies are often small and localised, and numbers generally have declined rapidly in recent years. In Hertfordshire, it’s as rare as the Green Hairstreaks (Callophrys rubi), according to the results of the 2014 transect survey. There are small populations at Aldbury Nowers (6 recorded in 2013; 12 recorded in 2014); Shrubhill Common (4 recorded in 2014) and Tring Park (1 recorded in 2014).

Last year, I noted 3 possibly 4 Dingy Skippers at Bovingdon Brickworks, which is pretty good going given the other county records. Adults emerge the first week of May so I optimistically visited the Brickworks at the end of last week. No luck. But, today, I was really chuffed to find 2, although keeping track of them and getting even one photograph proved tricky. Best effort below - hopefully there will be other opportunities in the coming weeks.

Dingy Skipper (Erynnis tages), Bovingdon Brickworks, 4 May 2015

There’s no sign yet of last year’s Brown Argus (Aricia agestis) colony. The only other butterflies I saw today were 3 Small White (Pieris rapae), 5 Peacock (Aglais io) and 1 Small Tortoiseshell (Aglais urticae). Not great going for warm conditions (15°C) with sunny spells.

I should also mentioned the Common Whitethroats are back on territory, singing away.