Thursday, 31 August 2017

Late August at Castle Hill LNR, Newhaven


I did the week 22 walk on Sunday 27th in what for Castle Hill was uncharacteristically calm weather. This made for good butterfly conditions along the clifftops and there was much activity for the time of year. I counted 366 butterflies and moths of 13 and 12 species respectively. This is not a bad haul, but is lower than the same week in the previous two years, when over 400 were counted. Week 22 has usually been the final week of abundant activity at Castle Hill, so we might find a drop in numbers next week.
Straw Conch (Cochylimorpha straminea)

I don't want to get too carried away with excitement, but there has been something special happening this year for the Small Heath butterfly. I have been recording more than 130 at Rookery Hill in Bishopstone on some days recently and, on Sunday, I recorded nearly as many Small Heaths in one day (96) as we counted in the six years between 2011 and 2016 (113 in total during this period). Both Dave Harris and the County Lepidoptera Recorder, Colin Pratt, have commented that this butterfly appears to have recovered to its pre-decline 1970 population level. Let's hope it is sustained in the coming years. Isn't it wonderful to have a success story for once when considering the plight of so many other species?!!

Amongst the moths, I recorded our first Straw Conch (Cochylimorpha straminea) in seven years at the reserve and saw more of the Common Grass Veneer (Agriphila tristella) than we've ever counted before in a single day. This moth is having a good season and has been seen in good numbers everywhere recently. This distinctive moth, which has a pale streak running along the length of its wing, flies out of the grass ahead of you when you walk along country paths in the late summer and lands a few metres ahead, parallel with a grass stem.

Purple Loosestrife
Other items of interest include some purple loosestrife found growing by the 'old pond' (Dave tells me this is a new plant species for the reserve list) and some birds including a female Wheatear, two ravens and a sparrowhawk all along the clifftop.

Amongst the photos I've included is a shot of a hazy Seaford Bay. This haze is the infamous cloud that affected people later in the day on the beaches between Birling Gap and Hastings. When the weather is settled and sunny, an accumulation of pollutants such as oxides of nitrogen and other volatile compounds react with UV in strong sunlight to create ozone at low levels. This 'photochemical smog' causes severe irritation to eyes, nose and throat upon exposure. Air quality data measured at the Lullington Heath station on the same day showed a large spike in ozone levels. Thankfully those people at Newhaven's West Beach were not so affected.

Hopefully there will be no such hazards for Dave during week 23.
 
 
 
Low-level ozone at Seaford Head?



Late summer colour in the Wassail Glade at Castle Hill LNR
 
 25 species (13 butterfly, 12 moth); 366 individuals.

Large White (Pieris brassicae) 21
Small White (Pieris rapae) 68
Green-veined White (Pieris napi) 1
Clouded Yellow (Colias croceus) 2
Speckled Wood (Pararge aegeria) 19
Small Heath (Coenonympha pamphilus) 96 – highest numbers ever seen at CHLNR
Meadow Brown (Maniola jurtina) 65
Gatekeeper (Pyronia tithonus) 1
Red Admiral (Vanessa atalanta) 6
Painted Lady (Vanessa cardui) 1
Small Copper (Lycaena phlaeas) 4
Holly Blue (Celastrina argiolus) 2
Common Blue (Polyommatus icarus) 25

Golden Pigmy (Stigmella aurella) leaf-mines on bramble
Bordered Carl (Coptotriche marginea) leaf-mines on bramble
Apple Leaf Miner (Lyonetia clerkella) leaf-mines on apple and cherry
Common Nettle-tap (Anthophila fabriciana) 3
Straw Conch (Cochylimorpha straminea) 2 – first site record since 2010
Straw-barred Pearl (Pyrausta despicata) 10
Rusty-dot Pearl (Udea ferrugalis) 1
Rush Veneer (Nomophila noctuella) 3
Common Grass-veneer (Agriphila tristella) 32 – best numbers ever seen at CHLNR
Common Carpet (Epirrhoe alternata) 1
Vapourer (Orgyia antiqua) 1
Silver Y  (Autographa gamma) 2
 

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