A few more minutes of sunshine

Thursday 23rd August and the sun appeared in gaps between the numerous cumulus clouds. The day was warm and with little wind. Banded Demoiselle damselflies were still active over the lily pads with a group of 7 males chasing a single female ten meters along the river and back again several times. They soon lost track of the female which perched on the river bank nettles and continued chasing each other around the lily pads. More Banded Demoiselles were chasing in groups  over aquatic reeds on the Arun and several Beautiful Demoiselle damselflies  were also chasing over a separate patch on the river. Few have been seen for a while now, after an early appearance in May so it's good to see they are still present.

Butterflies were out with Speckled Woods all along the river where ever there was dappled shade, usually several together spiraling in close circles from down on the banks to high in the trees and back again. They also need to bask and usually choose bramble leaves to warm up on.

The star today was a fresh Small Tortoiseshell butterfly I encountered basking on the footbridge:

This Small Tortoiseshell butterfly was soaking up the warmth on

 a non-slip strip on the wooden boards of the footbridge, 

close to the nettles on the river banks.

Being late summer, this fresh butterfly will soon be seeking nectar, feeding up before choosing a suitable place to hibernate for the winter. Its name Aglais urticae indicates its essential foodplant -

common nettle (Urtica dioica) when in caterpillar form. Further along the river I found  Small Tortoiseshell caterpillars on the nettles:

Small Tortoiseshell caterpillars, probably final stage (they change 

skins 4 times as they grow). 

They create their own protective webbing to deter predators as they are very conspicuous, moving from one nettle plant to another, munching their way through the leaves and leaving bare stalks. They have to go through the chrysalis stage now, before emerging as butterflies.

Other butterflies seen today along the river banks were red Admiral, Comma Large White and Gatekeeper

In a drier area this Dark Bush Cricket male 

Pholidoptera griseoaptera was hiding. 

Being flightless, almost wingless it travels fast, springing a few feet over the vegetation using its very long legs. It has fine long antennae (unlike the Grasshoppers) and feeds on aphids, caterpillars, nettles

 and brambles. It usually stays out of sight as it makes a good meal for ground-feeding birds.

Birds seen today were Blue Tit  (31), Great Tit (15),  Woodpigeon (24), Collared Dove (2), Green Woodpecker (2), Chiffchaff (9), Willow Warbler (3), calling Nuthatch (5), singing Wren (2), Sparrowhawk, Goldfinch (5), Robin (2) Herring Gull (7) and Buzzard heard calling. It had been siesta time for all the small birds which started to become active again only when on my way back.  

Solar Powered Insects

The summer has appeared intermittently so far this year, with insects suddenly powered up as soon as the sun found a way through the clouds onto the river and banks. For aquatic insects such as Dragonflies and Damselflies the sun has to warm up the water before they can emerge. They also need vegetation to make their way out of the water,  climbing out to transform and warm up before taking to the air.

White-legged Damselfly Platycnemis pennipes in July

This was unexpected - a small, fragile damselfly which I saw making its way amongst the nettles on the riverbank then settling briefly on a blade of grass before flying off again. There was another not far away on the nettles which had probably emerged from the river at the same time.

This was confirmed as a White-legged Damselfly Platycnemis pennipes. It is of great interest as is very localised in Sussex and vulnerable to pollution and is found in clean flowing waters where there is plenty of mature vegetation. Its greatest threat is vegetation clearance. The fields alongside the river are important as well and need to be considered together with the river habitat in conservation plans. 

So good to see them here - they were still on the same stretch of riverbank the following day.

Small Skipper butterfly on thistle

Away form the damp river bank, in a patch of naturally occurring wildflowers, the Skippers appeared as soon as the sun shone, flying restlessly from flower to flower. They enjoy warm, dry weather and are increasing their range as the climate changes year by year.

Longhorn beetle Stranglia melanura

As soon as the Hogweed starts to flower all types of insects gather on the easily accessible nectar source, plenty for all, this one is larger than most.

Garden Bumblebee Bombus hortorum in thistle on the riverbank. 

Note its long tongue.

The Garden Bumblebee is a specialist, a long-tongued bee, foraging amongst deep flowers which other bees cannot reach. It has a longer face as well as long tongue and is in steep decline as flower-rich grasslands disappear from our county and the country as a whole.  

White-tailed Bumblebee Bombus lucorum on Bramble flower

Bramble flowers are very important sources of nectar for a large number of insect species and have the great advantage of flowering throughout the summer.  Brambles in warm areas flowering earlier and those in shadier locations flowering later, a constant food supply with berries ripening often on the same bush where buds and flowers are still present.

The Warblers in the Willows

Today, at last, a summer's day - warm, dry, with sunshine and a slight breeze. It would be a good time to have a quick look in the afternoon for butterflies, before the clouds moved in.

Sure enough, there was plenty of activity on the river banks with butterflies and dragonflies patrolling their territories without having to fly low to shelter from the wind or hang up under a leaf to shelter from the rain, or in the case of dragonflies, not bother to emerge at all.

Banded Demoiselle Damselfly male, resting on a favourite perch 

overlooking the river - a nettle leaf

Concentrating on the river bank damselflies and butterflies, looking down in all directions at the patrolling colours, brilliant orange, red, blue, green and more subtle shades of camouflage brown and buff, I became aware of soft calls from the direction of a river bank willow and - there being no wind to blow the leaves, slight movements in the branches must indicate the presence of birds. These proved to be a family party of long-tailed tits, mainly juveniles, busy collecting insects. They never stay to feed in one place for long and soon followed their leader to another, larger willow leaving me watching the first tree. A very smart adult willow warbler appeared and proceeded to feed on aphids on the undersides of the leaves with meticulous precision. It was finding plenty on each leaf, especially near the base stems, finishing with each leaf then moving on to the next, aphids still on its beak. Another movement, another willow warbler foraging, then some short 'hwit' calls indicated the presence of chiffchaffs nearby... and a glimpse of a whitethroat in the thicket, it may still have a nest with young down in the brambles below.
Still watching the same tree when suddenly more birds started to arrive,  flying out of the oak and ash trees, not together but singly, one after the other all landing in the willows on the bank. More and more, the total must have been around fifty, mainly blue and great tits and more long-tailed tits, intent on a share of the insects. They moved off again, leaving the willow warblers and chiffchaffs. Blackbirds and wrens were seen but not heard low down on the river banks.
Looking up, a common buzzard in moult leisurely glided on the thermals, with depleted feathers, it wouldn't fly so easily in bad weather.
Butterflies seen on the riverbank today were:  numerous Gatekeepers patrolling, keeping others away,  Meadow Browns, Red Admirals, Commas - more that usual,  Holly Blue, Common Blue, Small Heath, Speckled Wood in the shade, Large and Small Skippers in the sun, Red Admiral and Large White.
Damselflies on the river and bank nettles were: Banded Demoiselle, males still chasing low over the surface of the water, females on the bank vegetation and over the water,  Emerald Damselflies and some freshly emerged quite colourless damselflies perching on leaves whilst they gain strength and colour, a fast flying Brown Hawker dragonfly and a Migrant Hawker dragonfly perched on the tip  of a nettle in the sun, making sorties over the river, frightening off butterflies and hoverflies,  returning to the same high perch then flying off high into the trees.

A summary of the days since the previous record on 11th July and before the record on 9th August above:

Blackcaps were still singing during the second half of July but with songs reduced to short snatches and swifts were seen most days flying high over the river course catching insects carried up in the thermals with house martins flying at lower levels.
During sunny intervals butterflies, especially Red Admirals were seen flying strongly over the river bank vegetation, together with Meadow Brown, Small Heath, Small Copper, Holly Blue, Comma and Ringlet, 6 spot Burnet moths and Gatekeepers, the latter becoming more numerous. Certainly, when the sun shone, butterflies have been more numerous than last year along the river banks and Damselflies far more numerous. This in a summer where butterflies in general throughout the country have been scarce, due to the bad weather. Large numbers of Damselflies emerged on fine days, Banded Demoiselles especially numerous and a rare surprise on 20th July (see special report on Insects to come soon). The protection of the River bank vegetation here this summer has made a big difference.