Gatekeepers and Goldfinches - the survey for July 29th 2021

 The survey for 29th July 29th 2021 revealed butterflies and dragonflies outnumbering birds, not unusual for high summer. This is of course what is seen and heard which is not indicative of what is actually present along the river.

It was windy and sunny, with a few clouds scudding across, The breeze was cool, from the south-west and the ground damp underfoot, with large puddles and good numbers of insects over the water. Grasses going to seed have been delayed this year due to the cold spring but Goldfinches were now happy with seedheads appearing, at least in sunny areas. The river was quite high with mud indicating that levels had been at least 0.5 meters higher. Comparing the presence of fruit now more visible on the trees, it was clear that some had been exposed to freezing winds, hail and late frosts when in blossom whilst most had escaped and were producing strong fruits. This depends each year on the timing of the different varieties coming into blossom and the location of the trees on banks and slopes. As with the the fruit trees, there are different varieties of Bramble and each hedge or clump was at a different stage of producing blossom and fruits. with instant attention from bees and butterflies. There was a good selection of grasses and wild flowers, with Knapweed, Thistles, Meadowsweet, Fleabane, Willowherbs, Vetch, Clovers, Seneecio jacobaea, Bird's Foot Trefoil and many more.

Fleabane has done exceptionally well this year, suddenly flowering after a few hot and damp days:

A Hoverfly on rain-battered Fleabane which attracts many butterflies.

This time the survey begins with butterflies: over 100 Gatekeepers were seen, chasing, being chased by other  species, along hedges and over grasses, nectaring on many of the wild flowers, rather late this year.

One Brimstone female was present and over 30 Large White and 4 Small White butterflies were seen, most in flight.

Two Comma butterflies were present in different areas, and only two Meadow Browns but 9 Ringlets in damper  areas. Two Holly Blues and one Small Blue were flying near one of the ponds with a single Speckled Wood in the shade. Four Red Admiral butterflies were on thistles near one of the drainage basins, one of them chased off by an aggressive  Gatekeeper.

Above - a female Meadow Brown butterfly in a faded condition having survived torrential rain. wind and sun. The upper sides are usually darker when young.  The low number seen may be due to the Meadow Brown butterfly sometimes roosting in the tops of trees and being exposed to this summer's bad weather.

Note that there were several Marbled White butterflies in the same area in mid July first seen here last summer 2020.   It's good to observe that they have reappeared this year!

Next, Dragonflies:

One strong-flying Brown Hawker, a Large Red Damselfly and three Migrant Hawkers were present

and very active.

The most numerous by far were the Banded Demoiselle Damselflies, many in the shelter of the steep  Arun river banks typically in the area shown in the photo on the previous post.

It was interesting to see several males clinging upside-down on different levels on a single reed peering onto the water surface below. More were perched on a tree log, coming and going, dashing out for passing insects.

Grasshoppers:

Largely unseen unless disturbed were hundreds of small Meadow Grasshoppers low down in the thick layers of the grasses on the river bank meadow, jumping to the top then falling back down under cover.

Bees of many types, Bumblebees and Honey bees were numerous as were Hoverflies.

Birds

Most numerous by far were the Goldfinches, more than 60, which were heard then seen in several groups, some flying across and landing in trees and thickets, where  they would sing together, juveniles included.  Along the river, Blue Ts (19 )and Great Ts (5) were moving amongst the trees mostly selecting insects as they went, a few calling. A call from a single Willow warbler was heard (not the song) and more than 20 Chiffchaffs were heard calling and most seen, making continuous contact with others. Perhaps they were forming flocks before migrating, although some will be overwintering here locally.

They are usually the first migrant birds to arrive here in the spring. A single Whitethroat was seen amongst the branches of a young tree.

Blackbirds and Song Thrushes had been late to commence their spring song this year but made up for in volume but have been very quiet during their moult season, only uttering alarm calls. Only 13 Blackbirds were seen and no song thrushes.

One or two were 'sunning' on the bramble verge while some were obviously still feeding young.

Usually the most numerous of birds heard singing along the river - the wrens were remaining very quiet - only 6 were heard or seen. Even fewer Robins were counted - three, they have not left but are in hiding still.

Three Blackcaps were visible in the thickets over the Arun where they are usually seen when they first arrive in the spring and are heard singing. They will probably leave soon, to be replaced with 'winter Blackcaps'-it is still thought that the birds that are seen here in the winter are not summer migrants which have decided to remain rather than migrate.

We have all seen large flocks of House Sparrows about but only 23 were seen today, quite vocal, but well hidden in the hedges. Starling numbers can vary a lot but 6 were counted and only three Herring Gulls seen flying across. 27 Woodpigeons were scattered in old oak trees and on the grass under them . There were 4 Magpies, 5 (moulting) Carrion Crows and one Jay in the same trees.

Finally a single Great Spotted woodpecker and two calling Nuthatches were seen.

There were signs of early plundering of Hawthorn berries and Hazel nuts neither being fully ripe at the time, but very plentiful.

More about Dragonflies and their habitat

 In the previous post the dragonflies described were Damselflies which are usually more commonly seen in late spring and mid summer whereas Dragonflies are more often seen later in the summer and into early autumn. The Damselflies in this area frequent slow moving rivers or slow-moving meandering sections, usually with plenty of green aquatic plants, green banks bordering green grassy areas. The most important features of their habitat are old and new branches dipping into or crossing the river water, slowing it down and providing warm sunlit surfaces to perch on - large old fallen branches are perfect for both damselflies and dragonflies, with hedges providing the ' hanging ' dragonflies with lookout locations. There are many suitable places  for river dwellers and fewer locations for pond dwellers unless the drainage basins retain water during the summer.

A perfect example of Dragonfly and Damselfly river habitat with sunlit perches - the fallen branches connecting the steep bank with the river. When the sun is at its highest the area can be quite crowded with active Odonata whilst the grassland and wild flowers at the top of the banks supports many butterflies in the height of summer flying together with exploring Odonata.

Other Odonata prefer ponds but as this area has no natural marshland and bog the ponds are restricted to 'created' ponds and drainage basins with planting to encourage wildlife.

It is here that we find the Skimmers - Dragonflies such as the Black-tailed Slimmer (Orthetrum cancellatum) in habitat with broad-leafed plants and usually stoney paths nearby. On hot days leafy perches are preferred! This Black-tailed Skimmer can just be seen flying low over a broad leaf at the top left, it's shadow more visible on the leaf below, wings outspread. 

In semi-shade this pond does not usually dry out and harbours frogs which translocate to many other areas nearby via vegetation and long grasses, escaping the attention of Grey Herons which also frequent the area. This Dragonfly also frequents the area of the river (see above) , coming back again and again to the same perch whilst hunting. The presence of butterflies can attract it to marginal grasses where it will catch and eat them. They will eat many types of insect, even Damselflies.

Often overlooked, unlike butterflies, Odonata are very fragile and their presence is completely missed in even slightly cloudy weather which leads to their habitat being lost to river and pond clearance work, summer mowing of wild grasses and plants, draining damp areas and allowing drainage basins to dry out.

The habitat that supports them is also vital for the survival of many other species. Complete colonies of these Odonata species can be destroyed in a few minutes, not just for that year but permanently. They will survive normal flooding after torrential rainfall but not the work of a machine such as a digger.

The river supplies its own diversity with meanders, shallows, slow flows, fast areas, clear water and muddy water, a variety of aquatic plants, a stoney bed and a soft muddy bed, steep banks and grassy banks, marginal trees old and young, sun and shade.

Dragonflies and their Habitat here

 Exceptionally erratic weather this summer (and it's not over yet) meant that the first sightings of some species were delayed or made in slightly different locations. As usual the first dragonflies to be seen however were the Beautiful Demoiselle damselflies in May (see the post for the survey of 27th May 2021). The sightings of Beautiful Demoiselle damselflies was followed almost immediately by the Banded Demoiselle damselflies : 

Here is a male Banded Demoiselle perched on a leaf with an excellent view over the river.

It is a spectacular electric blue with translucent wings marked with a black 'thumb print' which identifies it wherever it is seen.

Males are often seen in groups flying and chasing just above the river surface or perched on fallen branches, plants and twigs but occasionally fly off overland,  whilst the metallic green females spend most time away from the water  unless ovipositing (depositing eggs) on floating plants.

Here is a female Banded Demoiselle damselfly moving on a Nettle leaf   29th July 2021

The females have greenish wings unlike the female Beautiful Demoiselle damselfly which has dark brown wings:

 see below for an example which captures what you would see if you spotted a female Beautiful Demoiselle in flight!

(A photo of the male on a Dock leaf is on the post for the Survey for 27th May 2021).

What do you see in common on all these photos?

A variety of lush green vegetation which is essential for the survival of dragonflies and damselflies - both aquatic and bank/field plants. These are essential  for the whole life-cycle of these insects, providing climbing stems and shelter for dragonflies when in larva form in the river and their emergence from the water, then providing platforms for watching for passing insects, then for ovipositing.

In bad weather the plants will be used for shelter, in common with most other insects such as butterflies, grasshoppers and moths.

NB Damselflies are in appearance more fragile than 'Dragonflies', perching with wings held closed over the back in most. rather than held out at right angles to the back. Both wings, from and back are the same basic shape and the eyes are separated (see first photo on this post -  male Banded Demoiselle). 

Dragonflies (common name for all Odonata) but separated by the name Anisoptera (unequal wings) from the Damselflies Zygoptera (equal wings) have a sturdier heavier body shape and powerful flight, wings held out from body when perching, with hind wings a different shape from front wings.

More on habitats and dragonflies in the next post.....