17 Jun 26

The Flash and Priorslee Balancing Lake

17.0°C > 20.0°C: Some sunny spells after early rain. Light / moderate south-westerly breeze. Very good visibility.

[Sunrise: 04:46 BST]

* = a species photographed today
! = a first sighting of the species this year
$ = a new species for me in this area

A "wet weather circuit" starting at The Flash after the rain had stopped and the school-run was over.

Priorslee Balancing Lake: 10:25 – 12:00

(143rd visit of the year)

Mostly watching from the dam-top area and avoiding much of the wet vegetation. The model boat club were using the south-west area.

Bird notes:
- the seven Greylag Geese goslings with two extra adults remain.
- the pen Mute Swan was with the cob out on the water all the while. No cygnets.
- there are four pairs of Great Crested Grebes. The second pair to have young did not reveal how many there were on the adult's back. The original pair had just one juvenile in the water briefly. The other to pairs seemed to be disputing who owns what part of the lake.
- unexpected was the first returning Common Sandpiper: likely a failed or non-breeding bird. While it may seem an early date I note from my records that in 2023 I recorded one on 04 June and also in June in two earlier years.
- I have noted before that House Sparrows frequently visit the dam-face at this time of year. Previously they seemed to be flying from and to the main Priorslee estate where good number can be heard. Recently I have remarked that the new estate to the East of Castle Farm Way is hosting this species. To add to confusion I noted at least four birds flying off South and away over the M54.

Bird(s) noted flying over here:
- 3 Wood Pigeons
- 5 Jackdaws
- 3 Rooks again

Counts from the lake area:
- 4 + 7 (1 brood) Greylag Geese
- 2 Mute Swans
- >18 (?♂) Mallard: seen at a distance only
- 1 Moorhen
- 28 + 2 (2 broods) Coots: seen at a distance only
- *8 + >1? (? broods) Great Crested Grebes: see notes
- 1 Common Sandpiper: in flight only
- 1 Grey Heron

Hirundines etc. noted:
- 4 Swifts
- 1 Barn Swallow
- 1 House Martin

Warblers noted: I did not walk around; the following species were heard
- Chiffchaffs
- Reed Warblers
- Blackcaps

Also noted:
A visit to a vegetated area at the East end put the following species in today's log:

Butterflies:
- 1 Red Admiral Vanessa atalanta
- 1 Painted Lady Vanessa cardui

Moths:
none

Bees, wasps etc.:
- Tree Bumblebee Bombus hypnorum
- Common Carder Bee Bombus pascuorum
very few bumblebees around

Hoverflies:
- *!Dark-winged Wrinklehead Chrysogaster solstitialis
- *Marmalade Hoverfly Episyrphus balteatus
- Common Dronefly Eristalis tenax
- Migrant Field Syrph Eupeodes corollae [Migrant Hoverfly; Migrant Aphideater]
- *Humming Syrphus Syrphus ribesii [Common Flower Fly]
- *Glass-winged Syrphus Syrphus vitripennis [Black-thighed Flower Fly]
- Syrphus sp. S. ribesii / S. vitripennis / S. torvus
- *Common Twist-tail Sphaerophoria scripta [Long Hoverfly; Common Globetail]
- *Pellucid Fly Volucella pellucens [Pied Plumehorn; Great Pied Hoverfly]
dozens and dozens of Marmalade Hoverflies. Otherwise little variety

Damsel- / Dragon-flies:
- Common Blue Damselfly Enallagma cyathigerum [Common Bluet]
- Blue-tailed Damselfly Ischnura elegans [Common Bluetail]

Other flies:
- Black Snipefly Chrysopilus cristatus: once again all males
- long-legged fly Dolichopus ungulatus or similar
- greenbottle Lucilia sp.
- *$ Dark-winged Flesh fly Nyctia halterata
plus a few unidentified flies

Bugs:
- mirid bug Deraeocoris flavilinea

Beetles:
- larvae and *pupa of Harlequin Ladybird Harmonia axyridis
- Harlequin Ladybird Harmonia axyridis var. succinea
- *pollen beetle Meligethes sp.
- *!Common Red Soldier Beetle Rhagonycha fulva [aka Hogweed Bonking-beetle]

Note:
Some useful feedback from Martin Adlam (thanks) suggests I was correct that the unidentified moth on the ceiling of the Priorslee Avenue tunnel was one of the Minor moths Oligia sp. It is most likely to have been a Tawny Marbled Minor O. latruncula. The literature notes that all members this group cannot be ascribed safely to a particular species without examination of their genitalia. It will therefore remain as unidentified.

One I will have to let pass. Dead-centre is a very blurry bird hiding in the reeds. It was taken at extreme range and edited as best I can.. I noted one of the pair of Great Crested Grebes with the juvenile on the water chase a smaller bird, forcing it dive and swim away. It looked "grebe-shaped" and it just might be a Little Grebe, a species I have (surprisingly) not recorded here this year. Nothing emerged to clarify what I had seen.

My first Dark-winged Wrinklehead Chrysogaster solstitialis of the year. I will have to get closer to this hoverfly to show the "wrinklehead".

There were very many Marmalade Hoverflies Episyrphus balteatus with very catholic tastes. Feeding on yellow flowers...

...red flowers...

......blue flowers...

...and white flowers. Here feeding on Common Hogweed Heracleum sphondylium. If I had thought about it I could have photographed the other flowers separately and used my apps to plug my poor botanical recognition. Not also how variable this species of hoverfly is.

Here an exceptionally dark variant.

A rarity: a female Syrphus hoverfly showing its hind leg clearly. The leg is all-yellow making this a Humming Syrphus S. ribesii.

Another with the legs in full view. This a Glass-winged Syrphus Syrphus vitripennis illustrating its Obsidentify name of Black-thighed Flower Fly.

This hoverfly had me scratching my head and exploring Steven Falk's Flickr photos. I concluded it is a female Common Twist-tail Sphaerophoria scripta that belies the species' alternative name of Long Hoverfly. Females do not look "long". They also have narrower and more horizontal yellow markings than the males (and here at least, paler yellow marks). I mostly see males.

A very distinctive hoverfly: a Pellucid Fly Volucella pellucens.

The final larval stage of a damselfly soon to look...

 ...like this as it emerges from its case. I have no idea how to identify the species at this stage.

A small, hairy fly with a tapering abdomen. It is a Dark-winged Flesh fly Nyctia halterata. A new species for my log though I suspect I have seen it previously and not identified it.

The mirid bug Deraeocoris flavilinea

 This is a pupa of a Harlequin Ladybird Harmonia axyridis

Pollen beetles Meligethes sp. having a good feed...

...while these two are having a good time.

My first Common Red Soldier Beetle Rhagonycha fulva of the year. In recent years it has acquired the vernacular name of Hogweed Bonking-beetle for obvious reasons. I will stick with the historic name.

(Ed Wilson)

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The Flash: 09:15 – 10:15

(140th visit of the year)

New bird species:
An addition to my 2026 bird species list from here. As I arrived there was much noise from the island, mostly Magpies and Carrion Crows also one or more Great Spotted Woodpeckers and, most unexpectedly a calling Tawny Owl. No doubt this had been found in its day-time roost and was being hounded. I did not see it break cover. Species #70 here this year.

Bird notes:
- *the Canada Goose gosling is still present.
- the lower number of geese is probably due to many having finished breakfast and moved inside the island out of sight.
- nine Mute Swans were noted. I presumed the pen is still on the nest.
- *the duck Mallard has lost one of her small ducklings.
- my later visit revealed seven broods of juvenile Coots with one of these being a new brood (and a second brood for the adults).
- two Great Crested Grebes seen keeping well apart.
- after the earlier kerfuffle on the island a Great Spotted Woodpecker was drumming at the South end. I am not sure I expected after a brood has flown. I don't believe this is species is double-brooded. Could it be there are two pairs in the area?

Bird(s) noted flying over here:
- 1 Jackdaw

Noted on / around the water:
- *88 + 1 (1 brood) Canada Geese
- 16 Greylag Geese
- 10 Mute Swans perhaps
- *16 (?♂) + 7 (1 brood) Mallard
- 5 (4♂) Tufted Duck
- 4 Moorhens
- 42 + 15 (7 broods) Coots
- 2 Great Crested Grebes
- 1 Lesser Black-backed Gull: adult, briefly

Hirundines etc. noted:

None

Warblers noted (the number in brackets refers to birds singing):
- 3 (3) Chiffchaffs
- 2 (2) Blackcaps again

Noted around the area:
The vegetation was still very wet during my visit. Only...

Beetles:
- Harlequin Ladybird Harmonia axyridis var. succinea

Not yet looking much like a Canada Goose. The sole surviving gosling of the year here.

Only seven Mallard ducklings remain. Someone lend their mother a handkerchief.

(Ed Wilson)

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2006
Priorslee Lake
Just a single cygnet left
(Martin Adlam)