8 Jul 19

Priorslee Lake, The Flash, Trench Lock Pool and Trench Middle Pool

Priorslee Lake:  04:10 – 05:30 // 06:30 – 06:40 // 08:35 – 10:00
The Flash:  05:35 – 06:25
Trench Lock Pool:  06:50 – 07:00 // 07:50 – 08:25
Trench Middle Pool:  07:05 – 07:45

10.0°C > 17.0°C:  Areas of high cloud clearing somewhat. Then medium-level cloud after 09:15. Light SE breeze after calm start. Very good visibility

Sunrise: 04:55 BST

My now customary summer early visit to Trench with split visits to the lake.

Priorslee Lake:  04:10 – 05:30 // 06:30 – 06:40 // 08:35 – 10:00

(170th visit of the year)

Bird notes from today
- A pair of Little Grebes with two juveniles seen in the NE area. Bird(s) later heard calling from the NW area again
- Only one of the hitherto duo of well-grown juvenile Great Crested Grebes located. A seventh adult present, causing some commotion at times.
- The Common Tern arrived after 09:00 and had gone by 10:00.
- Three Black-headed Gulls present pre-dawn. These, or others, present on and off later with a certain new arrival of a newly-fledged bird.
- The corvids went out ‘the wrong way around’ this morning with the first party of 47 Rooks at 04:35 well ahead of the first party of 20 Jackdaws at 04:55. More sizeable groups of Rooks followed.
- 14 House Martins high over the estate / football field at 05:25. None seen or heard later.
- Two Sedge Warblers heard singing together with what seemed to be a third in rather spluttering song at the same time. None seen. Could these have included juveniles learning to sing?
- Song, in general, might be winding down now but no-one has told the Song Thrushes with nine birds singing lustily this morning.

Bird totals:

Birds noted flying over or flying near the lake:
- 2 Cormorants
- 16 Wood Pigeons
- 30 Jackdaws
- 123 Rooks

Hirundines etc. noted:
- 12 Swifts
- 14 House Martins

Warblers noted (singing birds):
- 8 (4) Chiffchaffs
- 13 (10) Blackcaps
- 1 (1) Garden Warbler
- 1 (1) (Common) Whitethroat
- 3 (3) Sedge Warblers (see notes)
- 5 (3) Reed Warblers again

Counts from the lake area:
- 2 + 6 (1 brood) Mute Swans
- 16 (14♂) + 1 (1 brood) Mallard
- 2 (1♂) Tufted Ducks: left
- 2 + 2 (1 brood) Little Grebes: other(s)? heard
- 7 + 2 (2 broods) Great Crested Grebes
- 1 Moorhen
- 26 + 27 (? broods) Coots
- 1 Common Tern
- 4 Black-headed Gulls (1 juvenile)

On the lamp poles pre-dawn:
- 1 Garden Grass-veneer (Chrysoteuchia culmella)
- 1 Inlaid Grass-veneer moth (Crambus pascuella)

Seen later:
Not warm-enough and not sunny-enough to tempt too many insects to fly. The following logged
- Butterflies (in species order):
- >20 Ringlets (Aphantopus hyperantus)
- Moths (in species order):
- several Garden Grass-veneers (Chrysoteuchia culmella)
- Damselflies etc. (alphabetic order of vernacular name):
- Blue-tailed Damselfly
- Common Blue Damselfly
also
- yet another unidentified dragonfly sp. flushed
- Hoverflies (alphabetic order of scientific name):
- very many Marmalade hoverflies (Episyrphus balteatus)
- >2 Common Drone-flies (Eristalis tenax)
- many Chequered Hoverfly (Melanostoma scalare)
- many Syrphus sp. hoverflies
- >5 Pellucid Flies (Volucella pellucens)
And other things:
- >10 pupa of Harlequin Ladybirds (Harmonia axyridis)
- 1 Common Red Soldier Beetle / Hogweed Bonking-beetle (Rhagonycha fulva)
- 1 Blue Mason Bee (Osmia caerulescens)
- 1 Honey Bee (Apis mellifera)

This is a new moth for the year here (#42) and another of those confusing ‘grass moths’. Despite the distinctive pale streak that alone is insufficient to identify it and we need the detail of the wing-edging as well to confirm it as an Inlaid Grass-veneer (Crambus pascuella)

A humble Honey Bee (Apis mellifera) only included to show the huge (relatively) pollen sac. When it was in flight this was what was most evident. Here on Common Hogweed (Heracleum sphondylium).

This attractive insect seems to be a female Blue Mason Bee (Osmia caerulescens). Not seen anything like this before.

This used to be known as Common Red Soldier Beetle (Rhagonycha fulva) but, surprisingly in these PC times, it seems to have acquired the vernacular name of Hogweed Bonking-beetle

(Ed Wilson)

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The Flash:  05:35 – 06:25

(163rd visit of the year)

Biggest surprise today was finding two Pochard amongst the group of Tufted Duck. One was certainly a drake: the other seemed to be a fledged juvenile. Most birds of this declining species leave for the summer and usually return to Priorslee in October. It does however breed in very small numbers within 15 miles of here. So far as I can check I have no previous logs at Priorslee between May and October.

Other notes from here:
- Probably overlooked was the Canada x Greylag Goose.
- Many Mallard out on the water. Could not locate any obvious immatures.

and
- on the still lit signpost to ‘The Priorslee’:
- 1 Garden Grass-veneer (Chrysoteuchia culmella) moth
- 1 Inlaid Grass-veneer (Crambus pascuella) moth
- 1 Riband Wave (Idaea aversata) moth
- 2 harvestman sp., probably Leiobunum rotundum

Birds noted flying over / near The Flash:
- 1 Feral Pigeon

Hirundines etc. noted:
- 1 Swift
- 1 House Martin (heard only)

Warblers noted (singing birds):
- 2 (2) Chiffchaffs
- 3 (2) Blackcaps

Counts from the water:
- 3 + 4 Mute Swans still
- 69 Greylag Geese
- no Greylag x Canada Goose noted
- 156 Canada Geese
- 44 (17♂) Mallard
- 2 (1) Pochard
- 18 (17♂) Tufted Ducks
- 2 Grey Heron: both flew off
- 2 + 2 (1 brood) Great Crested Grebes
- 3 + 1 (1 brood) Moorhens
- 17 + 7 (3 broods) Coots

Although out of breeding plumage this drake Pochard, with its red eye, is still relatively easy to identify.

The other bird, here with a drake Tufted Duck, is less easy. Note the reddish-brown body and the obvious eye-ring.

Here it is almost smiling at the camera! Checking the literature this seems not to be a moulting duck as I thought – that should not be so brown, there should be no pale on the throat and there should be a thin white line extending behind the eye. This suggests that this is a fledged juvenile.

Someone had left the lights on for ‘The Priorslee’ and on the ‘Pedestrian Entrance’ sign I found several moths including this one. This, like the one at the lake, is an Inlaid Grass-veneer (Crambus pascuella). A new moth for me here.

Also there was this rather pale moth with the four dots in its wings unusually prominent. Nevertheless the kink in the outer edge of the outer cross-line confirms this is ‘just’ a Riband Wave (Idaea aversata).

Still rather early in the year for harvestmen. These seem to be the common species Leiobunum rotundum. Note the second pair of legs is very long.

(Ed Wilson)

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Between the lake and The Flash:

- Adult Moorhen with juvenile at the lower pool
and
- 2 Common Grey moths (Scoparia ambigualis) on lamp poles
- 1 probable Base-lined Grey moth (Scoparia basistrigalis) on a lamp pole
- another moth on the wall of the Priorslee Tunnel – a Mottled Beauty (Alcis repandata)

This ‘grey’ moth looked rather different – much more cleanly marked, though that might mean no more than it being freshly emerged. Checking the literature the marking, especially the checkered wing-tips, more closely match the Base-lined Grey moth (Scoparia basistrigalis), though in the absence of genitalia examination it will have to remain a ‘probable’ ID.

On the wall of the tunnel under Priorslee Avenue I found yet another resting moth. This is a Mottled Beauty (Alcis repandata)

(Ed Wilson)

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Trench Lock Pool:  06:50 – 07:00 // 07:50 – 08:25

(33rd visit of the year)

Notes from here:
- Only two Mute Swan cygnets survive. One very recently dead cygnet along the unofficial footpath along the E side of the pool.
- Mallard numbers usually increase at this time of year. A good count today. Not able to sex all of them: predominantly drakes.
- The lone juvenile Great Crested Grebe continues to thrive, apparently unaided.
- Many more juvenile Coots evident today.
- 1 Grey Wagtail again.

Birds noted flying over / near here [other than local Wood Pigeons and Jackdaws]:
- 3 Black-headed Gulls
- 1 Lesser Black-backed Gull
- 15 Starlings

Hirundines etc. noted:
- 2 Swifts again

Warblers noted (singing birds):
- 2 (0) Blackcaps

Counts from the water:
- 2 + 2 Mute Swans (see notes)
- 8 + 6 (1 brood) Canada Geese
- 31 (?♂) Mallard
- 1 (1♂) Feral Mallard
- 2 + 1 (1 brood) Great Crested Grebes
- 1 Moorhen
- 17 + 10 (4 broods) Coots
- 1 Black-headed Gull
- 1 Lesser Black-backed Gull, briefly
- 1 Herring Gull, briefly

(Ed Wilson)

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Trench Middle Pool:  07:05 – 07:45

(33rd visit of the year)

Other notes from here:
- Most of the goslings almost indistinguishable from adults now.
- The all-white goose present again – or is it a feral duck?
- A Grey Wagtail yet again.
and
- 1 Common Grey moth (Scoparia ambigualis) on a lamp pole

Birds noted flying over / near here:
- 1 Lesser Black-backed Gull
- >40 Racing Pigeons

Hirundines etc. noted.
None

Warblers noted (singing birds):
- 4 (1) Blackcaps

Counts from the water:
- 2 Mute Swans again
- 122 + 7 (3? broods) Greylag Geese
- 110 + 4 (1 brood) Canada Geese
- 1 all-white ‘Greylag’-type goose (duck?)
- 17 (15♂) Mallard
- 5 (5♂) Tufted Duck
- 2 + 1 (1 brood) Great Crested Grebes again
- 4 + 5 (2 broods) Moorhens
- 13 + 16 (? broods) Coots

On one of the lamp poles I found yet another ‘grey’ moth. This seems to be a Common Grey (Scoparia ambigualis) – my first here

(Ed Wilson)

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On this day..........

2014
Priorslee Lake
Today's Sightings Here

2007
Priorslee Lake
A pair of Siskins close to the lake
(Martin Adlam)