30 Jul 19

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

Priorslee Lake:  04:15 – 06:00 // 06:55 – 07:05 // 08:55 – 10:05
The Flash:  06:05 – 06:50
Trench Lock Pool:  07:15 – 07:25 // 08:05 – 08:45
Trench Middle Pool:  07:30 – 08:00

14.0°C > 19.0°C:  Clearing for a while after heavy overnight rain. Clouding again later. Light mainly E wind. Very good visibility.

Sunrise: 05:24 BST

Another early visit to Trench with split visits to the lake.

Priorslee Lake:  04:15 – 06:00 // 06:55 – 07:05 // 08:55 – 10:05

(186th visit of the year)

Two highlights from here
- At 04:35 I heard a tern calling – a so-called ‘Comic’ Tern (an Arctic or Common Tern): I do not have enough experience to reliably separate these birds on call alone. Soon afterwards I saw the bird sitting on a buoy. It was much too dark to identify which species it was. Within a few minutes the first Black-headed Gulls arrived to fight over who was going to sit on which buoy and the tern was displaced. Although I saw it briefly in flight thereafter it will have to go down as unidentified.
- Then at 04:45 I heard the call notes of a Greenshank and then briefly saw it in silhouette only. There is no mud to attract waders and it soon flew on. Bird species #95 for here in 2019. My first here since 24 August 2016.

Other bird notes from today
- One of the cygnets seems to spend a lot of time somewhat on its own. It does join the others at other times.
- 18 of the Black-headed Gulls were, unusually, on the football field at 05:50
- A group of 16 Barn Swallows flew S at 09:20. They must have checked the weather forecast and decided to head off for the winter. Seems really early for this species to be migrating.
- Very low number of corvids passing early again.

Bird totals:

Birds noted flying over or flying near the lake:
- 24 Canada Geese (4 groups outbound)
- 1 Lesser Black-backed Gull
- 4 Feral Pigeons
- 73 Wood Pigeons
- 10 Jackdaws
- 6 Rooks

Hirundines etc. noted:
- 16 Barn Swallows
- >8 House Martins

Warblers noted (singing birds):
**NB: I did not do my usual two complete circuits and not too much significance should be attached to these lower numbers**
- 8 (2) Chiffchaffs
- 2 (0) Blackcaps
- 4 (1) Reed Warblers

Counts from the lake area:
- 2 + 6 (1 brood) Mute Swans
- 2 Greylag Geese (arrived)
- 13 Canada Geese (3 throughout; 10 arrived)
- 13 (10♂) Mallard
- 1 Cormorant again: for a while
- 3 Grey Herons again: flew off later
- 6 + 3 (2 broods) Great Crested Grebes
- 7 Moorhens (1 adult; 4 juveniles; 2 undefined)
- 63 adult and juvenile Coots: the 2 small juveniles from the newest brood not seen
- 1 Common Sandpiper again
- 1 Greenshank passing
- 1 unidentified tern sp.
- 27 Black-headed Gulls

On the very wet lamp poles pre-dawn:
- 1 Common Plume (Emmelina monodactyla)
- 1 wasp (Vespa sp.)

The following logged later:
- No butterflies
- Moths (in species order):
- 1 Dingy Footman (Eilema griseola)
- Damselflies etc. (alphabetic order of vernacular name):
- Blue-tailed Damselflies
- Common Blue Damselflies
- Hoverflies:
- Only Marmalade hoverfly (Episyrphus balteatus) noted
And other things:
- 1 Grey Squirrel

It was pounding with rain at 03:45. By 05:15 the rain clouds were clearing away ....

... with almost calm conditions producing a great reflection.

When the sun did rise it shone through the clouds to give this effect

For cloud fans – I was attracted to this shape.

This is a Common Plume moth (Emmelina monodactyla). Looking at it under the LED street lights I assumed it was a White Plume (Pterophorus pentadactyla) and the first photo I took seemed to confirm that. The ‘flash’ was so harsh that I decided to take another from an oblique angle – hence this. That showed that it was not ‘white’ and was in fact a Common Plume moth. As a result I think I have to change the three I logged as White Plume moths yesterday: I was aware that it was a rather late date for that species to be flying.

I did a double-take at this, assuming it was a seed or seed pod on the leaf. Only when I looked more closely and could see legs did I realise it was a Dingy Footman moth (Eilema griseola). This view shows the relatively broad wing and the tapering yellowish edging.

This view is perhaps a better view of the moth but you cannot see the edging so clearly. Note the right wing is folded over the left wing. Different species seem to vary the order in which they fold their wings. I have never been able to ascertain whether any one species consistently folds the wings left or right – indeed whether an individual moth is consistent.

(Ed Wilson)

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The Flash:  06:05 – 06:50

(179th visit of the year)

Two highlights here as well
- At 06:15 I heard a flight call that I recognised but could not immediately put a name to. Luckily I located the bird concerned and its bulk triggered the memory bank – a Common Crossbill! My first-ever at this location and bird species #77 for me here in 2019.
- Later at 06:45 while checking the Tufted Ducks and attempting to sex them a small duck flew round. Assuming it to be another Tufted Duck repositioning I nevertheless checked it – a Teal. Either an eclipse drake or a duck. The bird pitched in to the water, stayed about 30 seconds and then left to the W. This species is usually the first duck species to return post-breeding: this seems unusually early.

Other notes from here:
- Just two Mute Swan cygnets seen. I was told there were only two yesterday evening. So was the bird seen dead on the island the third? Or the fourth that was recently returned from care after getting snagged on a fishing-hook? And anyway where is the other missing bird? (and where were they yesterday morning anyway?)
- Only one adult with one juvenile Great Crested Grebe noted. I am sure the others were somewhere – they have recently often been separated.
- Two Stock Doves seen flying in to trees around The Priorslee pub.
- The singing Chiffchaff was a most erratic songster. A juvenile trying its voice?
and, all moths on lamp poles
- 1 possible Golden-brown Tubic (Crassa unitella)
- 2 Garden Grass-veneer (Chrysoteuchia culmella)
- 1 Straw Grass-veneer (Agriphila straminella)
- 1 probable Common Grey (Scoparia ambigualis)

Birds noted flying over / near The Flash:
- 1 Feral Pigeon
- 8 Wood Pigeons
- 1 Crossbill (as highlighted)

Hirundines etc. noted:
- 3 House Martins

Warblers noted (singing birds):
- 3 (1) Chiffchaffs

Counts from the water:
- 3 + 2 Mute Swans
- 19 Greylag Geese
- 26 Canada Geese
- 1 (?) Teal, briefly
- 28 (>13♂) Mallard
- 16 (9♂) Tufted Ducks
- 1 + 1 (1 brood) Great Crested Grebes
- 4 + 2 (2 broods)  Moorhens
- 18 +3 (2 broods) Coots
- 5 Black-headed Gulls again: no juveniles

These birds always favour the darker areas, especially along the E side areas beside the two footbridges. An adult Moorhen with a begging juvenile. A second-brood bird: first-brood birds are now full-size and separable by their paler plumage.

A close-up of the juvenile. Note the bad across the bill, never shown by juvenile Coots.

Not positive about this. At the time I thought ‘caddis fly’ from the way the wings are held ‘roof-wise’. Looking at the photo of this critter which was 10 feet up a lamp-pole I was less sure. The colours revealed do not fit with caddis-flies which are basically brown. I suspect it is a Golden-brown Tubic moth (Crassa unitella), a species I have not seen before. It is very widespread and common and like most micro-moths easy to overlook and hard to identify.

A rather worn Garden Grass-veneer (Chrysoteuchia culmella). We can just see the gold tip to the wings and the angled marks near the wing tip.

The dark sub-terminal marks suggest this is a Straw Grass-veneer (Agriphila straminella).

One of those difficult ‘greys’. I am fairly certain that this is a Common Grey (Scoparia ambigualis). The width of the wing relative to the body eliminates most of the other species.

(Ed Wilson)

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Between the lake and The Flash:

- 1 Blackcap calling at the lower pool again
and
- 1 Harlequin Ladybird (Harmonia axyridis) on a lamp pole.

(Ed Wilson)

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Trench Lock Pool:  07:15 – 07:25 // 08:05 – 08:45

(36th visit of the year)

Notes from here:
- The Mute Swans now have a single cygnet. When I arrived all three were together. Later they were all scattered over the water. It strikes me that the cygnet is still too small to be left alone.
- The lone juvenile Great Crested Grebe still thriving. A pair feeding possibly three small juveniles – still on the parent’s back.
- Two of the Black-headed Gulls were juveniles with one of these sitting on rocks and very reluctant to move.
- After several blank visits warblers calling again with one Chiffchaff singing.
- Two Grey Wagtails
also
- 1 Speckled Wood butterfly (Pararge aegeria).
- at least 10 Peacock butterflies (Aglais io) flushed from ground, mainly along N side

Birds noted flying over / near here [other than local Wood Pigeons and Jackdaws]:
- 17 Canada Geese

Hirundines etc. noted:
- 5 Swifts

Warblers noted (singing birds):
- 3 (1) Chiffchaffs
- 1 Blackcap

Counts from the water:
- 2 + 1 Mute Swans
- 12 Canada Geese
- 17 (15♂) Mallard
- Feral Mallard not seen again
- 2 + 4? (2 broods) Great Crested Grebes
- 1 Moorhen again
- 14 adult and juvenile Coots only
- 7 Black-headed Gulls: 2 of these juveniles
- 4 Lesser Black-backed Gulls

At least the juvenile Great Crested Grebes are more or less balanced on their parent’s back!

This is the long-term juvenile Great Crested Grebe which has been looking after itself – successfully – for weeks. The adult plumes are just about starting to show.

Not sure this juvenile Black-headed Gull was too well. It seemed rather lethargic and, as notable here, the throat area seemed rather scruffy as if it might be damaged.

Usually this juvenile plumage is very short-lived. 

As it staggered across the rocks it spread its wings to allow us to see the plumage detail.

‘Little and large’. Wood Pigeon and Goldfinch share the cross-piece of a street lamp. 

(Ed Wilson)

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Trench Middle Pool:  07:30 – 08:00

(36th visit of the year)

A sign notes that work commences on the N-side embankment for at least two weeks starting next Monday (5th August) with the footpath redirected around the S side Mondays – Fridays.

With most of the geese now flying it is probably time to revert to later visits when the geese have returned from the fields and the gulls are in looking to be fed.

Other notes from here:
- No sign of the erstwhile surviving first brood Great Crested Grebe juvenile: I would have thought it too young to have fledged. Pair of adults seen with at least three very new juveniles.
- The second adult Great Crested Grebe not seen today either. The juvenile managing on its won.
- What sounded like a begging juvenile Common Buzzard from the trees to the S.
- A Tree Creeper was my first of the year here: bird species #50.
- Warblers – all Chiffchaffs – now calling again here as well as at Trench Lock.
- 1 juvenile Grey Wagtail flew in.
and
- 2 Terrapin sp. (probably Yellow-bellied Slider). Their previous basking spot fell in the water last year and this is my first sighting since

Birds noted flying over / near here.
None

Hirundines etc. noted.
None

Warblers noted (singing birds):
- 3 (0) Chiffchaffs

Counts from the water:
- 2 Mute Swans
- 22 + 1 (1 brood) Greylag Geese
- 29 Canada Geese: no juveniles identifiable
- 20 (?♂) Mallard
- 14 (10♂) Tufted Duck
- 2 + 3 (1 brood) Great Crested Grebes (see notes)
- 3 Moorhens only
- 25 adult and juvenile Coots
- 1 Black-headed Gull

(Ed Wilson)

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

2017
Priorslee Lake
Today's Report Here

2014
Local area
Today's News Here

2006
Priorslee Lake
13 Swifts
(Ed Wilson)