24 May 22

Priorslee Lake and The Flash

9.0°C > 12.0°C: A mixed bag: started mostly cloudy at multiple levels; cleared sunny spells at 06:30 but by 07:30 cloudy with showers in the area; sunny again after 09:00. Brisk feeling W wind. Excellent visibility.

Sunrise: 05:00 BST

Priorslee Lake: 04:40 – 05:50 // 06:55 – 09:40

(120th visit of the year)

Generally a quieter morning with things recovering from an overnight soaking.

Bird notes:
- One of the Canada Geese goslings has perished since yesterday. I found its soggy and mangled body near the sailing club shelter. I could not tell how much of the injury was caused during its killing and how much was done later by e.g. crows, rats. Neither could I say whether it was the cob Mute Swan that had killed it or whether it had been attacked by, say, a fox.

Birds noted flying over here:
- 2 Greylag Goose: pair outbound
- 1 Stock Dove again
- 6 Wood Pigeons
- 1 Herring Gull
- 1 Lesser Black-backed Gull
- 1 Common Buzzard
- 6 Jackdaws

Hirundines etc. noted:
- c.40 Swifts
- 2 Sand Martins
- 4 Barn Swallows
- 4 House Martins

Warblers noted (figures in brackets relate to singing birds):
- 1 (1) Cetti's Warbler
- 11 (9) Chiffchaffs again
- 1 (1) Sedge Warbler
- 8 (8) Reed Warblers
- 16 (14) Blackcaps
- 3 (3) Garden Warblers
- 1 (1) Common Whitethroat

Counts from the lake area:
- 2 + 1 (1 brood) Canada Geese: see notes
- *2 + 8 (1 brood) Mute Swans
- 8 (6♂) Mallard
- 3 Moorhens again
- 22 + 13 (6 broods) Coots
- 5 Great Crested Grebes

Noted on / around the street lamp poles pre-dawn:
- *1 Pale Tussock moth (Calliteara pudibunda)

Noted later:

Moths:
- *Plum Tortrix (Hedya pruniana)
- Common Nettle-tap (Anthophila fabriciana)
- Silver-ground Carpet (Xanthorhoe montanata)
- *caterpillar of Drinker moth (Euthrix potatoria)

Bees, wasps, etc.
- Buff-tailed Bumblebee (Bombus terrestris)
- *Common Wasp (Paravespula vulgaris)
- *German Wasp (Vespula germanica)
- *possible Black-horned Clover-sawfly (Tenthredo brevicornis)
- *two different ichneumon sps.

Hoverflies:
- *Buttercup Blacklet (Cheilosia albitarsus) (also known as Late Buttercup Cheilosia)
- *Marmalade Hoverfly (Episyrphus balteatus)
- Chequered Hoverfly (Melanostoma scalare)

Damselflies:
- Blue-tailed Damselfly (Ischnura elegans)
- Azure Damselfly (Coenagrion puella)

Other flies:
- Greenbottle Lucilia sp.
- Scorpion Fly (Panorpa sp.)
- Yellow Dung Fly (Scathophaga stercoraria)

Beetles etc.:
- 7 Spot Ladybird (Coccinella 7-punctata)
- Harlequin Ladybird (Harmonia axyridis)
- Nettle Weevil (Phyllobius pomaceus)

Bugs:
- Red-and-Black Froghopper (Cercopis vulnerata)
- Common Green Shieldbug (Palomena prasina)

Other insects:
- Common European Earwig (Forficula dentata)

Slugs / snails:
- White-lipped Snail (Cepaea hortensis)

Spiders:
- Tetragnatha sp. stretch spider

New flowers for the year:
- *Ox-eye daisy (Leucanthemum vulgare)

I should note that the Giant Hogweed plants (Heracleum mantegazzianum) have been dealt with some days ago. This year the plants have been chopped off close to the ground and the stems remain accessible – should you wish to do so! It does not appear that the cut stems and foliage have been wrapped in thick plastic and just left somewhere - as they have been for the past two year where they remain.

The cob Mute Swan looking after his brood of eight cygnets. Mum was just out of the picture. Note that one cygnet seems to be slightly apart from the rest. This was true much of the time but whether it was the same individual every time I could not tell.

I wonder what the collective noun for cygnets is? A huddle? A cuddle?

And a short video of the cob reaching down to pluck weed from the bottom of the lake to feed to the hungry brood. One cygnet again slightly separate from the others.

This micro-moth is a Plum Tortrix (Hedya pruniana). It is a very common moth though it can be hard to spot as it disguises itself as a bird-dropping. I see it most year. This year it is moth species #27 here.

After one at The Flash yesterday (it was still there today) I found this Pale Tussock moth (Calliteara pudibunda) at the lake, tucked up underneath the horizontal lamp-head on one of the street lights. It is at least eight years since I last recorded this species here. This one seems to have even more 'fur' on its front legs.

Yet another apparent caterpillar Drinker moth (Euthrix potatoria). This is number six this year and as far as I can see from my logs I have just a single previous record of an adult from 2016.

This is a Common Wasp (Paravespula vulgaris). Note that the yellow marking along the side of the thorax is parallel-sided.

On this wasp the yellow marking along the side of the thorax does not look parallel-sided, suggesting this is a German Wasp (Vespula germanica). The abdomen pattern of these species is an unreliable guide and the other usual identification aid is to look at their faces. Easier said than done!

This is possibly a Black-horned Clover-sawfly (Tenthredo brevicornis). According to Stephen Falk's web-site the four Tenthredo species are hard to separate, not helped here by the wings masking the detail of the abdomen pattern. However his photos show several of them on buttercups so perhaps this is a good call.

One of two ichneumon species I saw today. It somewhat resembles Amblyteles armatorius though the leg markings are slightly different. So it will remain unidentified.

And the other ichneumon I found. About all I can add is that on this species the antennae are splayed whereas on the previous species they curved outwards.

This is probably the hoverfly Buttercup Blacklet (Cheilosia albitarsus) (also known as Late Buttercup Cheilosia). I cannot see enough of the front pairs of legs to check the markings to be certain.

Sitting nicely with wings akimbo to show the abdomen markings is this Marmalade Hoverfly (Episyrphus balteatus).

A Leopard cannot change its spots but a Harlequin Ladybird (Harmonia axyridis) can make them fade away.

I first noted new flowers of this Common Hogweed (Heracleum sphondylium) a few days ago but promptly forgot to photograph it. Note the dense cluster of flowers in each umbel and also how the petals of the outermost flowers are enlarged. This plant will be seen in flower from now until well after the end of the year though from October onwards the flowers look rather sad and I doubt there are any insects to pollinate them.

The Ox-eye daisies (Leucanthemum vulgare) have just begun to flower.

(Ed Wilson)

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The Flash: 05:55 – 06:50

(117th visit of the year)

As happens most years around this time a significant growth of weed is appearing on the water surface, especially along the E side.

Bird notes:
- I am not sure what Canada Goose goslings I saw yesterday. Today there was one well-grown gosling and its parent together with six smaller goslings and their parents on the bank all trying to keep the adult Mute Swan at bay. I helped but I suspect it returned as soon as I moved off. Later a pair of adults with one small gosling paddled across the water.
- A new brood of eight Mallard ducklings/
- Only one juvenile Moorhen seen again: perhaps there is only one extant.
- Fewer juvenile Coots seen. I only noted two from the usual brood of four and their parents were busily engaged in nest-enlargement, as they are wont to. Another brood of two juveniles by the island was a new location for my log this year.

Birds noted flying over here:
- 1 Lesser Black-backed Gull again
- 1 Jackdaw

Hirundines etc. noted:
- 6 Swifts
- 2 House Martins

Warblers noted (figures in brackets relate to singing birds):
- 4 (4) Chiffchaffs
- 4 (4) Blackcaps

Noted on / around the water:
- 53 + 8 (3 broods) Canada Geese
- 2 Greylag Geese
- 3 Mute Swans
- *17 (15♂) + 8 (1 brood) Mallard
- 1 (1♂) all-white duck (Aylesbury Duck)
- 4 (3♂) Tufted Duck
- 5 + 1 (1 brood) Moorhens
- 21 + 4 (2 broods) Coots
- 2 Great Crested Grebes

Noted on / around the street lamp poles:
- 1 Pale Tussock moth (Calliteara pudibunda): same position as yesterday despite all the rain.
- 2 Grouse Wing caddis flies (Mystacides longicornis)

Noted elsewhere:
- *newly identified flower – Borage (Borago officinalis)

A grab-shot as the duck Mallard and eight ducklings briefly emerged from the waterside vegetation. But will any survive?

The best I could do in a gloomy squirrel alley. I think this flower is Borage (Borago officinalis). Not too sure what it is doing here, perhaps a garden escape.

(Ed Wilson)

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Between the lake and The Flash:

- No Mallard today
- Moorhens heard calling at the both pools again
- No warblers seen or heard during either transit.

(Ed Wilson)

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In the Priorslee Avenue tunnel:

- very few midges

(Ed Wilson)

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On this day can be found via the yearly links in the right-hand column.

Sightings from previous years without links are below

2007

Priorslee Lake

Cuckoo

(Ed Wilson)