23 Jul 14

Priorslee Lake: 4:29am – 6:10am // 7:15am – 8:51am

14.5°C.> 23.0°C  Early low cloud took until 8:00am before changing to hazy sun: after 9:00am before the very moderate visibility significantly improved. Light E wind.

Highlight was the brief sighting of an unidentified small grebe sp. at the lake. The bird was seen in with a party of loafing Mallard in the middle of the lake at 4:45am. The characteristic shape was well seen and the size easy to judge. The bird was just a silhouette at that time from my position. By the time I had moved to a location from where I stood a chance of getting any plumage detail the bird had disappeared. The choice is between Horned (aka Slavonian) Grebe and Black-necked Grebe. In breeding plumage they should be separable in silhouette but I am unsure when they lose the breeding ‘tufts’: and anyway the bird was at least as likely a juvenile which would not be so easy. I would favour Black-necked but it cannot go in the log as anything other than “sp.”. It was certainly not a Little Grebe and all the resident juvenile Great Crested Grebes are significantly larger; as any fledged bird from elsewhere would be (with both species being County rarities I would have needed to get a full description anyway).

(82nd visit of the year)

Other notes
Great Crested Grebes back to normal strength this morning.
3 Tufted Duck flew through.
The male Sparrowhawk seen arriving at the calling juveniles (seemed to be only one bird today): was unable to see whether the adult was carrying prey.
More Moorhens but fewer Coots – the latter probably because of earlier count while some birds still in the reeds.
No Swifts this morning: I did wonder whether the early change in the weather might have encouraged them to leave but there were birds over Trench after it brightened up. After adult Cuckoo, Swift is the first species to leave us after breeding with the majority gone by very early August.
Another good count of Pied Wagtails over: 13, including a loose group of 8.
1 Common Whitethroat heard calling in same area as family party last seen / heard over a week ago.
Corvid roost dispersal again >30 minutes later than usual on dull morning.
2 large bats
1 ‘The Clay’ moth on a street lamp.
My first Brown Hawker of the year at this location: also another unidentified hawker, likely a Common Hawker.
1 carpet moth in the tunnel which was too worn to identify.

? Grebe – see highlight
2 + 3 (2 broods) Great Crested Grebes
2 Grey Herons
2 Swans
18 Greylag Geese: 17 outbound
Canada Geese heard only
29 (?) Mallard
3 Tufted Duck flew through
6 + 2 (2 broods) Moorhens
21 + 15 (5 broods) Coots
38 Black-headed Gulls arrived briefly
9 Lesser Black-backed and 1 Herring Gull over
8 (7) Song Thrushes
5 (1) Reed Warblers
1 (0) Whitethroat
9 (4) Blackcaps
4 (1) Chiffchaff
Corvid roost dispersal: 214 Jackdaws and 102 Rooks

This moth is called The Clay and is shown resting on one of the street lamps this morning.

This is not a moth but a caddis fly sp. – while some moths do have long antennae like this it is the shape of the wings at rest that separates caddis flies.

This grass moth is yet another Chrysoteuchia culmella (or Garden Grass-veneer): about the only grass moth evident at the moment, though hopefully that will change in a few days as several more marked species emerge.

This is a female Blue-tailed Damselfly. Note that on this, presumed fresh, individual there is only the merest hint of blue on the tail. Males are blue-tailed from the get-go, but females take some time and the blue is never so extensive or intense. Note also the strange glaucous effect on the central part of the body, apparently caused by the light passing through / reflected by the closed wings.

(Ed Wilson)


Priorslee Flash: 6:20am – 7:00am

(70th visit of the year)

Further reduction in geese numbers as birds are able to fly off.
Yesterday’s new brood of a single juvenile Coot not seen but weather still grey at that time and was possibly being brooded in the nest.
A caddis fly sp. was the only insect (other than spiders – yes I know they aren't insects) that were on the lamps here this morning.

2 + 1 Great Crested Grebes
2 Swans
39 Greylag Geese
1 Cackling Goose
127 + 1 Canada Geese
The all-white feral goose
21 (20) Mallard
1 all-white feral Mallard-type
11 (9) Tufted Ducks
2 + 3 (3 broods) Moorhens
9 + 10 (>4 broods) Coots
5 Black-headed Gulls
7 House Martins
1 (1) Song Thrush
2 (0) Blackcaps
2 (1) Chiffchaff

(Ed Wilson)


Trench Lock Pool: 9:00am – 9:55am // 10:36am – 10:40am

(31st visit of the year)

Same 3 broods of Canada Geese.
The 8 Tufted Ducks were new in here: all drakes.
At least 17 of the Coots are juveniles
A calling Bullfinch was a new species for me here this year.
Black-tailed Skimmer dragonfly was new for me here.

The counts
2 + 2 (1 brood) Great Crested Grebes
1 Grey Heron
2 Swans
2 Greylag Geese over
1 Greylag x Canada Goose
24 + 7 (3 broods) Canada Geese
21 (19) Mallard
2 feral Mallard
8 (8) Tufted Ducks
4 + 3 (2 broods) Moorhens
66 Coots
2 Black-headed Gulls: 1 over
5 Swifts
3 Swallows
8 House Martins
1 (1) Blackcap
1 (0) Chiffchaff

(Ed Wilson)


Trench Middle Pool: 10:00am – 10:32am

(16th visit of the year)

Fewer Greylag and many fewer Canada Geese today now they can fly: but not all the goslings seen last time would have fledged by now so assume that some were inside the island. Perhaps this was where the usual posse of feral ducks were hiding.
3 Swans again and still no rings read
2 Terrapin sp!
Green-veined White butterfly was new here this year for me.
Brown Hawker was also new here this year for me with another hawker sp. that was likely a Common Hawker but was unable to clinch the ID.
2 large Carp were seen clearly swimming just below the calm surface.

The counts
1 Great Crested Grebe
3 Swans
15 + 9 (? broods) Greylag Geese
24 + 0 Canada Geese
32 (27) Mallard
(no feral Mallard-type ducks)
10 (7) Tufted Duck
5 + 2 (2 broods) Moorhen
5 + 5 (2? broods) Coots
6 Black-headed Gulls: 5 over
1 Lesser Black-backed Gulls over
1 (0) Chiffchaff

This is the terrapin sp. at Middle Pool. No terrapins are native to the UK but are frequently seen where they have been discarded when they outgrow their ‘Terrapinarium’. It looks most like a Cumberland Slider (Trachemys scripta trootsii) though I read that in practice most terrapins sold in the UK are likely to be ‘mutts’ – hybrids of several species. Most species can live quite well outdoors in Britain and it has been known for them to lay eggs, but it is thought than none has ever hatched in the wild.

This might just buck the trend – there are two individuals here. 

(Ed Wilson)