6 Sep 14

Priorslee Lake: 5:44am - 8:42am

14.5°C > 15.0°C: low overcast, broke for a while c.7:30am but returned. Light NNW wind. Moderate visibility.

Highlights this morning were:
- Black Tern hawking over the lake from before 6:00am until 6:40am when it disappeared. My first this year. Sadly left before light-enough to even try for a record shot.
- a Willow Warbler briefly singing and then seen alongside the school construction work in Teece Drive. My latest-ever record at the lake.

Migrants noted were
- a single Barn Swallow very high up heading S – only found because it flew through my bins while I was checking passing large Gulls.
- 3 House Martins also high overhead and located only after they called.
- party of 8 Meadow Pipits fling SE.

(97th visit of the year)

Other notes:
Geese again on flight lines in far distance and also while I was trying to ID the tern in the pre-dawn poor light, so likely to be under-recorded.
4 Mallard only.
8 Tufted Duck seen in flight circling low to the N but seemed not to be leaving and certainly did not arrive.
Unusually c.180 Black-headed Gulls arrived low and fast from the S (rather than from Ricoh)
Many large gulls with them and more before and after: hard to count as birds circled, arrived, left, returned or flew directly over.
1 Reed Warbler heard – different location to recent sightings.
Minimal corvid passage again: but 4 more Jackdaws much later flying E.
2 large Noctule-type bats
1 wasp sp. the only insect on the lamps

2 + 3 Great Crested Grebes
2 Grey Herons
2 Swans
4 Greylag Geese (all outbound)
53 Canada Geese (all outbound)
11 (?) Mallard
8 (?) Tufted Duck over
4 + 6 (4 broods) Moorhen
77 Coots
c.200 Black-headed Gulls
c.160 large gulls (c.50 of these over): 2 of these at least Herring Gulls
1 (0) Reed Warblers
1 (0) Blackcaps
10 (3) Chiffchaffs
1 (1) Willow Warbler
Corvid roost dispersal: just 2 Jackdaws and 9 Rooks logged

Always shy: a Jay lurking in the tree-tops.

An adult Lesser Black-backed Gull. Note that this bird has yet to complete its wing-moult with some white areas where some of the new coverts have yet to grow and cover the pale bases of both the primaries and secondaries. Also the pattern of the wing-tip white ‘mirror’ is very different and only shows on the outermost primary. Note also a dusting of dark marks on the head – in full winter plumage these will become extensive and much darker.

A noisy dispute between these two juvenile / 1st winter Lesser Black-backed Gulls. All the other birds are also Lesser Black-backed Gulls: one adult and all the rest juvenile / 1st winters.

Its not carrying a fish but as this juvenile / 1st winter Lesser Black-backed Gull struggles in to the air the spread wing is well shown. It appears that P6 (the fifth primary from the outside) is missing from both wings. On the left wing there do seem to be only nine primaries – there should be ten. Harder to see where the primaries end and the secondaries start on the right wing.

Compare with the full wings shown by the bird on the left. That bird seems to have tatty secondaries.

But look: it must have been an effect of the effort to get airborne as here all ten primaries are clearly present. And just look at the way the primaries separate under the strain as the left-hand manoeuvres to try and reach whatever the first bird is carrying.

(Ed Wilson)