Wilstone Reservoir CES 2020 summary

The 2020 CES season should have been from the 30th April until the 2nd of September. However, due to imposed Covid restrictions the first visit was actually on the 14th June. 

The birds per session figure was 82.25 calculated by dividing the total of each session's catch by the number of visits,8. This figure compares to 85.75 from 2019 and 67.0 in 2018. 

During 2020 there was a distinct lack of juveniles of resident species. Migrant species juveniles were near or slightly better than in normal years. Blackcap were down after the exceptional influx of numbers during August of last year. Reed Warblers suffered from the reedbed water level being low throughout the summer, affecting nesting and feeding opportunities resulting in a lower than average catch.

In summary, 2020 CES shows it to have been an average year.

Johne Taylor

	Adult	Juvenile	Total
Blackbird	6	1	7
Blackcap	30	87	107
Blue Tit	8	13	21
Cettis Warbler	0	2	2
Chiffchaff	10	70	80
Dunnock	1	0	1
Garden Warbler	2	2	4
Goldcrest	0	1	1
Goldfinch	1	0	1
Great Tit	3	10	13
Long Tailed Tit	0	24	24
Marsh Tit	0	2	2
Reed Bunting	6	0	6
Reed Warbler	77	89	166
Robin	4	20	24
Sedge Warbler	10	70	80
Song Thrush	10	1	11
Treecreeper	0	2	2
Whitethroat	0	2	2
Willow Warbler	1	21	22
Wood Pigeon	1	0	1
Wren	4	23	27
Total	181	401	582

Marsworth, Autumn is upon us.

After a week of wind and rain we grabbed the chance to go out on Wednesday even though it still looked fairly breezy. We put up a few nets in the more sheltered eastern corner of the site and a new net between some hazel trees. I had planned to fill the time with some scrub clearing but it was a busier morning that expected with that interesting mix of the last summer migrants and autumn visitors. We started with Chiffchaffs and Blackcaps and then a flurry of Goldcrests came to the tape lure along with four Bullfinch.

The new net was a success and caught four Lesser Redpoll, a new species for Claire, plus a Chaffinch. The Chaffinch was a young male that had unusually moulted all the secondaries and a couple of primaries on one wing Given the terrible condition of the feathers on the other wing it was likely that he had had to replace similarly damaged feathers. 

Juvenile Chaffinch with new secondaries on right wing compared with tatty feathers on left wing.

All the Redpolls were juveniles, aged according to the shape of the tail feathers and a moult limit along the greater coverts. None were showing any red feathers on the breast so we could not sex them.

Redpoll wing showing 6 old greater coverts

Lesser Redpoll

The last bird of the day was a new Great Spotted Woodpecker which was still moulting its primaries as part of its post juvenile moult. The contrast between the black lesser coverts and the duller greater coverts plus the good condition of the unmoulted outer primary, aged the bird as a juvenile. Its body moult was nearly complete and there were just a few little red feathers left in the crown but the new bright red nape patch means this is a male.

Greater Spotted Woodpecker wing. 

The bright red nape of a male Greater Spotted Woodpecker with just a few red juvenile feather left in the crown.

We finished with 56 birds (11 retraps/45 new)

Bulbous Honey Fungus on dead willow