26/07 Thatcham Marsh LNR CES visit 2025.09.

Location: Thatcham Marsh LNR CES Visit 2025.09

Session: 26/07/2025 06:00 to 11:10hrs.

Present: JHW,IW,JL,IQ.

Weather: sunny, clear, bright, warm, calm.

Nets: one 198M long reed bed ride plus 12m scrub ride additional net up from 06:30 to 10:30hrs.

Lures (): None

One of two Sedge Warblers caught today this one is the adult re-trapped today.

Notes: We couldn’t ring for visit 9 at the first opportunity (last Sunday 20th). Rain was forecast so we postponed until this week – there were several showers that morning. The 33 total for visit 9 is below the average of 46 (range 2019-20 and 1998-87). It is noticeable that the higher totals for most visits are for the earlier years of the CES (started 1993). There is a definite drop in Reed Warbler numbers. For visit 9 in 1998 - 50 were processed whereas in 2019 – 8 processed. This visit CES 2025.09 12 processed. Reed Warbler distribution is patchy along the ride; they once appeared to be distributed throughout the 198metre + length. Possibly the reed cut and electricity work of winter 2024/25 had some affects but most recent winters the reeds have not been cut but still Reed Warbler numbers have dropped. The Sedge Warbler situation is less clear as numbers are lower so the change is not as significant. Nationally we are told that the Sedge Warbler UK population is moving north due to global warming. The reed bed perimeter scrub is more mature than it once was to the point where some could be described as woodland so this is also affecting the type of birds.

FG =age indeterminate

Recaptures: (11)

Blue Tit               ringed: 21/06/2025.

Cetti’s Warbler   ringed: 06/10/2024.

Chiffchaff            ringed: 08/05/2022.

Long-tailed Tit    ringed: 24/04/2022.

Reed Warbler    ringed: 11/06/2023, 05/04/2024, 03/05/2024.

Sedge Warbler  ringed: 29/06/2025

Treecreeper       ringed: 13/04/2025

Wren                  ringed: 12/07/2025x2.

Sightings: Tufted Duck totals mostly ducklings, Swifts, Swallows and House Martins were high

up so there were probably more unseen. Water Rail calling near each end of ride. Great Spotted

Woodpecker quite vocal for a while probably a family party moving through. Bullfinch were calling for

most of the morning, also calling yesterday on a check out visit, about the only bird I notice then. A

Muntjac ran along in front of me when checking the nets fortunately it turned into the reeds and not

the nets!