12/07 Thatcham Marsh LNR

Location: Thatcham Marsh LNR CES Visit 2026.08

Session:     12/07/2026 06:00 to 11:00hrs

Present:      JHW, IW, JL.

Weather:    overcast early clear later, breezy, warm then hot.

Nets: 192M net along the reed bed ride (net1A & 2A) + 1 12M rides set in scrub (site B) up from 06:30 to 10:30hrs.

Lures:   (none)

                        

Robberfly probably Slender Footed or Awl species.

Notes: Fewer Reed Warblers than expected particularly juveniles. It seems there are fewer birds of all species on and around the reed bed this year. It will be interesting to see if the lower ringing totals for 2026 apply locally or nationally. We may get some idea of this over the remaining CES visits as many of the warbler species encountered then are stop-overs from elsewhere on their way south. Also of note is that the phragmites growth is especially vigerous, presumably due to the hot weather, and the adjacent reed is higher than the top of the misnets along the reed bed ride so some birds flying towards the scrub fly over and miss the nets.

    Recaptures: (08)

    Cettis Warbler ringed: 13/06/2026.

    Dunnock ringed: 02/08/2025, 04/07/2026.

    Reed Warbler ringed: 02/05/2026, 31/05/2026.

    Robin ringed: 04/07/02026.

    Wren ringed: 21/06/2026, 28/06/2026.

Sightings: Another quiet session - few birds scrub. Some small blue damselflies on the wing but never got round to a specific ID; probably Common or Azure or maybe both.

10/07 Greenham Common

Location: Greenham Common - Western Enclosure wk 2026 wk28-Fri

Session: 10/07/2026 07:40 to 10:30hrs

Present: IW, JL, KMB.

Weather: bright sunny, very hot, light breeze.

Nets: 48metres 3 Rides, up from 08:00 to 10:10 hrs closed early due to the heat.

Lures audio: (BC-CC-FC-GC-GW-WH-LW-WO),(W-WC-RT-SF-TP-YW),(GH),(RT), intermittently.

Notes: Not a bad morning by this year’s standards. The second Lesser Whitethroat of the year and a few more Blackcaps and Garden Warblers; the latter should start moving through back to winter quarters over the next two or three weeks; Blackcaps passage doesn't usually peak until late August. We stopped at around 10:00hrs as it started to get very hot, also the birds seen earlier flying about had disappeared, presumably retired to the shade.

Recaptures: (00)

 

Sightings: First a male Sparrowhawk seen flying SSW carrying prey, a little later a female was soaring near a Red Kite. Once it started getting very hot most birds disappeared presumably into cover. 

07/07 Greenham Common

 Location: Greenham Common - Western Enclosure wk 2026 wk28-Tue

Session: 07/07/2026 07:40 to 10:55hrs

Present: IW, JL.

Weather: bright sunny, hot, breezy.

Nets: 48metres 3 Rides, up from 08:00 to 10:30 hrs

Lures audio: (BC-CC-FC-GC-GW-WH-LW-WO),(W-WC-RT-SF-TP-YW),(GH),(RT), intermittently.

The first Lesser Whitethroat of 2026 here. After re-consulting the ID guide (Svensson) and checking the photos decided it to be an adult just starting its main moult. The deciding factor was the whitish eye crescent of the top portion of the iris just discernible in this photo. Juveniles birds have a plain brown iris and no crescent. 

Notes: The forecast was for the beginning of another extra hot period and so it was, particularly towards the end of the session. The capture was much as expected though we are usually getting a few Willow Warblers now; these are notably absent for the time of year including no singing males except on the first visit in week 25. Once it became uncomfortably hot, around 10:00hrs it was noticeable that bird activity over and about the site dropped.

Recaptures: (00)

Sightings: A family party of Stonechats were in the enclosure as we arrived to put the nets up. At least two Dartford Warbler active for much of the session including some song. IW spotted the Swifts high-up towards Newbury.

04/07 Thatcham Marsh LNR CES Visit 2026.07

Location: Thatcham Marsh LNR CES Visit 2026.07

Session:     04/07/2026 06:00 to 11:00hrs

Present:      IW, JHW, JL, KMB+1.

Weather:    overcast, breezy, warm.

Nets: 192M net along the reed bed ride (net lengths 1A & 2A) + 1 12M rides set in scrub (site B) up from 06:30 to 10:30hrs.

Lures:   (none) 

Although taken at different time of the year both the above photos are taken facing south from approximately the same spot. The left hand winter shot shows the area of reed bed then known as the triangle as it was in 1972. This was cleared in the late 1970s when the extensive reed beds south of the railway were excavated for gravel and to create the fishing pits – the reed bed was owned by the angling club. In the left hand photo the bridge was over the Moor Ditch stream. When access to the gravel now fishing pits was created the stream was blocked and diverted into an exisiting adjacent overflow colvert through the railway embankment, allowing the track to be created under the railway bridge giving access to the gravel workings now to the fishing pits. The small area of reed known as the triangle held wintering Bearded Tits each winter from 27th Feb 1971 to 6th Apr 1975; 96 birds were ringed or retrapped, most came from RSPB Minmere Nature Reserve near Saxmundam Suffolk. In the 1970 most of the immediate area was reed bed with some scrub, now much of the area is mature scrub with small areas of fragmented reed.

Notes: Comparison with last years matching CES visit 2025.07 starkly shows the apparent drop in Reed Warbler and Sedge Warbler numbers on the main reed bed something we have been aware for sometime. It would be nice to think that numbers will pickup over the next visit or two, hope so however there are few singing in the vacinity.

Recaptures: (14)

Cettis Warbler ringed: 12/07/2025, 13/06/2026, 21/06/2026x2.

Chiffchaff ringed: 12/07/2025.

Reed Warbler ringed: 11/05/2024x2, 10/05/2025, 31/05/2026, 21/06/2026x2, 28/06/2026

Wren ringed: 06/08/2023, 12/10/2025.

Sightings: Another quiet day bird-wise and the overcast conditions limited the number of insects on

the wing.

03/07 Greenham Common

Location: Greenham Common - Western Enclosure wk 2026 wk27-Fri

Session: 03/07/2026 07:40 to 10:50hrs

Present: IW, JL.

Weather: bright sunny, warm, light breeze.

Nets: 48metres 3 Rides, up from 08:00 to 10:30 hrs

Lures audio: (BC-CC-FC-GC-GW-WH-LW-WO),(W-WC-RT-SF-TP-YW),(GH),(RT), intermittently. 

The last bird of the session – a Chiffchaff juvenile - note the disseminated feathers. This individual was one of two birds with a fat score of B2, possibly indicating they are migrating, also there are signs that the feathers above the top mandible have some pollen stuck to them. This occurs if pollen sticks to the birds feathers when they are probing flowers for insect etc. It is most often noticable in spring when these feathers are sometimes heavily "caked" in pollen when they have been probing flowers on their way back from the Mediterranean and/or Africa.

Notes: A few Blackcap today, probably dispersing locals, most had no fat build-up, some had signs of fat beginning to build around the tracheal pit but not enough to score. One of the Chiffchaffs and a Blackcap had the base of their tracheal pits (throat) obscured by fat to about one third – colour Yellow-pink as opposed to dark red ; the first we’ve seen so far this year.

Recaptures: (00)

Sightings: The local family party of Dartford Warblers was active for a while in the nearby scrub sometimes following the Stonechats.