CES Update, a trip to Skokholm and rooftop Gulling

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A busy couple of weeks for the Group, despite mixed weather.

Constant Effort Sites (CESs)

We reached half time at both our standard CES site at WWT Llanelli (now in its 20th year), and our more recently-established garden CES site at Crynant in the Dulais Valley, with six of twelve visits completed at both.

Llanelli CES

At WWT the surprise bird during visit 6 was a juvenile Willow tit. This species has been recorded before on the site, albeit none were noted during the breeding bird surveys carried out this year by staff.

The following are notable re-captures indicating good survival:

  • A male blackcap ringed in 2018 as an adult and another ringed in the same year as a juvenile
  • A  blackbird ringed in 2017 as a juvenile
  • A  treecreeper ringed in 2018 as a juvenile
  • A male bullfinch ringed in 2017 as an adult.

The table shows all birds caught during the 6 sessions

Dulais Valley Garden CES

The garden CES started last year as a pilot during lockdown, and the BTO decided to continue the project this year.

Feeders are allowed at garden CES (in contrast to standard CES where they are not permitted). No migrant species were captured; however a starling caught on 17 May had been ringed in February in Halloton, Leicestershire, while a male siskin caught on 22 May was subsequently re-captured on 29 May in Pembrokeshire.

The table below shows all birds captured during the 6 sessions. Just over half of the birds have been siskins. These have included juveniles, as this species breeds nearby.

Oxwich Marsh

Early morning rain reduced the weekly session at Oxwich to a few hours on 10 July. The following were captured:

Highlights were:

  • Our first fledgling Cetti’s warbler of 2021. The bird was in entirely juvenile plumage.
  • The recapture of the 2015 female blackcap also caught the previous week.
  • A reasonable day on reed and sedge warblers, with the catch of both mainly involving juvenile birds. It is good to see some evidence of successful breeding despite the very mixed weather than has characterised spring and summer to date.


The latest of our trainees to visit Skokholm were Dionne Jenkins and Miguel Lurgi. The visit was primarily aimed at getting more experience of seabird ringing. Under the supervision of Richard Dobbins and Wendy James (of Teifi Ringing Group) and the Skokholm wardens they were able to get involved in colour-ringing of adult puffins, nocturnal capture of Manx shearwaters, and ringing adult gulls (herring and lesser black-backed). They also ringed oystercatcher pulli and a few passerines in the Heligoland trap (including a bonus jackdaw which was a new bird for Miguel).

Both thoroughly enjoyed their visit, which provided very useful experience for them as they work towards their respective C permit applications. They and Gower RG would like to thank Richard, Wendy and the wardens for their patience and support during the visit.

The puffin ringing session was summarised on the Skokholm blog HERE and the gull ringing session HERE.

Gulls on Roofs

Following obtaining permission at the eleventh hour to ring gulls at the Kenfig Industrial Estate, on the south-eastern edge of the County Borough of Neath Port Talbot, a small team led by gull expert Peter Rock headed out. The roof-top colony was dominated by herring gulls, with a few lesser black-backed gulls ad at least one putative hybrid youngster. The visit was slightly later than ideal, and a proportion of youngsters had either left the roof or were too mobile to capture. Despite this, good numbers of pulli were colour-ringed, which was an excellent result and bodes well ahead of next year when an earlier visit should be possible. Peter noted that the ratio of herring gull to lesser black-backed gull was interesting, as in similar situations further east (in the Cardiff area) the latter is usually far more abundant than the former.

The team was made up of Wayne Morris, Colin Baker and Andrew Bevan, who would like to thank Peter for his persistence in securing access..


Group members continue to head out with Mike Shewring on his nightjar monitoring work in connection with the Pen y Cymoedd Wind Farm and his ongoing research into the species at other sites. Three nightjar were captured at Pen y Cymoedd last week, all of which were ringed by Miguel Lurgi under Mike’s supervision. Both male and female birds were caught. The female was radio-tagged, with a view to determining the position of the nest in relation to operational turbines (and any evidence of displacement) through daytime backtracking. This involves mounting a tag to the central tail feathers, a process requiring considerable dexterity.

These do not represent all of the Group’s activity during recent times, just a snapshot of the week, and even these don’t cover Colin Baker’s ongoing efforts at a coastal site in Neath Port Talbot or that conducted by Richard Dann in Southgate on several days last week.

Heather Coats would like to thank Colin Baker, Paul Aubrey , Dionne Jenkins and Ezra Sherwell  for much appreciated help at WWT and to Tom Wright, Dionne Jenkins and Amy Schwarz for assistance in Crynant. Thanks are also due to the team of Keith Vaughton, Val Wilson, Jo Conway, Alex McCubbin, Dionne Jenkins, Miguel Lurgi and Tom Wright for their help at Oxwich yesterday.

Photos follow, with thanks to Colin, Dionne, Tom and Miguel.

Owain Gabb


Willow tit: the highlight from the WWT Llanelli CES To date this year
Andrew Bevan (left) watching Peter Rock in action
A late herring gull nest
A lesser black-backed gull youngster on the left with a presumed hybrid herring X lesser black back on the right.
A young herring gull compared with the same hybrid type bird.
Dionne ringing a Manx shearwater on Skokholm
An adult puffin ringed as part of ongoing colour-ringing work on Skokholm. Bitey and scratchy!
Dionne and Miguel on Skokholm showing impeccable social distancing
Colour ring combination on puffin
Oystercatcher pulli
Reed bunting from Oxwich
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