Colour-ringed Curlews on the Usk estuary

During the winter of 2015/16, a BTO/WWT team caught and colour-ringed 41 adult wintering Curlew in the general area of the Usk Estuary, between Newport and Cardiff, in south Wales. The purpose of the work, supported by Tidal Lagoon Power, was to study the local movements of the birds to inform the assessment of proposals for the potential development of tidal lagoons in the Severn Estuary.

Four birds were ringed at Lighthouse Saltmarsh on 14 December 2015 and 22 at Lighthouse Beach on 15 December 2015 (both near the West Usk Lighthouse on the west bank of the Usk); another 15 were ringed at Newton Farm, further west just beyond Peterstone, on 15 January 2016. Thirty of the birds were fitted with Pathtrack GPS tags, which gave high-quality data on the birds’ positions during that winter. Just one of the 41 birds (a Newton Farm bird) was already carrying a metal ring: it had been ringed on the Taff Estuary, prior to the closure of the Cardiff Bay barrage, on 16 January 1997, so was at least 20 years old when re-ringed in January 2016.

Some observations were carried out in the period immediately after ringing sessions, to record colour-ringed birds. In all, 21 of the 41 ringed birds were re-sighted  between mid-December 2015 and mid-January 2016, all of them ‘Lighthouse’ birds; a ‘Newton Farm’ bird was re-sighted in late January and mid-February 2016 near Cardiff heliport. The GPS tags provided valuable data on  the areas used by the birds (see for more information). For example, birds ringed at Lighthouse Beach or Lighthouse Fields appeared both at high tide roosts on the foreshore along the west bank of the River Usk and along the foreshore east of the Usk.  Relatively few birds used the Goldcliff Lagoons further east. Birds also used the fields just inside the seawall along the west bank of the Usk.

In the period between January 2016 and August 2019, there have been remarkably few further records of these colour-ringed birds on the Severn (although experiences with other colour-ringed populations suggest that birds are likely to have been site-faithful to their wintering grounds). Just eight of the 41 colour-ringed birds were reported in this period (all Lighthouse ringed birds, no Newton Farm birds), on five dates between 18 September 2016 and March 2017; of these eight, six had been seen in winter 2015/16.

Some of the colour-ringed birds have, however, been seen away from their usual wintering grounds on the Severn since ringing. Three of them have provided spectacular recoveries on foreign breeding grounds in northwest Europe: one in Finland, one in Poland (each seen in 2018 and again in 2019, and both already featuring in news items on this website), and a third in northern Sweden in June 2016.

Two more have provided interesting re-sightings in the UK: one was seen by John Sanders, further up the west bank of Severn Estuary in Gloucestershire on 19 April 2016, this must have been a migrant on its way back to its breeding grounds, presumably a bird going far to the north of the breeding range, given the late date: John spends a huge amount of time looking at colour-ringed Curlews in the Severn Estuary, and this is the only Usk-ringed bird he has ever seen in his patch (JDS, pers. comm).  The second UK recovery comes from Alston Reservoir in Lancashire on 27 April 2019: it is not yet clear whether this bird was nesting on nearby moorlands, or whether it was en route to nesting grounds further north: further research and sightings required!

German ringed bird – photo by Neville Davies

Since the end of August 2019 there has been a concerted effort by local observers, many of them members of the Gwent Ornithological Society (GOS), to increase the number of observations of these colour-ringed birds, particularly around the Usk Estuary and the Newport Wetlands National Nature Reserve. So far, 17 of the original 41 birds have been re-sighted since August 2019, all of them Lighthouse birds (thus 65% of the 26 ringed there), reflecting the location focus of re-sighting efforts and the birds’ high site-fidelity and survival rates. Twelve of the 17 had been re-sighted in winter 2015/16, five of them were from the eight recorded in 2016/17. Of the birds recorded at sites away from the Usk, the individuals that nest in Poland (Black White Orange) and Sweden (Black White Green) have been recorded, as have the birds seen at Alston Reservoir (black Orange Green) and on the Gloucestershire Severn (Black Blue Orange), though not yet the Finnish bird. The 20-year old re-ringed at Newton Farm in 2016 (Black Black Orange) has not (yet) been re-sighted. As already noted in a separate news item on this website, one colour-ringed bird from Newton Farm (Orange White Red) has been observed at the Wildfowl and Wetlands Trust centre on the Burry Inlet at Llanelli in Carmarthenshire (some 60 miles to the west of the Usk estuary); it now transpires that this bird has been seen on four occasions between August and October 2019 at Llanelli, so appears to be wintering there.

NBO – photo by Neville Davies

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