Tracking Wood Lane’s wandering Curlews

Many years ago in the late 1970s and early 1980s when I was a trainee bird ringer, I used to visit Wood Lane sand quarry to ring Sand Martins with my trainer Chris Whittles. Chris was also very keen on Curlews which we used to ring at the old Allscott Sugar Beet Factory near Telford. In those days there may have been upwards of 200 Curlew roosting on the lagoons in the autumn and we would occasionally catch birds that were older than I was at the time which was pretty mind-blowing.

In 2000-2003, following discussions with John Hawkins the warden, I returned to Wood Lane to ring Sand Martins but also to mist-net Curlew and other passage waders on the settling pools, including the newly designated Shropshire Wildlife Trust Nature Reserve.  At that time the Curlew roost at Wood Lane numbered well over 50 birds on occasions and, over the course of four years, I ringed a total of 56 individuals. These birds were fitted solely with BTO metal rings and as a result few recoveries/sightings resulted.

 

Moving forward a few years. In August 2024 by kind agreement of Tudor Griffiths (the owners), Shropshire Wildlife Trust (the site managers) and John Hawkins I was once again granted permission to catch Curlews on the reserve. I had sought permission as I wanted to try and catch some of the birds to fit GPS trackers that had been funded by Natural Resources Wales for attachment to Curlew breeding on Whixall Moss. These GPS tags, costing about £1,000 each, are game-changing in making it possible to track the movements of individual birds in great detail. Despite much effort I had only managed to fit two tags to birds at Whixall in 2023 and one more in 2024.  The breeding birds at Whixall nest in such close proximity that their territorial behaviour is switched off somewhat and they are far less aggressive to other Curlews in their territory making our usual trapping technique (involving a sound lure and decoy) somewhat ineffective.

 

The GPS tag data showed that the tagged birds nesting on Whixall moved to Wood Lane after the breeding season so it was assumed that most of the birds at Wood Lane in the autumn were likely to be Whixall breeders too.

 

On the evening of 14^th August 2023 Adrienne Stratford and I set mist nets across the pool in front of the hide and waited. Just before dusk a flock of 24 Curlew approached the pool, circled overhead but had clearly seen the nets and headed-off again. Like most waders Curlews have excellent eyesight and are unlikely to fly into a net during daylight hours, we would have to wait and hope they returned after dark. 

  

 

A few hours later, after a brief but busy session, we had caught 14 of the 24 birds. One of the birds already had colour-rings and a GPS tag fitted and was confirmed as a breeding male from Whixall Moss caught in April 2023. Two other birds already had BTO rings only. One was one of the 56 BTO metal-only ringed birds originally caught by me at Wood Lane 23 years earlier and the other had been ringed there by Shropshire Ringing Group in 2009. Both these birds, plus 11 others, were fitted with colour-rings and 3 were also fitted with Lotek Cellular GPS trackers that work via the 2G mobile network.

 Curlew with Lotek Cellular GPS tracker fitted

It might reasonably be assumed that birds congregating in a flock to moult at one location might all be birds from the local breeding population and show similar winter dispersal patterns following completion of their annual moult?  How wrong can you be!

 

The birds caught and tagged that night showed very different movements subsequently.

One bird, Yellow 6N, moved to Isombridge near Telford on 24^th November 2023. He spent the rest of the winter there before moving, on 12^th March 2024, to presumed breeding grounds near Bewdley then, post-breeding he moved on to Worcestershire Wildlife Trust’s Upton Warren reserve for a stay before returning to Wood Lane on the night of 11^th/12^th August 2024.

  

Another bird, Yellow 6J, moved from Wood Lane direct to the Dyfi Estuary near Ynyshir on 3^rd September 2023 where she spent the whole winter returning to the flood plains of the River Dee near Wrexham on 19^thFebruary 2024 where she stayed until 8^th March 2024 when worryingly all contact was lost.  It was subsequently discovered she was alive and well but her tag had failed. 

 

 

Photo ©John Harding

 

The final one of the three Curlew tagged at Wood Lane in August 2023, Yellow 6H, made a sudden over-night movement to near Limerick on 4^th September 2023 where she spent the rest of the winter before travelling back to a presumed breeding location near Allenheads in the North Pennines on the night of 28^th/ 29^thFebruary 2024. She returned to Wood Lane via Barnard Castle (got her eyes tested?), Shap, Morecambe Bay and Blackpool on 1^st July 2024. Shortly after, on 6^th August, her tag came off and I managed to recover it with the help of the farmer whose land the birds had been feeding on. This tag was redeployed on a female caught at Wood Lane on 23^rd Sept 2024 (see below for details).

 

        Photo ©John Harding

 

 

In autumn 2024 at least 13 of the 14 birds caught the preceding year were photographed back on the Reserve Pool by John Harding confirming the well-known fact that adult Curlews are long-lived with an annual adult survival rate in excess of 90%

 

Following a repeat request we were granted permission for another catching attempt and on 23^rd September 2024, Adrienne Stratford, Jack Slattery and I once again set nets across the pool and waited for darkness to fall. On this occasion, a bit later in the year than the 2023 attempt, just 14 birds turned up at dusk and we managed to catch five of them. One was the same tagged male we caught in 2023 but the GPS tag had since stopped working so we removed it.  One was another one of the 56 BTO-only birds ringed by me at Wood Lane 22 years earlier and the other 3 were unringed. These three, along with the old re-trap, were fitted with colour-rings and one, Yellow 7L, was also fitted with the GPS tracker recovered from 6H.

 

Yellow 7L, stayed very local to Wood Lane feeding either in the main sand pit or on fields near Crosemere until early January when, presumably in response to the prolonged cold spell, she made a sudden over-night movement to Belgooly, Cork on 8^th/9^th January 2025. We have our fingers crossed that she may return as a Whixall breeding bird in February or March.

 

 

Interestingly Yellow 6N from 2023 returned to Upton Warren in Mid-December rather than spending time at Isombridge as he did last winter.

 

                            Yellow 6N at Upton Warren          Photo © Clive Appleby

As fascinating as these movements are it is also important to identify the resources, in terms of water bodies for roosting, locations for nesting and fields for foraging that these birds are utilising on a regular basis so that conservation initiatives might be correctly deployed to the most important areas. The map below shows the locations Yellow 6H was using during July 2024. It can be seen that besides Wood Lane, where she was roosting and resting, she was only actually visiting a small number of fields for foraging. It should also be noted that at this time 6H was one of a regular flock of ca. 22 birds, all presumable utilising the same resources.

Colour-ringing has shown that adult survival rates in Curlew are high but research during the breeding season in many areas of the country has highlighted the dire state of the recruitment of young birds. Few local Curlew populations are currently able to rear sufficient young to replace even low levels of adult mortality.  GPS-tagging can supply large amounts of data on habitat usage throughout the year. The more we know the better able we are to make informed decisions about targeting limited finances. In an area where old pastures are constantly being ‘improved’, ploughed, re-seeded or planted with maize having detailed maps of favoured feeding areas could help to best preserve those areas that are vital to the continued survival of the adult population. Curlew populations everywhere have a difficult future and virtually no-one who works on Curlews is very optimistic about their prospects but if adult mortality increases due to continued habitat deterioration the demise of lowland Curlews will be considerably hastened. Turning back the clock on agricultural development is impossible, as is stemming the tide of future ‘improvement’ but protecting a few key breeding and foraging sites is more achievable and could make a huge difference.