The Curlew conservation project in Poland was launched in 2013 and continues to this day. The reason for its initiation was the dramatic decline in the population. Over the course of two to three decades, the number of Curlews declined by more than half, from around 650-700 breeding pairs (before 2000) to approximately 250-300 (2008-2012). This bleak scenario is also well known in many other European countries, including the UK and Ireland.
In the project's first year, it was found that productivity was too low, and a further population decline would be inevitable, mainly due to high predation and agricultural intensification. After reviewing potential protection measures and their feasibility in Poland, headstarting was selected as the primary tool to boost the Curlew population. In brief, the technique involves collecting eggs from nests, incubating them in incubators, rearing the chicks in outdoor pens and releasing the young birds once they are capable of flight
Between 2014 and 2023, a total of 693 captive-reared Curlews were released in Poland. To monitor their individual fate, the birds were marked with a yellow plastic flag bearing a three-character code on the right tibia and a standard metal ring on the left tarsus. In addition, some individuals were fitted with GPS-GSM transmitters for more precise tracking. The sightings and tracking data provide us with a wealth of valuable information. One important insight we have gained is a better knowledge of the wintering grounds used by these headstarted Curlews.
To date, based on resightings and telemetry data, we have identified the winter sites of 87 of our headstarts, representing 12.5% of the total released birds. Nearly all of the wintering sites were situated along the European coastline, following the Eastern Atlantic Flyway. Only two birds were recorded wintering along the African coast, and one on the Mediterranean coast, in a lagoon between Montpellier and Marseille. The highest number of sightings came from France, with 35 individuals recorded. However, not all reports brought good news – six birds were reported as having been hunted (see our appeal).
Other locations included Spain (18 individuals), the Netherlands (17 individuals), the UK (9 individuals), the Bailiwick of Jersey (two individuals), Portugal (two individuals), Germany (two individuals), Morocco (one individual), and Senegal (1 individual).
The most unexpected finding was the individual in Senegal, 5,400 km from its release site in a straight line. This bird was observed and photo-documented in a wintering area of the N. a. suschkini subspecies. It is possible that this Curlew joined Central Asian migrants at a stopover. Who knows…
Recently, in an engaging blog post, Mike Smart detailed a Curlew marking project on the Usk Estuary and highlighted two Polish headstarts wintering there. I believe it would be valuable to introduce blog readers, particularly those in the UK, to other Polish headstarted Curlews recorded in the UK’s wintering grounds.
As mentioned earlier, we are aware of nine such individuals: J58 (aka Merry), M78, R54, R58, J07, R18, R29, T32 and 49P.
These Curlews are from eight cohorts released between 2017-2020, as well as in 2022, across both western and eastern Poland. Their winter presence has been noted along the eastern and southern coasts of England, as well as on the Welsh coast.
The first recorded Polish headstarted Curlew in the UK is J55. This bird hatched in 2018 and was released in July in the valley of the small Brzozówka River (53.580N 22.953E), a tributary of the renowned Biebrza River, an iconic site for ornithologists and birdwatchers.
The Curlew was fitted with a transmitter and named "Merry." This charming name does not reflect the bird's personality but refers to RSPB Medmerry Nature Reserve in West Sussex (50.757N 0.822W), from which the logger transmitted numerous positions. Tracking data reveals that J55 first arrived in the UK in August 2018.
Unfortunately, the GPS device ceased functioning at the end of September 2020. Subsequently, the bird was sighted twice in the UK: first in July 2022 at the Castle Coote Bird Sanctuary, a nature reserve located in Faversham, East England (51.344N 0.914E), and then again in January 2023 on the Chichester Channel (50.830N 0.815W) within the Chichester Harbour National Landscape. Notably, during one of its migrations, J55 made an extended stopover at Rye Harbour Nature Reserve (50.930N 0.761W).
This individual stands out as one of the more interesting Polish headstarts, as it did not follow the typical pattern of returning to the area near its release site for breeding. J55 flew directly to Estonia, where it is likely to nest in the coastal grasslands of Matsalu National Park (58.804N 23.522E), where it was last observed in 2020 and again in April 2023.
The second recorded Polish headstarted Curlew in the UK is M78, which, like “Merry,” hatched in 2018. Its release site was in the Bug River Valley (52.656N 22.101E). Unfortunately, we have limited information about this bird, as it was only observed once in September 2018 on the Chichester Channel (50.805N 0.860W), likely shortly after its arrival.
The third Curlew is R54. This individual was released in 2019 in the Pulwy Marsh Natura 2000 site (52.736N 21.459E) in central-eastern Poland (Mazovia region). This area is a relatively small but significant breeding ground for Curlews, consisting of peat grasslands. To help maintain this habitat, the Wildlife Society "Stork" has begun purchasing land in the area and managing it to benefit Curlews and other waders. Curlew Action visited this site during its trip to Poland in mid-April 2024 (Mary Colwell's summary post and Mike Smart's summary post). Returning to R54, it has been observed twice in the UK: once in August 2019 and again in December 2023, foraging on freshwater grazing marshes in the valley of the River Alde, south of the coastal town of Aldeburgh (52.146N 1.586W).
Another bird from the same cohort that made its way to the UK is R58. This individual was sighted in January 2022 and again in December 2022, alongside other Curlews at roosting sites on the edge of Flag Creek in the Tendring District of Essex (51.809N 1.057E).
Like "Merry," J07 hails from northeastern Poland, specifically the Brzozówka River valley (53.535N 23.068E). This bird hatched in 2017, making it the earliest of the ‘Polish-British nine’ group. Unfortunately, data on this individual is quite limited; it was only observed once in August 2019 at the RSPB Pagham Harbour Local Nature Reserve in West Sussex (50.763N 0.757W).
Another bird with limited information is R18. This individual originates from the Noteć River Valley in western Poland, where it was released in July 2019. this Curlew was recorded only once in February 2020 at Horsham Marsh (51.380N 0.635E) in Kent County, southeast England.
Resightings of the headstarted Curlews R29 and T32 headstarts were detailed in an earlier blog post by Mike Smart. I would like to quote Mike: “Among continental birds are two from Poland, both ringed with yellow inscribed flag rings by the Polish Curlew project which has been running for ten years now. R29 was released on 22 July 2019 in the Notec River valley (52.54N 16.27E) and was seen by Chris Wells at Peterstone thirteen times in different winters, the first observation on 17 October 2020, the most recent on 15 January 2023. T32 was released on 20 July 2022 in eastern Poland, in the Zelizna grasslands (51.52N 22.45E) and was noted by Chris at Peterstone on 14 January 2024, the first resighting since ringing; it has already returned to Peterstone in August 2024.”
The latest headstarted Curlew is 49P, released in July 2020 in western Poland, in the Wielki Łęg Obrzański Natura 2000 area (52.020N 16.273E). All known information about this bird has been gathered through tracking data, as there have been no reported resightings.
Before arriving in Britain, 49P stopped for quite a long time on the coast of eastern Germany. Its migration continued along the European coast, and after crossing the Brittany coastline (France), it maintained its course, flying 350 km over the Atlantic.
The bird then made a sharp turn and set a new trajectory towards the UK. 49P arrived in Wales in early September (52.603N 4.111W) and primarily explored coastal areas and their surroundings, particularly around the town of Tywyn. It visited the estuary of the Afon Leri River, where the Dyfi National Nature Reserve and the RSPB Ynys-hir reserve are located.
Unfortunately, GPS data suggests that the bird likely perished about two months after its arrival. Based on the sensor readings, we speculate that he may have fallen victim to a predator.
Captive-bred juveniles are not the only Polish curlews known to winter in the UK. In eastern Poland, we also tagged breeders with GPS-GSM transmitters. Two of the birds are UK wintering birds, a male and a female. The female's logger is working less and less, but still transmitting data. This is our longest running GPS-GSM device on the same bird. It has a full sixth years of data transmission behind it, and started its seventh year in May this year. However, more detailed accounts of these birds are best reserved for a separate blog post in the future.
Finally, a heartfelt thank you to all the observers who reported sightings of the Polish headstarted Curlews. We encourage nature enthusiasts, birdwatchers, ornithologists, and everyone else to keep a close eye on the Curlews' legs.
If you manage to read the code on the yellow flag, please report it via Euring. If you are certain, it is a Polish Curlew (only yellow coded flag on right tibia, no additional coloured legrings), you can also report it through the Polish Polring website. Our project will continue in the coming years, and we hope that new wintering Polish Curlews will emerge along the British coast.
