One of the fifteen Frisian ‘transmitter godwits’, which was still in Friesland on Saturday, arrived in Senegal in West Africa on Tuesday morning. The bird, nicknamed Heidenskip, appears to have flown from Friesland via Spain and over the Sahara in one go. The distance, over four thousand kilometres, was covered by the bird in two days of nonstop flying. Her average speed was nearly eighty kilometres per hour.
‘If you subtract the tailwind from that, you still are left with a speed of nearly fifty kilometres per hour. That’s an impressive performance’, says research leader Prof. Theunis Piersma of the University of Groningen.
In May this year, Theunis Piersma’s research group fitted fifteen black-tailed godwits in Friesland with transmitters. The researchers want to use the transmitter project to find out exactly how the birds migrate between their winter and summer grounds. Piersma: ‘That will enable us to find out exactly where these waders need to be protected.’ The godwit survey is being conducted with the help of tiny transmitters that are placed into the abdominal cavity of the birds. This transmitter contacts the Argos satellites at prearranged times, and they then send the position of the transmitter through to the researchers.
Heidenskip was named after the place in Friesland where she was caught on her nest in early May. After the godwit had had the transmitter inserted into her abdominal cavity, she just continued to brood, but a few days later she lost her clutch despite the farmer carefully mowing around the nest. After she lost her eggs, Heidenskip spent a month building up her energy reserves. During that time she roved around the area near her nest site. On 20 June the bird was spotted for the last time in the Workumerwaard, in the south-west part of Friesland. By the next check, a day later, she was flying over the Straits of Gibraltar. A day later she was ‘seen’ by the satellite on a beach just to the south of the Mauritanian capital Nouakchott. On Tuesday morning at around 10 a.m. she crossed over the Senegal river, in the border area between Mauritania and Senegal.
Too few chicks
In addition to Heidenskip, the godwit Warkum was also spotted on 22 June over the Western Sahara. The birds Bakhuzen, Himmelum and Skuzum were somewhere in southern Spain at that time and Starum was flying over Madrid. ‘At least four of these six godwits lost their clutches of eggs’, says Piersma. ‘Birds who manage to raise chicks need a bit more time to put on weight, but the first of that group is also now on its way to West Africa. This information makes us even more aware that godwits are only in our country for a very short period of time to breed, and then they quickly return “home” to Africa. That makes it all the more painful to realise that the most important bottleneck in these birds’ lives is when they are with us. Intensive agriculture means not enough godwit chicks are reaching adulthood to ensure the survival of the species’, according to Piersma.
Heidenskip was caught during the breeding season by University of Groningen researcher Ysbrand Galama from It Heidenskip and the Mauritanian biology student Hacen ould Mohammed el Hacen. ‘A wonderful coincidence’, thinks Piersma. ‘Of the fifteen godwits fitted with transmitters, Heidenskip is the first to reach West Africa. She’s really living up to her name – the 380 inhabitants of It Heidenskip are famous in Friesland for their relatively high number of sporting heroes, including ditch vaulting (fierljeppen), pole climbing and tug-of-war. On top of that, Heidenskip flew back to Hacen’s homeland – Mauritania.’
The transmitter project is a joint project of the University of Groningen, the Alaska Science Center of the US Geological Survey, ecological research bureau Altenburg & Wymenga and the Nederland-Gruttoland coalition. The project is supported financially by the Department of Knowledge of the Ministry of Agriculture, Nature and Food Quality and the Province of Friesland. The birds can be followed via http://www.vogelbescherming.nl/grutto
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