Previously published on the blog Quest of Quist in 2009.
It is the time of the year when we should lean back and search the skies for migrating Ospreys, which are already a daily presence along the coast at Dakar.
In December 2008, Professor Dr. Bern U. Meyburg requested my assistance to retrieve a GPS transmitter from an Osprey, which had died in the Sine Saloum delta in Senegal. This gave me some insight into a fantastic migration story.
Through his programme, Raptor Research, Professor Meyburg has for many years studied the migration of raptors between breeding areas and the wintering sites, in recent years with the use of solar powered GPS transmitters.
On the 21st of June 2008, an Osprey was trapped and fitted a small GPS transmitter, no.81340. This happened at Lake Müritz in northern Germany only 16 kilometers from the place where it was ringed as a nestling 8 years earlier. Four times daily the GPS transmitter would upload position, speed, heading and altitude of Osprey 81340 on its 3,100 km migration route from northern Germany to Senegal.
Osprey 81340 started its southwestern trip across Northern Germany, into Holland, Belgium, through France and across Spain. Then it did something unusual. Instead of taking the short route over the strait of Gibraltar, which offers only 15 km open water, it crossed the Iberian coastline near the Spanish/Portuguese border and headed into the Atlantic by night. It did not turn towards the African Continent until much further south in Morocco.
Osprey 81340 continued south in Morocco, left the coastline and crossed Western Sahara and Mauritania inland. By October it reached northern Senegal.
Once again Osprey 81340 did something unusual. According to Professor Meyburg the majority of Ospreys have small winter home ranges along rivers in Senegal or the Gambia. But in October and November 81340 stayed for a long while at the Atlantic coast approximately 130 km north of Dakar. Professor Meyburg asked me to explore the area based on coordinates.
It was an arid area – quiet different to Osprey 81340’s flush and green breeding area in Germany. Behind a white sand beach was a 200 – 300 meter broad belt of wind bent trees. This was where 81340 rested. And behind the tree belt was semi-desert (photo). There were a few villages but not many people. The nearest tarmac road is 30 km to the east.
In mid December Osprey 81340 left its sandy and windy beach and continued east of the Dakar peninsula and flew via the coastal region south of Dakar towards the Sine Saloum delta. Shortly before Christmas, Professor Meyburg unfortunately received a telephone call that Osprey 81340 had been found dead in the Sine Saloum delta. (His telephone number was printed on the GPS).
Professor Meyburg asked me to retrieve the GPS transmitter and I went to an area inland of Joal-Fadiouth, where I met the finder and his family. The finder told me that he was out fishing with cast net in the delta (photo), when he discovered Osprey 81340 perch ill or exhausted in one of the mangrove bushes. When he returned a couple of hours later the bird was dead and the finder secured the GPS transmitter and its rings.
The finder and his family were poor people. Their diet consisted almost entirely of locally produced couscous, because rice was too expensive. They got protein by eating small carp caught in the delta. A pig was bound behind one of the huts. It waited (not with glee) for a festival. A pig is an unusual domestic animal in Senegal. The Finder and his family were Catholics in the 89% Muslim country.
But what did Osprey 81340 actually die off? This was discussed thoroughly in the African Bird Club’s mail group. According to Professor Meyburg it had only flown very short distances in the days up to its death. Not distances which in any way could exhaust it.
It was suggested that it by accident could have become tangled in fishing net while foraging, but I did not see fixed net installations at all where the bird was found, and this did not tally with the finder’s explanation.
How Osprey 81340 really died will remain a mystery. But perhaps, when it comes to it, an Osprey is not necessarily on top of the food chain.
Anyway, the brave bird did 1,300 km from Lake Müritz in Germany to Sine Saloum delta in Senegal.