Here is a fantastic report from Field Officer John Wright, detailing his three-month-long trip to Senegal to study the osprey population! Complete with John’s excellent photographs and drawings.
Last winter, we reported that two Spanish Ornithologists, Rafa Benjumea and Blanca Perez, had found Rutland male 06(09) whilst carrying out bird surveys at Langue de Barbarie NP, Senegal for the NGO Tougoupeul. Rafa and Blanca, who I first met back in 2009 while helping to count migrating raptors at Tarifa, returned to the national park in late November 2016 to continue their bird surveys. The emphasis was on Ospreys, so I joined them to assist with their work.
Langue de Barbarie National Park, situated in north-west Senegal, consists of a narrow 16 km long peninsular of low sand dunes and small trees. The turbulent Atlantic Ocean pounds its beaches on the west side while the sheltered east, once the original entrance of the Senegal river, has now merely become a tidal inlet. A man-made 4 metre wide breach to the spit (see sketch) created in 2003 to help prevent flooding to the nearby city of Saint louis has now grown to be almost 4km wide. This breach may have been instrumental in causing the original opening to the Senegal river 20km to the south to close up in 2011. The former river mouth and Langue de Barbarie NP has now become a 16km long tidal inlet and it remains to be seen what becomes of it in the near future.
The sheltered tidal inlet provides valuable fishing for both Ospreys and local people. The Filao trees, a species adapted to sandy and salty soils, were originally planted on the sand spit to help prevent erosion but have also provided safe roosting sites and food perches for many Ospreys.
Accompanied by the park rangers, we counted, sexed and aged all the Ospreys seen along a 16 km stretch of the langue. Groups of between 20-40 Ospreys were regularly seen and an average morning count was about 150 individuals.
Rutland male 06(09) was present on his favourite stump on the east side of the peninsular but was extremely shy, taking flight long before the boat had reached him. His wintering site couldn’t have been more different from his English nesting site. The Red Kites had been replaced with Yellow-billed Kites, the Buzzards for African Fish Eagles, and the Brown Hares for thousands of Fiddler Crabs. The last time that I had seen him was in late August when he was sat in a dead Larch tree close to his farmland nest.
Local people fish and pick cockles almost continuously in the park and the sound of outboard motors and the rattle of cockle shells is rarely absent. Little is known about the fish populations within the inlet and what effect the changing landscape will have on them.
The Atlantic Ocean relentlessly pounds the west side of the peninsular but despite this many of the Ospreys remain on their chosen perches throughout the night.
One particular individual that we got to know really well was this extremely confiding adult female. She bore a Swedish metal ring on her right leg and was a bird that Rafa and Blanca had seen last year. Unlike Rutland male 06 this female would often not take flight until the boat passed 5m away and this allowed us to read five of the seven numbers on the metal ring.
Other raptors wintering alongside the Ospreys were Barbary Falcons from north-west Africa, Booted Eagles from Spain and Peregrine Falcons from Northern Europe.
Many people probably think that all Ospreys head south to spend their winter in exotic locations and, while many do, some, like the bird below, certainly don’t. This beach near Saint Louis is literally covered in discarded plastic, several kilometers of it in fact. Discarded fishing nets are probably one of the most dangerous hazards Ospreys face in West Africa. Many nets become snagged on reefs and are cut free by fisherman only to wash up later on the beach. Ospreys will often use them as perches on the shore and I saw several birds getting their feet stuck in them. People and stray dogs were also sometimes a minor inconvenience.
In total I saw 19 ringed Ospreys from Germany, France, England, Scotland, Sweden and Switzerland. The Swiss bird was a juvenile male from the translocation programme (click here for more info) and was still carrying its tail transmitter. I had a brief encounter with an adult male wearing a blue ring on its right leg, which should have been either a Welsh or English bird. However, its underwing pattern certainly ruled it out from being any of the breeding or non breeding Rutland birds, unfortunately. Male orange 11, a French Osprey, had a nice history attached to it. He was ringed at Chambord in July 2003 by our friend Rolf Wahl, and this was the first sighting of this bird since being ringed as a chick. Many colour ringed Lesser Black-backed Gulls from Western Europe also winter in West Africa.
The total number of Ospreys using the Langue de Barbarie NP could easily be in excess of 300, and the most we saw during a mornings boat count was about 180. Given that there are well over 100 Ospreys wintering with Rutland female 30(05) just a little further down the coast, this makes the coast of Senegal incredibly valuable for many of Western Europe’s Ospreys.