In January we were delighted to learn that two of the eight juvenile ospreys that we translocated to Poole Harbour last summer had been seen at the Sine-Saloum Delta. This vast area of mangrove swamps and shallow tidal water is a perfect place for wintering ospreys, and so it was extremely encouraging that the two birds were seen there.
We have now received news of a third Poole translocated bird in West Africa, but sadly this one – LS6 – was found dead near Kartong in The Gambia. The bird’s body was initially found by local people and the corpse was then relocated by Dembo Jatta, who took the photos below. There were no obvious signs of death, and so we can only assume that it died of natural causes, which is common among young ospreys. The demands of the first migration, coupled with difficulties associated with finding a wintering site, mean that mortality among juvenile ospreys is very high, with only around 20-30 % of birds returning to the UK as adults. Juvenile ospreys are often chased away from the best areas by aggressive adult birds, and can end up in marginal habitat where food is harder to come by, and chances of mortality much greater. All manner of dangers lie in wait for inexperienced young ospreys, particularly those already in poor condition.
The body of LS6 was found by local people near Kartong in the south of The Gambia
The area where LS6 was found, just north of the River Allahein – which forms the southern border of The Gambia and Senegal – is an excellent place for wintering ospreys, but of course what we don’t know is how long he had been there before he died. Most juvenile ospreys do not settle down at a particular site until the summer of their second year, and so LS6 would still have been in the exploration phase and may have only just arrived in this part of The Gambia when he died. Sadly the bird’s body provided no conclusive evidence as to what had happened. Very many thanks to Dembo Jatta, as well as Olly Fox and Colin Cross of Kartong Bird Observatory for the information and photos.
LS6 was found just to the north of the River Allahein in the south of The Gambia
LS6’s body was found 65 km south of the location of the January sightings of LS3 and LS7
Although it is very sad that LS6 has been found dead, the fact that we now know that at least three of the eight birds we released completed migrations to West Africa indicates that they left Dorset in excellent condition; and this is testament to the superb work of the team at Poole. It is also likely that the proximity of Poole Harbour to the English Channel gives the translocated birds an advantage. The crossing from Poole to the Cherbourg peninsular in France is just 60 miles and once there the juveniles can follow the Atlantic coast of France as they migrate south, rather than attempting a dangerous crossing of the Bay of Biscay. So despite the bad news about LS6, there is plenty of reason to remain hopeful about the other birds.
POSTSCRIPT
After publishing this blog we were sent a photo of LS6 taken by Paul Hill near Kartong Bird Observatory (just 2.5 km from where the bird was subsequently found dead) on 16th January. This was just under two months before the bird’s body was found. The photo shows that a big chunk of the tail is missing – suggesting that LS6 may have been attacked by a dog, or perhaps even a crocodile. Ospreys spend a great deal of time perched on the ground, which greatly increases the chances of naive, inexperienced juveniles being predated. Although it seems LS6 had a close escape initially, it is possible that the loss of so many tail feathers impaired its ability to fish successfully. It’s a mystery that will remain unsolved, but this seems the most plausible explanation at present.
LS6 had much of his tail missing when he was photographed by Paul Hill on 16th January.
Elswehere we were delighted to learn last week that the mother of one of the Poole Harbour birds is on her way back to Scotland. 15 year-old Morven raised three chicks last year, one of which was translocated to Poole (LS7 – who was seen in Senegal in January), and another to the Basque Country. On Wednesday last week she was photographed at her regular spring stop-over site at Ría de Villaviciosa in Asturias. Morven was originally ringed as a chick on Forestry Commission land in Moray in 2003 and was then satellite tagged by Roy five years later. This showed that she migrated to the coast of Mauritania and stopped off at the Villaviciosa estuary each spring. Her transmitter was eventually removed but she continues to breed in Moray.
Very many thanks to Miguel Puente for the photo and sending details of his sighting.We have uploaded details of the sighting of Morven as well as several other new birds onto our interactive migration map.
Morven was photographed at the Villaviciosa estuary by Miguel Puente on 21st March.
