LS7 seen in Senegal

It is always exciting to receive reports of colour ringed ospreys during winter, but earlier this week we got an extra special one. On Monday Adama Lene, a ranger at the Saloum Delta National Park in Senegal, was out surveying birds at the aptly named Ile des Oiseaux; a long sandy island that lies at the mouth of the delta, with the Atlantic Ocean to the west and 180,000 hectares of shallow water, inter-tidal mangroves and savanna woodland to the east. It is named after the thousands of Caspian terns which breed there each year, but in winter ‘Ile des Balbuzard’ would probably be more appropriate. It is not uncommon to see 20 or 30 ospreys perched within close proximity on the sand. Fishing is easy in the rich, shallow waters of the delta and the island provides the perfect place for the wintering ospreys to eat their catch and then rest during the day. Both myself and Roy have been privileged to visit the island on a number of occasions and each time we have seen colour ringed ospreys, including several birds from Scotland as well as others from Germany. As they eat their fish on the sand, with blue-cheeked bee-eaters zipping around overhead, the ospreys are surrounded by turnstones and slender-billed gulls which often steal pieces of fish. In 2011 Roy visited Ile des Oiseaux with BBC Autumnwatch and observed this interesting behaviour. Click the link below to watch.

Having been with us when we’ve been checking out the ospreys for colour rings Adama is well versed in what to look for. Now each time he visits the island, he checks the assembled ospreys for ringed birds.  On Monday he was pleased to see an osprey with a blue ring on its right leg, bearing the inscription LS7. He didn’t know it at the time but, amazingly, he had found the proverbial needle in a haystack: one of the juvenile ospreys that we translocated to Poole Harbour last summer; and the first sighting of any of the birds since they left Dorset.

Many juvenile ospreys are chased away from the very best sites by adult birds when they first arrive in West Africa, and are pushed into peripheral habitat where their chances of survival are greatly reduced. It is extremely encouraging therefore that LS7 is at such an excellent site. Although there is no guarantee that he will stay – young ospreys usually explore over thousands of square kilometres during their first winter in Africa – Ile des Oiseaux will now be on his radar; meaning that even if he continuous his wanderings, he may well return at a later date.  Our satellite tracking studies have shown that most juveniles eventually settle at a specific site after about six months in West Africa, which coincides with adult birds heading north again. Most juveniles, on the other hand, remain in Africa for the whole of their second calendar year which helps them to get established at their chosen site.

Ile des Oiseaux lies in the mouth of the vast Sine-Saloum Delta in Senegal, just north of The Gambia

LS7 was the first of the birds to fly after release on 31st July

LS7 was the first of the translocated juveniles to fly after release on 31st July and also the first to set-off on migration, on 25th August. It is very apt therefore that he is now the first to have been seen since leaving Dorset. The first 12 months of a young osprey’s life are incredibly demanding and we do not know how many of the seven other birds from the 2017 cohort survived their first migration. Colour ringing and satellite tracking studies show that they could be wintering anywhere from Spain to the Ivory Coast, so the fact that we now know where one of them is, is remarkable. The return rate of translocated ospreys to Rutland Water was only around 20%; so in all likelihood we may see one or two of the 2017 birds returning next year. Adama’s sighting suggests there is every chance that one of them will be LS7; especially if he settles at the island of the birds.

Wintering ospreys often perch together on the Ile des Oiseaux (photo by John Wright)