Osprey AW

Male Osprey AW fledged from the Site B nest in 2006. He bred for the first time in 2010 at Site O (a nest on private land near Rutland Water) and again in 2011 with a Scottish female from Argyll. AW then spent several months wintering in Africa, but in February 2012 his transmitter stopped sending data. Subsequently he failed to return to Rutland for the 2012 breeding season.

AW at his winter home

The latest data from AW’s radio proves that he has reached his winter home. Having roosted in the mangroves 500m from the shoreline on Friday evening, the GPS position at 8am showed him fishing just over 3km out to sea. An hour later he was back in the mangroves, presumably eating the fish.

 Like most adult Ospreys at their established wintering site, AW will probably spend the winter in a very small area – using the same perches each day. It will be really interesting to follow his daily routine over the coming months.

AW fishing 3km out to sea

AW has made it to Guinea – and probably his winter home

Just after 3pm yesterday AW arrived on the Guinea coast 75 kilometres south of the border with Guinea-Bissau. On every other day of his fourteen day migration to West Africa he has flown until early evening, but yesterday was different. He spent the rest of the afternoon in a small area of mangroves, making one short flight to fish. It looks like he has reached his winter home.

AW's movements on the Guinea coast

Earlier in the morning AW hadn’t left his roost site until after 9am. He was fishing in the River Corubal at 7am and then must have spent a couple of hours eating it. He obviously knew that there was no need to rush.

By 10am he was heading south at 17kph and he crossed the border into Guinea just after 11am. At this point he switched to a south-easterly heading and this took him to the coast. He arrived just after 3pm after a day’s flight of just under 200km.

AW's flight, 9th September

If AW has reached his wintering site, then it has taken him just 14 days to get there; surely one of the fastest Osprey migrations recorded anywhere in the world? He covered 5274km (3277 miles) on his two week journey, an average of 376km a day. What an incredible migration.

AW's migration to Guinea - 27th August-9th September

AW reaches Guinea-Bissau, now how much further?

As we suspected, AW continued south through Senegal yesterday; skirting the eastern border of Gambia, and eventually roosting next to the River Corubal close to the Guinea-Bissau-Guinea border.

Having roosted in central Senegal AW set off again just before 9am and flew 150 kilometres south-west towards Tambacounda, the largest city in eastern Senegal. He skirted around the city at 2pm and turned slightly south-east, passing over the very eastern tip of Gambia. He continued on this course until 6pm when he turned south west as he crossed the border from Senegal into Guinea-Bissau. He continued for another 68km before stopping beside the River Corubal as dusk was falling at around 7:30pm after a day’s flight of just over 350km.

AW's flight, 8th September

The River Corubal is 150 metres wide and bordered by mangroves; typical over-wintering habitat for Ospreys in West Africa. On our trip to West Africa last winter myself and the team from Rutland Water saw numerous Ospreys perched in this sort of habitat. The resolution on the Google Earth images for this part of Guinea-Bissau isn’t good, but AW’s position at 9pm suggest that he roosted on an island in the river.

It is not inconceivable that AW has reached his winter home but the fact that he was flying right up until dark suggests thast he may well continue further south tomorrow. If he does then he could be in southern Guinea or perhaps even Sierra Leone by tomorrow evening!

AW's roost, 8th September

AW in central Senegal

He’s done it! It is just 11 days since AW left his nest close to Rutland Water, but he has already crossed the Sahara and reached Senegal. At 9pm last night he was in Reserve de Faune du Ferlo-Nord an extremely remote part of central Senegal, 112 miles miles west of the town of Touba.

The previous batch of data had shown that AW was in southern Mauritania at 5pm on Tuesday evening and the latest GPS fixes show that he continued heading south for another 54 kilometres before eventually settling to roost 15km north of Lake Aleg, before 7pm. He was now just 82 kilometres from the Senegal border. According to the Birdlife website “Lake Aleg is a closed depression in an old course of the Senegal river fed by rainwater run-off.  The lake is endorheic and semi-permanent and typically varies in depth from 1–2 m at the end of the dry season to a maximum of 3–4 m at the end of the rains.” In winter it is home to more than 50,000 Garganey, who like AW will cross the Sahara from northern Europe.  Despite being so close to the most significant piece of water he would have seen for days, the satellite data suggests that AW did not fish in the lake that evening. Perhaps he was just too tired? In fact he was now starting to show some signs of fatigue – his day’s flight of 330km was 100km less than the distance he covered during the previous two days. He had every reason to be tired  – he had now crossed the Sahara and had covered an incredible 2400km since Saturday morning.

AW's roost at Lake Aleg, 6th September


Next morning AW was migrating again by 9am, heading south east at 27kph. Like the previous evening there is no data to suggest that he visited the lake to go fishing, but the gap in data means that we can’t rule it out. AW made steady progress south east during the morning and by midday he had covered 90km. At this point he made a very obvious change of direction – shifting his course to south west.

At 2pm he was flying over the Senegal River, but once again the data suggested that he didn’t stop to fish. He was flying at an altitude of 260m and an hour later was another 28km further on.

AW over the Senegal River

He covered another 50km on the same south-westerly course but at 5pm changed direction again, this time heading south east. By 9pm he was at roost 40km further on having completed a day’s flight of 269km. This final change of direction is very interesting and suggests that rather than heading to Gambia and Senegal, AW may be on his way further south – perhaps to Guinea-Bissau? Although he made a couple of deviations during the day, his roost site was almost due south of his position the previous night.

Irrespective of exactly where his wintering site is, if he continues at his current rate, the chances are that AW will be there by Saturday. If this is the case he will have reached his winter home in just two weeks. Truly remarkable!

AW's flight on 7th September

AW has Senegal in his sights

We already know that Ospreys are master migrators, but AW’s latest data demonstrates it once again. At 5pm this evening he was just 80 miles north of the Senegal border. This means he has just about crossed the Sahara in three days!

The last batch of data had shown that AW had crossed into Mauritania at around 2pm on Sunday afternoon. He had already flown more than 250km since leaving his roost site and he was cleary determined to get across the desert as quickly as possible. The position at 2pm showed that he was flying SW at 23kph and he continued to make steady progress all afternoon. By the time he settled to roost at 7pm he had flown another 277 kilometres, stopping just east of the border with Western Sahara. Like the previous evening he would have roosted on the desert floor. When John, Paul and myself were in northern Senegal last winter we saw an Osprey perched on the ground in a sandstorm. It was a truly evocative sight and looking at Google Earth now I can imagine exactly what AW must have looked like perched in the vast wilds of the Sahara on Saturday evening.

Male Osprey perched at Djoudj, January 2011

A gap in the data means we don’t know what time AW left his roost site but by midday he was 122km further on, heading south west at 46kph. He maintained a remarkably consistent course during the afternoon and eventually settled to roost before 7pm after covering 270 kilometres. There are some truly incredible land forms in the desert and AW’s Sunday night roost site demonstates that. He roosted in a valley surrounded by rocky hills rising to 1500 feet. Perhaps he was sheltered from the desert winds down in the valley? He was just 10km west of the village of Terjit – without doubt one of the most isolated places of human habitation on the planet!

AW's roost in the valley floor, 5th September

Next morning AW had moved 14km further south and he recommenced his migration just before 9am. He made slower progress than the previous day, but by 3pm he had covered another 200km. He flew a further 75 kilometres in the next two hours, still heading south west. The last position in this batch of data showed him flying south west at 24kph. He was now just 130 kilometres from the Senegal border, and more importantly, the Senegal River. There is every chance that as I write he will be perched close to the vast river, perhaps eating his first fish for at least three days.

AW has flown a remarkable 2050km across the Sahara since 8am on Saturday morning. I wonder how much further south he will go?   The latest data will be on Google Earth by tomorrow morning, in the meantime, here is a map of AW’s incredible flight since Saturday.

AW's flight across the Sahara 3rd-6th September

Finally, here are some photos that John took from the plane windown as we flew over the Sahara en route to West Africa last winter. They really do demonstrate what a desolate, barren place it is.