Jules

Jules (Blue JV3) is an adult male osprey of unknown age who was caught and satellite tagged by Roy Dennis and Frank Law at Rothiemurchus Fishery on 13th September 2017. Our thanks to Julian Orsi and Rothiemurchus Estate.

Daily routines

Over the past two decades satellite tracking has provided a unique insight into the wintering behaviour of ospreys. Whereas juveniles usually wander over a large area after arriving in West Africa, adults head straight to a known wintering site. Many of the adult birds we have tracked have been remarkably sedentary in winter; often occupying a home range of 1-2 km². There are always exceptions to this rule, however, and it has been fascinating to follow the daily movements of Jules since he arrived at his winter home in the Casamance region of southern Senegal. Jules is living in a larger area than most adult ospreys, but mainly because his regular roost site is 16 km from his favoured daytime perching and fishing sites.

Jules has spent each night roosting in an area of dense mangroves, and has four favoured perches within an area of just 0.04 km².

Jules roosts in an area of dense mangroves each night.

In this part of the Casamance delta he is surrounded by potential foraging grounds, including a section of river that is almost 1 km wide, just 2 km to the south. However the satellite data indicates he does little or no fishing in this area, and instead flies 16 km WSW to spend each day on the coast. There he favours a 1.3 km stretch of sandy beach and hunts just offshore. The satellite data indicates he probably catches most of his fish around 200 m out to sea, but on occasion he flies further out, such as 1.1 km on 3rd December and 2.65 km on 19th November. Most of these fishing trips tend to be late morning or early afternoon, and he then eats his catch on the beach.

Jules spends most days perched on a sandy beach, and fishing just offshore.

The map below gives an indication of just how predictable his daily routine is. The red circle, centered on his roost sites, indicates an area with 50 % of GPS fixes while the orange area shows the location of 95 % of fixes. In other words, when he is not at his roost site he is nearly always at the coast. Interestingly he has flown east from his roost site on just two occasions in the past month.

Over the past month Jules has roosted in the mangroves each night and then flown 16 km WSW to spend the day on the coast. The red circle indicates an area with 50% of GPS fixes and orange shading 95% of GPS fixes (calculated using kernel method).

Jules’ winter home in Senegal is 30 km south of The Gambia and 20 km north of the Casamance River.

Don’t forget that Jules’ latest winter movements as well as his migration from Scotland are shown on our interactive map.

Wintering in Casamance

In our last update we reported that Jules set-off across the vast wilds of the Sahara on 19th October. We now know that he completed his desert crossing just over three days later and is now settled in the Casamanace region of southern Senegal, 30 km WSW of where Blue DF is wintering.

Jules made a superb start to his desert crossing on 19th October, flying 519 km across the spectacular land forms of the north-west Sahara. He crossed the disputed border between Morocco and Western Sahara at 11:00 GMT and then maintained speeds of almost 50 kph during the afternoon, passing into Mauritanian airspace at 15:09 before settling to roost at sunset in remote north-west Mauritania. The Google Earth imagery suggests that Jules would have had to roost on the ground, and it seems that he was disturbed during the night because at 23:00 he took off again and flew 25 km south-west.

He moved a further 22 km south-west before dawn next morning and then resumed his migration at around 08:30. Conditions must have again been in his favour because he flew a further 423 km south-west during the course of the day before roosting close to the southern border between Western Sahara and Mauritania. Next morning he was away before dawn and flew 67 km south-west before pausing again at 08:06. After resting for an hour he resumed his journey and maintained a constant SSW heading for the rest of the day, covering a further 418 km across the Akchar and then Trarza desert regions. By the time he settled to roost at 19:00 he was within 100 km of the Senegal border having flown 485 km from his overnight roost and a total of 1474 km in just three days; a superb Saharan crossing.

Jules flew just under 1500 km across the Sahara in three days

On the morning of 22 October Jules set-off at first light and shortly after 09:30 he reached the Senegal River; his first sight of water for at least four days. Many European ospreys winter in this northern part of Senegal but Jules showed no signs of letting up. After crossing the river just to the west of Richard Toll he headed south along the eastern shore of Lac de Guiers and then onward across the arid north of Senegal. At 16:34 he reached the Atlantic coast at the northern edge of the vast Sine-Saloum delta. He continued flying for a further two hours before settling to roost in one of a myriad of mangrove-lined creeks in the delta, 7 km north-west of the village of Missirah; a place both Roy and I have visited several times.  Having flown 461 km from southern Mauritania, it had been another excellent day’s migration.

Sunset at the Sine-Saloum delta (photo by John Wright)

Jules obviously sensed that he was now close to his winter home because he set-off before first light next morning and at 07:22 was 25 km further south on the north bank of the River Gambia. He was then perched for an hour, perhaps eating a fish, before continuing south across the river and then back in to Senegal at around 11:00. Once in Senegalese airspace he turned to the south-west and flew directly over Blue DF’s wintering site at 13:00 – they would almost certainly have seen each other – before heading another 30 km west and eventually settling in a mangrove- lined creek on the north side of the Casamance River, having flown 153 km during the  course of the day. He was now very close to where another of our satellite-tagged ospreys, Blue XD used to winter.

Jules (pink line) flew directly over the area where Blue DF (blue) is wintering – they would almost certainly have seen each other

After arriving in Casamance on the afternoon of 23rd October Jules has roosted in the same location every night, but, interestingly, has made almost daily flights to the coast near Boko in an area of 75 km2 – far larger than the usual wintering range of most adult ospreys. It will be fascinating to see if he continues in the same vein over the coming weeks. Whatever the case, we can now be certain that he has reached his winter home.

Since arriving in Casamance on 23 October, Jules has made daily flights to the coast

Jules and Blue DF are wintering just 30 km apart in Casamance

Now that Jules has arrived at his wintering site we know that he flew a total of 5717 km during 17 travelling days. His overall migration, however, took 40 days to complete because he spent 23 days on stop-overs in France and Morocco. This migration strategy contrasts greatly with that of Blue DF who migrated  5494 km in 19 days without stop-overs. A summary of Jules’ flight from Scotland to Senegal is shown below. You can also check out his route on our interactive map.

Migration tracks for Jules (pink) and Blue DF (blue)

Date Distance (km) Location
14 Sept 420 Scotland-England
15 Sept 584 England-France
16 Sept 122 France
17 Sept-2 October Stop-over, Gulf of Morbihan, France
3 Oct 515 France-Spain (Bay of Biscay)
4 Oct 181 Spain
5 Oct 462 Spain
6 Oct 168 Spain
7 Oct 75 Spain
8 Oct 524 Spain-Morocco (Atlantic)
9 Oct 127 Morocco
10-16 Oct Stop-over, Morocco
17 Oct 128 Morocco
18 Oct 323 Morocco
19 Oct 544 Sahara
20 Oct 445 Sahara
21 Oct 485 Sahara
22 Oct 461 Senegal
23 Oct 153 Senegal-Gambia-Senegal

 

Around the Atlas

In the last update we speculated as to how long Jules would remain in Morocco, or even if he would stay there for the winter, as a small number of European osprey do each year. However we now know that after spending just over a week on the coast between Casablanca and Safi he resumed his journey south at around 12:30 local time on Tuesday afternoon.

After arriving on the Moroccan coast on 9th October Jules initially favoured an area near Ouled Salam, spending his days along the shoreline, and then roosting 8 km inland. Then on 13th October he moved 20 km south to Oualidia where his daily routine was much the same; favouring an area of saltpans to the north-east of the town during the day before roosting a few kilometres inland.

Jules spent a week on the Moroccan coast between Casablanca and Safi

He finally resumed his migration at lunchtime on 17th October, flying 104 km south-west before turning more to the south at 16:21 and continuing onward for another two hours. He settled to roost 40 km north-west of Marrakesh at around 18:15 local time having flown 128 km during the course of the afternoon.

At 08:15 next morning Jules was perched beside a river 5.5 km south of his overnight roost and an hour later he had moved 2 km south-west, and was probably eating a fish. He resumed his migration at around 10:00 passing to the west of Marrakesh and onward towards the Atlas. These imposing mountains are a barrier to migrating birds and as Jules approached he changed his heading to west-south-west to avoid the high peaks. Over the course of the next five hours he flew south-west and then south around the western end of the mountains, flying at a maximum altitude of 2032 m. The video below shows his flight around the mountains.

By 17:00 Jules had flown 184 km and was south of the mountains but he showed no signs of letting up. He continued on a south-east and then south-west course for another five hours, covering another 139 km, before finally setting to roost two hours after sunset at 20:51. He had now reached the northern edge of the Sahara and he roosted at the top of a remote cliff face after a day’s flight of 323 km.

Jules roosted on the top of a cliff face on Wednesday night

Yesterday morning Jules left his roost site more than two hours before dawn and by 07:24 local time he had already flown 65 km. We haven’t received any data since because, as he heads across the Sahara, Jules will be out of the range of mobile phone masts. It will be fascinating to see where he is when the next batch of data comes through. You can check out his flight so far on our interactive map.

Jules’ flight through Morrocco 9-19 October

Into Africa

The previous data had shown that Jules crossed the Bay of Biscay from Brittany to northern Spain on 3rd October. Next morning he resumed his migration shortly before midday and set off south through the mountains of Asturias passing peaks of over 2000 m. By 15:59 he was south of the highest mountains, and he continued flying until almost 20:00 when he settled to roost among scattered trees near Une de Quintana after a day’s flight of 181 km.

Jules flew through the mountains of Asturias in northern Spain on 4th October

At 09:20 he was perched beside a large reservoir 9 km to the south and an hour later had moved 2.5 km south and was probably eating a fish. By 11:18 he was migrating again and he made excellent progress south, passing into Extremadura soon after 16:00 at an altitude of more than 2000 m. By 21:00 he had flown 325 km from his overnight roost and was perched at the northern end of the appropriately named Embalse de la Pena del Aguila. However with a full moon and favourable winds Jules took the opportunity to press on, flying a further 137 km by moonlight before finally settling to roost for the night on a hillside in north-west Andalusia after a day’s flight of 462 km.

At 08:10 next morning he had flown another 9 km south but he didn’t resume migration proper until just before 11:00. He maintained a south-westerly heading and three hours later he was perched beside the Rio Tinto at Heulva, close to one of sites where Scottish ospreys were released as part of the successful osprey translocation project in southern Spain. He continued south-east an hour later, passing over the world famous Coto Donana, before roosting for the night on the banks of the Guadalquivir River after a day’s flight of 168 km.

Jules spent the night of 6th October beside the River Guadalquivir

Next morning Jules followed the river to the coast before turning south and heading towards Cadiz. The fish rich waters of the harbour and surrounding area support an increasing number of wintering ospreys and Jules is likely to have encountered some of them while fishing just to the north of Puerto Real during the afternoon. He spent the night in a forested area 5 km east of Puerto Real having flown 75 km during the course of the day.

When migrating through Spain most migrating raptors head for the short crossing to Morocco across the Strait of Gibraltar, but ospreys are well capable of much longer ocean crossings and after two relatively easy days Jules set off from Cadiz before 06:00 and headed out across the Atlantic. By 07:30 he had already flown 113 km and was flying south-west across the sea at an altitude of 110 m. This initial bearing would have caused him to miss the Morocco coast, but over the course of the next eight hours he flew in a wide arc across the Atlantic at relatively low altitude (all positions less than 90 m) before making landfall at Casablanca at 14:17 local time having flown 398 km across the sea. After crossing Casablanca Jules turned to the south-west and flew another 113 km before eventually settling to roost for the night at 19:09 among olive trees having flown 524 km from Cadiz at an average speed of around 37 km/hour. A superb day of migration.

Jules flew 398 km across the Atlantic between Cadiz and Casablanca

Rather than continuing south on 9th October, Jules headed almost due east. At 13:02 he had reached the coast at Oualidia and then, during the course of the afternoon, completed a loop of some 57 km just to the south. He eventually settled to roost in an area of scattered trees near the village of Abde Laaziz Ben Yeffou having flown 127 km during the course of the day. However his afternoon wanderings means that, in fact, he was just 75 km south-west of his position the previous evening.

Yesterday morning Jules left his roost site at 10:00 and this time headed due north. At 11:10 he had flown 33 km and was at the coast near Ouled Salem. An hour later he was perched on the beach 6 km north-east and he remained there for the rest of the afternoon. With an hour between each GPS fix, there is every chance that Jules caught a fish in the sea at some point during the afternoon and then returned to the same spot on the beach to eat it. Eventually he flew 8 km inland to roost and he was still there at 08:07 this morning.

Jules has spent the last two days on the Morocco coast to the south of Casablanca

It will be very interesting to see how long Jules remains on the Morocco coast. His behaviour over the past two days is typical of an osprey during a stop-over, but there is a slim chance that he could winter here. Most European ospreys either winter in sub-Saharan Africa or in southern Europe but a small number winter in Morocco. The chances are, however, that he’ll continue south across the Sahara in the next few days. Don’t forget that you can check out his latest flight on our interactive map.

Jules’ flight through Spain and Morocco, 4-10 October

Biscay crossing

Having spent 17 days stopping-over a few kilometres to the north-west of the Gulf of Morbihan in Brittany, Jules (Blue JV3) resumed his migration yesterday and flew direct across the Bay of Biscay to Asturias in northern Spain.

Jules spent most of his 17 day stop-over in Brittany to the north-west of Gulf of Morbihan, favouring two locations near Auray (red circles indicate areas with 50% of GPS fixes)

During his stop-over in Brittany Jules spent long periods perched in marshes beside the River Auray

Over the past week Jules had continued to frequent his favoured spots along the River Auray, but when yesterday dawned bright and sunny he took the opportunity to resume his migration. A gap in the satellite data means that we do not know the exact time of his departure from Gulf of Morbihan but it must have been fairly early because at 13:23 local time he had flown 149 km and was flying south-west across the Bay of Biscay at an altitude of 250 m. At 14:35 he was crossing the Saint-Nazarie Canyon where the sea bed drops from a depth of around 100 m to over 4000 m. Interestingly at this point he had climbed to an altitude of 1051 m, suggesting that he was able to exploit some kind of lift; perhaps weak sea thermals which sometimes develop over the Bay of Biscay in autumn. You can read more about this in chapters 2 and 3 of my PhD thesis here. Unfortunately the GPS fixes are not of sufficient temporal resolution to determine whether Jules was soaring over the sea, but the change in altitude certainly suggests it.

Jules climbed to an altitude of 1051 m during his Bay of Biscay crossing, suggesting he may have been able to exploit some form of lift over the sea

Jules was flying with a light east-north-east tailwind and during the course of the afternoon this turned almost due east. Such winds have the potential to cause migrating ospreys to miss the north coast of Spain, but Jules compensated by changing his heading at 15:28 and flying almost due south for 67 km. At 17:12 he turned back to the south-west and continued on a constant bearing to the Spanish coast, flying at altitudes of between 194 m and 76 m. He finally reached land at Aviles in Asturias in northern Spain an hour after sunset at 22:07 local time having flown 515 km from Gulf of Morbihan, 500 km of which was over the Bay of Biscay. Having arrived in the dark he settled to roost in trees on the outskirts of Aviles.

Jules flew 500 km across the Bay of Biscay from Brittany to Asturias

This morning Jules was still at his overnight roost at 08:13 local time but an hour later was perched near Embalse de la Grande. He remained there until at least 11:30, suggesting he may well have caught a fish. By 13:04, the final GPS fix in this batch, he had resumed his migration and was 31 km south of Aviles heading towards the Cantabrian mountains.

You can check out Jules’ latest locations on our interactive map.

Blue JV3 still in Brittany

While Blue DF flies south through Senegal, Blue JV3 is continuing to stop over near the Gulf of Morbihan on the Brittany coast. Blue JV3 refers to the bird’s colour ring on his left leg, but those of you who follow our Facebook page  will know that we asked for suggestions for a name for Blue JV3 to use in our updates. We very much enjoyed reading all your suggestions but in the end by far the most popular name was ‘Jules’ after the French novelist Jules Verne (i.e. JV), most famous for his adventure novels including Around the World in Eighty Days.  It seems fitting therefore that Blue JV3, or Jules as we will now refer to him, is stopping-over in France. Thanks to Janine Pannett for the great suggestion.

Having arrived on Saturday 16th September Jules has spent most of his time in a 40 km² area stretching from the west end of Gulf of Morbihan north to a short section of the River Auray, north of the town of Auray, and then across to his favoured roosting area in the forested banks of the River Bono north of Plougoumelen.

Blue JV3 has tended to favour two areas to the north-west of Gulf of Morbihan since arriving on 16th September. The red shaded areas include 50% of GPS fixes since he arrived

Blue JV3 often roosts beside the River Bono

In recent days Blue JV3 has spent most afternoons beside the River Auray

It will be interesting to see how long Jules remains at Gulf of Morbihan. Another of our satellite tagged birds, Nimrod, stopped-over on Ile d’Oleron, a small island situated just to the south of La Rochelle in autumn 2008, 2009 and 2010. In each year he favoured the same forested area in the south of the island and fished along the coast once or twice a day. In 2010 he spent a total of nineteen days on the island, thereby constituting almost half of the total days (40) it took to migrate to its wintering site in Guinea-Bissau. Don’t forget that you can check out all of Jules’ recent movements on our interactive map.

A Brittany break

After a fast start to his migration at the end of last week Blue JV3 spent much of yesterday at the Gulf of Morbihan on the Brittany coast and was still there at 12:57 local time today.

The previous batch of data had shown that Blue JV3 was just north of Leamington Spa at 08:45 on Saturday morning having left his overnight roost near Leeds soon after first light. Over the course of the next four hours he made fast progress south and at 12:52 was approaching Southampton at an altitude of 698 metres. An hour later he was high (854 m) over western Isle of Wight and he then made a two-an-a-half hour crossing of the English Channel, making landfall to the east of Cherbourg. Once in French airspace he changed his heading to south-west and flew direct across the sea to St-Malo. He eventually settled to roost for the night beside the Rance Estuary, just north of the village of Saint-Suliac at 22:01 local time having flown an impressive 584 km from South Yorkshire.

JV3 roosted beside the Rance Estuary in Brittany on Saturday night

On Sunday morning BLue JV3 had already left his overnight roost at 08:00 and was flying purposefully south-west. Four hours later at midday he was perched on the edge of a forested area to the east of the Gulf of Morbihan having flown 122 km. Interestingly he went no further and instead made only local movements during the course of the afternoon. At 17:18 he was perched in the estuary and was still there an hour later: suggesting he was eating a fish. He then headed off to roost in a wooded area 18 km north-west near the village of Leran.

This morning Blue JV3 flew back to the Gulf of Morbihan and appeared to be fishing at both 10:56 and 11:57, the latter being the last GPS fix in this latest batch of data. This vast natural habour would be an excellent place for a stop-over and it is possible that JV3 will linger here for a few days. His change of track through Brittany certainly indicates that he made a conscious decision to head there. Many ospreys have a favourite stop-over site that they visit on each migration; it seems very likely that this is a place Blue JV3 has visited before.

You can check out Blue JV3’s migration on our interactive map.

Blue JV3 has remained around Gulf of Morbihan since arriving there at lunchtime on Sunday

JV3’s migration 15-18 Sept

Blue JV3 races south

On Wednesday evening this week Roy Dennis and Frank Law caught and satellite tagged another adult male osprey at Rothiemurchus Fishery in Aviemore. Unlike Blue DF who was colour-ringed as a chick, this new male was unringed and, as a result, we can not be sure if he is a breeding male at one of the local nests, or a youngster yet to establish a territory. Nevertheless this is really excellent news because it means we will be able to follow a second male on its autumn migration, and, assuming the bird survives the winter, collect a great deal of valuable information on its movements once it returns to Strathspey next spring.

Roy preparing to release Blue JV3 after tagging him

The new male, which Roy colour ringed as blue/white JV3, had put on a great deal of fat in preparation for migration and, like Blue DF, set off on migration the morning after being tagged. It had an excellent first day of migration, taking advantage of a north-westerly tailwind and flying 420 km before spending the night beside the River Calder between Leeds and Wakefield. We do not know the exact time that Blue JV3 left Starthspey but at 12:28 (BST – times shown on the map are GMT) he was 11 km north of Pitlochry and two hours later he passed over Edinburgh at an altitude of 1240 m. He crossed into English airspace at around 16:00 and then maintained a south-easterly course along the eastern Pennines before skirting around the east side of Leeds and then settling to roost for the night in trees beside the River Calder.

JV3 spent the night of 14th September beside the Rover Calder near Leeds

This morning Blue JV3 resumed his migration at dawn and headed powerfully south passing over Barnsley and then Sheffield before skirting around the west side of Derby at an altitude of 536 metres. By 08:45 he was approaching Leamington Spa had already flown 158 km from his overnight roost. It will be fascinating to see how far south he is when the next batch of data arrives.

You can check out Blue JV3’s migration on our interactive map.

By 08:45 this morning Blue JV3 had already covered 578 km, having left Strathspey just 24 hours earlier.

Our thanks to Julian Orsi and Rothiemurchus Estate for allowing us to catch and tag Blue JV3.