UV’s Little Island – by Paul Wildlifewriter

Since late October and November, we’ve seen UV adopt a new location on the Senegal coast where he spends many happy hours indulging in a young adult osprey’s favourite activity… inactivity. This animation sequence covering the last three weeks (only) shows his perching [red] and flying [orange] positions through each day. The scale is 1:12000


The “focus” location appears to be a small island on the Langue de Barbarie. Six years ago, this low-lying bubble of sand didn’t exist. Six years before that, it DID exist – but it wasn’t an island.

There’s a reason for all this…

The course of the Senegal River as it approaches the sea has always been variable and its hydrology is unstable. Unlike most major river deltas, the Senegal encounters a strong south-going current where it meets the Atlantic Ocean and this means that a sand spit – the Langue de Barbarie – has formed at this point, forcing the mouth of the river to migrate down the coast. In the geological past, tidal effects and the accumulation of silt meant that the estuary could no longer accommodate the peak river flow during the rainy season. The land behind the river became flooded to a greater extent each year, until a breach in the Langue appeared. There is evidence from drilled core samples that this cycle has happened many times over the last 380,000 years.

In 2003, the city of St Louis/Ndar was threatened with such flooding and the Senegalese authorities decided to give Nature a hand by creating a relieving breach themselves. They dug a channel through the Langue about seven kilometres south of the city centre, allowing the pent-up waters of the river to escape to the sea.

Image credit: Durand, Anselme and Thomas, article in Cybergeo 2010

Image credit: Durand, Anselme and Thomas,
article in Cybergeo 2010

The plan worked and St Louis/Ndar was saved – but the power of the river and the ocean had been underestimated…

The gap in the Langue got wider. The next year, it was wider still. Salt water from the sea contaminated the low-lying fields around Gandiol. People lost their farms and their homes. Some of Senegal’s most popular tourist hotels were inundated and, inland, whole forests died. It was an environmental disaster.

Since then, the coastal erosion of the southern Langue has continued and its pace is accelerating. This sequence of Google Earth images shows that the rate of erosion between 2004 and 2008 was around 300m per year. From 2011 to 2015 it was over 1200m per year and still rising. Some attempts have been made to construct erosion defences at vulnerable spots – but this hydrological genie will not go back in the bottle until his work is complete…

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…because as the Langue de Barbarie is destroyed towards the south, the river and the sea are rebuilding it in the north. It is a process that will take many hundreds or even thousands of years but, in the meantime, some of the local wildlife is already taking advantage. Coastal vegetation is starting to re-establish. Ospreys are adaptable birds and UV has found that the newly-formed little island is an ideal spot for sunning himself, safe from predators and human disturbance. Reports suggest that many other ospreys are still occupying the area: the terrain may have changed but they have worked out how to turn these changes to their own purposes. It may be that the altered river course concentrates fish movements into a smaller area, making hunting easier.

UV at 10.42 on 20 October (c) Rafa Benjumea

UV at 10.42 on 20 October
(c) Rafa Benjumea

As west Africa moves from wet to dry season this winter, we will be watching UV’s activity with keen interest to see what he makes of it.

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UV – the first report of a sighting since he left Kielder!

Although we know from his tracker that UV is in Northern Senegal we have never received any reports that he has been seen there – nor previously at various of his stopovers or on migration.

So it is thrilling for us that UV has been seen flying along the lagoon near his original area on the southern part of the Langue de Barbarie National Park.

The Project Tougoupeul is conducting important work monitoring bird populations in the area. Two Spanish biologists from Ecotono Birding Sevilla are assisting and have counted numerous Ospreys already. There are some great photos on their site.

We have been in touch with them about UV and yesterday they spotted him foraging near the Zebrabar, travelling north. They could see the tracker clearly through a scope. When we checked the times of their sighting against UV’s data there is no doubt it was him. Here is a photo from Rafa – even at distance the antenna and tracker are visible.

UV at 10.42 on 20 October (c) Rafa Benjumea

UV at 10.42 on 20 November
(c) Rafa Benjumea

In this graphic by Paul the likely route between fixes has been added.

20 November: UV's fixes matched to Rafa's information

20 November: UV’s fixes matched to Rafa’s information

And lastly an image of UV’s route just 3 days earlier on 17 November.

17 November: UV crosses the lagoon near Zebrabar

17 November: UV crosses the lagoon near Zebrabar

We are so grateful to Rafa and his colleague for their efforts, and hope this isn’t the last time they see UV!

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Nest 1 and Nest 2 intruder Blue BV: background details

Blue BV, who had intruded in August 2014 on Nest 1, paid several visits to that nest and one to Nest 2 in 2015. Here he is on Nest 1, with another intruder, Blue 69 in the background.

Blue BV looks up at Blue 2H flying overhead (c) Forestry Commission England

Blue BV looks up at Blue 2H flying overhead
(c) Forestry Commission England

Ian Francis of the Grampian Ringing Group has told us that Blue BV was one of a brood of two from a long established nest in Donside, Aberdeenshire. He hatched in 2011, so was three years old when first seen at Kielder last year.

The first time he was identified in 2015 was on 30 July when he landed on Nest 2 and started eating a fish that juvenile Blue VM had been tucking into.

After standing beside Blue BV in the hope of being fed VM gave up and flew off. Sibling Blue VS arrived a few minutes later and took the fish off Blue BV.

VS takes the trout from Blue BV (c) Forestry Commission England

VS takes the trout from Blue BV
(c) Forestry Commission England

Two days later Blue BV landed on Nest 1.

He ws soon joined by Blue 69 and then a little later Blue 2H, the 2012 Nest 2 offspring, also landed. Three males on YA’s nest but no sign of him!

Blue BV was seen again on Nest 1 later in the month. He seems to like the area – and the trout – so perhaps we’ll see him again next year.

Our thanks to Ian for sharing the details about him.

Ten ringed intruders were identified from the nestcams at Kielder in 2015 and there were at least a couple of unringed Ospreys in the area.

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UV: semi-settled!

After several weeks of ‘no fixed abode’, from the start of the 3rd week in October UV appeared to have chosen the northern part of the Langue de Barbarie to while away his days. There hasn’t been an apparently significant shift in behaviour so far during November but UV isn’t as settled into a daily routine as he was in the summer on the southern part of the Langue de Barbarie.

Occasionally UV only spends a few hours on the north spit, staying at his inland roost area until late morning or visiting the Lake Guembeul area also. Although on 13 November he may not to have perched on the north spit at all; there were infrequent fixes because of cloudy weather. There are a couple of intriguing aspects to his behaviour – but there are more questions than definitive answers.

Has UV shown no interest in the southern Langue de Barbarie? Initially in November the answer seemed definitely not. This image is his activity from 1-8 November.

1-8 Nov: UV's range

1-8 Nov: UV’s range

The orange patch on the southern spit is UV’s original territory from the end of April through to September. UV could have visited there between fixes but as you can see there is no evidence.

However since 9 November UV has often travelled north via the lagoon between the mainland and the southern spit and once he was over the sea beyond. The earlier UV sets out for his daytime destination the less fixes there are – often only one every 40 minutes until after 10.00 – therefore firm conclusions cannot  be drawn. Most days now there is at least one fix in the lagoon area but it is usually above foraging height, so is he checking out his ‘old’ area? In this image of 13 November the fix is very near that orange patch.

13 Nov: an inland day for UV

13 Nov: an inland day for UV

Is UV able to forage successfully near the north spit? In the top image UV’s foraging some distance offshore – up to 6 km and frequently 2 km – stands out. This graphic by Paul shows the silt plume flowing out to sea and being taken slightly south by the current.

9 Nov: when visible the plume has mainly flowed slightly southwards

9 Nov: when visible the plume has mainly flowed slightly southwards

Mostly UV is over the sea where the water is discoloured. Sometimes he spends 30 minutes or so on a hunting trip.

5 November: 14.50-15.20 hunting trip

5 November: 14.50-15.20 hunting trip

On this and most occasions UV is mainly at a level he should be able to see fish – but can he in the murky water? Sometimes the temperature of the tracker dips several degrees suggesting he may have been immersed. Quite often he spends some time near Lake Guembeul (for example on 13 November, image above)  and he may have more success there. Or in the flooded wetland area near his roost, although it will be starting to dry out now.

When UV is travelling between his roost area and other places he is often under 100m ASL, but sometimes he has a good look around from a rather higher elevation. On 6 November he flew at over 200m ASL during his travel to and from roost. His highest point in a fix was 661m on his return trip. A good reason for one of Paul’s elevation graphics!

6 Feb: flying high

6 Feb: flying high

Yesterday’s weather satellite image showed the silt outflow has lessened considerably. It’ll be interesting to monitor what effect that has on UV.

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UV in October

The last update on UV said there would be a summary of his activity in October with an animation by Paul. Here is UV’s month. There was quite a bit of variety.


UV has a tendency to laze on the beach many days, so not a lot of animation from him on those ones! A powerful tool this particular month is a ‘week by week’ slide show. Here are Paul’s graphics.

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Stating the obvious, from his initial exploratory phase at the start of the month UV has refined his range to focus his daytime activity almost exclusively on the northern spit of the Langue de Barbarie.

From 10-22 October he was tending to spend three or four days either on the north or the south spit but since later on 22 October there is no data showing him perched on the southern part. So that’s where he’ll be when the next set of data comes in!

The rainy season is ending so there are more weather satellite images without cloud obscuring the area. The first clear image after 17 October (when UV was on the northern spit and the silt plume flowed south of the river mouth) was 24 October. Another graphic by Paul.

24 October: UV's range in comparison with the silt outflow

24 October: UV’s range in comparison with the silt outflow

Since then whenever the outflow has been visible the current has been dispersing it southwards. So UV is spending his days in the area of better visibility – although he could easily fly there within minutes if he kept to the southern spit.

A local weather warning of “hazardous swells” was issued covering 29 and 30 October. There were high tides forecast then although these are common several times a year. UV’s behaviour was interesting on those two days.

29 October:

29 October: UV over 3 km offshore

On 29 October UV was over three km off shore during two afternoon foraging trips to sea. Usually he stays close to the shore on the north spit. And that was where he was on an offshore flight before noon, when the warning came into force.

Then on 30 October…

30 October: UV mainly inland

30 October: UV inland

Although there were no fixes of UV offshore he may have foraged early when there are longer intervals between fixes. His behaviour on those two days was consistent with difficulty foraging offshore but it is impossible to be sure there is a causal link.

Many thanks to Paul for creating both the animation and something of an overload of graphics for this post.

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VY and UV update

First, thanks to everyone who has given support here and elsewhere following the loss of 7H. This post was in preparation when our focus had to shift to 7H’s data.

The last post about VY described her settling into a new area upriver on the Casamance after her exploration in Guinea Bissau. From 8 to 18 October her activity ranged along a 10 km stretch of coast and occasionally inland a few km.

8-18 October: VY's range

8-18 October: VY’s range

We haven’t received data since 18 October when VY was in quite a few coastal and inland locations.

18 October: VY to 15.00

18 October: VY range to 15.00, the yellow marker

Analysis of the tracker telemetry and her behaviour didn’t indicate anything untoward and the likeliest explanation is that as the weather improved she decided to travel further afield and out of range of cell towers again. Even just a few km north, south or east there is less coverage.

 Obviously we had hoped contact would be re-established after a few days – as happened in late September – but there has been nothing so far. There will be an update when there is news.

Meanwhile, UV has not returned to his original territory on the Langue de Barbarie. He spent the first few days after the last update (17 October) on the Langue south of that area but since 22 October he has been hunting and perching on the north spit. Here is a close up of a typical day there. 

Lots of relaxing on the beach!

28 October: UV on the north spit

28 October: UV on the north spit

He roosts inland, alternating between a wooded area by a tributary of the Senegal River and the marshy land east of the Langue de Barbarie that has been part of his range during the wet season. 26 October was a rather damp day as the rainy season came to an end. This is UV’s activity that day on a graphic by Paul.

26 October: a wet day

26 October: a wet day

There was an early fix offshore so he probably caught a fish and went back inland for the day.

Thanks to the owners of the Zebrabar (what a great observation tower) on the mainland opposite UV’s ‘old’ area we know a “big raft” was floating there but it only arrived on 17 October, well after UV deserted his stretch of mangroves and beach. So we still don’t know why he has changed his behaviour.

We will summarise UV’s October with one of Paul’s ‘day by day’ animations next week.

A final UV related matter. In the recent Rutland Water Project post about 30(05) she made an unusual (for her) round trip 36 miles inland. Regular readers may recall UV spent several months a short distance down the coast from 30(05). During that time he spent many a day at the Darou Khoudoss phosphate mine, 30(05)’s destination! This image is a close up of UV in the area on 12 February with 30(05)’s recent position.

The phosphate mine, a draw for Ospreys

The phosphate mine, a draw for Ospreys


Posted in Abroad, Blue UV, Blue VY, Migration, Osprey updates | Tagged , | 2 Comments

7H: Just a few of so many memories

7H was the youngest chick on Nest 2. She had hatched by the time the nestcam stream started on 7 June. This was our first view of her, peeping out at the world as her mother stood up.

7H at a few hours old (c) Forestry Commission

7H at a few hours old
(c) Forestry Commission England

From day 1 she proved she would not be overshadowed by her older siblings as she squeezed between them for a mouthful. Aged one week  she was experienced in getting her fair share of fish. If not more!

7H at one week old stretches in front of her older sister and gets her reward (c) Forestry Commission England

7H at one week old stretches in front of her older sister and gets her reward
(c) Forestry Commission England

She mainly kept a low profile if one of her sisters decided to show she was top chick.

7H lies low, literally (c) Forestry Commission England

7H lies low, literally
(c) Forestry Commission England

At a month old 7H was flapping her wings as vigorously as her siblings.

7H at a month old (c) Forestry Commission England

7H at a month old
(c) Forestry Commission England

Her feisty attitude made her first choice to be tracked; usually the eldest chick is selected subject to weight and health. 7H was very pale chested from an early stage and also looked quite small so was possibly male. But she weighed the same as one sister and more than the other. Clearly all muscle! Here she is at ringing.

7H at ringing (c) Joanna Dailey

7H at ringing
(c) Joanna Dailey

Another memorable event was fledging. On 29 July 9H looked likely to take the plunge and 7H had been studying her with interest. When 9H stopped helicoptering for a moment 7H went to the top edge of the nest, so no good images, and took off. She returned to the nest to supervise 9H’s fledge a little later.

7H watches 9H just before deciding to upstage her and go first (c) Forestry Commission England

7H checks 9H’s technique
(c) Forestry Commission England

In the next few weeks 7H gained flying experience around the nest area and a bit further afield. Remarkably the detailed tracking data never recorded her over Kielder Water, she preferred exploring burns and a river nearer the nest. Like all Ospreys  7H concentrated on feeding up for her migration.

7H collects a take away (c) Forestry Commission England

7H collects a take away
(c) Forestry Commission England

She was the last youngster to leave, on 7 September. Any further knowledge of her activity would come from the tracking data and possibly sightings. Paul has written a blog outlining the significant contribution 7H’s data has made to knowledge of Ospreys; in this post there are just a few highlights from a human interest perspective.

The first was her flight from the UK to mainland Europe, which began in the Scillies and took her over the Bay of Biscay. As sundown approached 7H decided to roost on an island which, of course, was actually a ship. Then she moved to a better ‘island’. Waking the next morning she found herself quite near the English Channel and had to travel almost as far again as the previous day, and then further, to reach Spain. She became a talked about Osprey as a result of this ‘adventure’.

7H on a short journey by ship in the Bay of Biscay before her overnight one.

7H on a short journey by ship in the Bay of Biscay before her overnight one

She migrated through Spain and Portugal leaving from the far SW for her next sea journey to Africa (which included a short stop on a boat near the Moroccan coast); we expected this to be the start of a route south of the Sahara. But 7H became the first recorded UK Osprey to overwinter in Morocco. She chose the second largest river in Morocco, the Oum Er Rbia, for her territory.

Throughout her time there she had quite a large range which was at its greatest extent in the few weeks before her death. She often flew fairly high, sometimes very high eg over 500m ASL, apparently enjoying the thermals. She had favourite roosts which included a number of transmission towers and pylons – a very different environment to Kielder but providing her with plenty of commanding views.

7H movement after returning to Azemmour

Some of 7H’s favourite pylons

In late January 2015 data ceased. Nothing had suggested 7H had a problem but so often – as with her this week – there is no warning of trouble. Thanks to Pip and Vic making a diversion during their February holiday 7H was discovered in one of her favourite spots and further investigation by the tracker company resulted in restored transmissions. We have learned so much more in those extra months.

The only known photographs of 7H in her wintering grounds are from that February trip. Here she is hunting along the river. How she should be remembered – doing what comes naturally.

7H foraging (c) Vic Paine

7H foraging
(c) Vic Paine


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