UV: his first couple of months in wintering grounds

UV arrived back in his wintering area on 15 October 2017. As in 2016, he had several exploratory flights further afield in the first few days after his return. Since then, he has been within his usual broad range. You can see the extent of it in Paul’s animation of UV’s flying fixes.

On many days UV travels well outside his core area of about 28 km². His furthest excursions are NE, to wetlands south of the Ngalam river (c14 km from the coast) and an irrigation canal running south from it (c11.5 km). Why does he visit these places? We wish we could give a definitive answer!

The reason is not weather related. Perhaps on some visits UV bathes in the fresh water, but there are fresh water lagoons in/near his core zone. Often, UV doesn’t stop, but overflies the area(s) then heads back to the coast. He sometimes flies high – over 500m ASL – either on the way there or back, occasionally in both directions. But in the wetland/canal region, he is usually recorded at altitudes of under 100m ASL.

The limited amount of information available from satellite tracked ospreys suggests UV roams more than most overwintering ospreys. One osprey who overwinters about 60 km south of UV, Rutland Osprey Project‘s 30(05), has a very small area, as you can see if you click on her name to open the link. She is a 12 year old female, but males can also spend virtually all their time within a few km². FR3, a 2015 male from Loch of the Lowes, is one such osprey, although as mentioned in his link, he had taken occasional jaunts. (His GPS transmitter ceased sending data this summer, but twice recently he has been seen in the centre of his wintering grounds.)

In contrast, an adult male who travels 16 km most days from roost to foraging grounds is Blue JV3/Jules, fitted with a GSM/GPS transmitter by the Roy Dennis Highland Foundation in 2017. There is so much still to learn about ospreys’ behaviour.

Close to UV’s core area, his data reveals interesting activity. Referring back to the animation, the land immediately north of the core – the northern part of the Langue de Barbarie – was a destination of choice in winter 2015-16, less so winter 2016-17 as agricultural activity increased there. The animation shows several visits to North spit from October to 2 December 2017 – then none to 1 January 2018. Jean-Marie Dupart told us that there was more fishing activity in early December – fishermen set up temporary camps and head out to sea in their pirogues, often leaving some people on the beach. UV spent over 3.5 hours on North spit on 2 January, so there can have been minimal human activity that day.

a quiet afternoon on N spit beach

The Google Earth image is from April 2017. The first perching point is no longer on a sandbank off a short ‘finger’, as this photo taken from 35,000 ft in December 2017 shows.

enhancement courtesy Paul McMichael
(c) Joanna Dailey

That ‘finger’ is more than double the length now.

Finally, we haven’t received any data from 7L/Aln since 25 December. As we’ve said, cell towers are only present in the very south of the Banc d’Arguin National Park, and Aln is in the far north. She hasn’t had an incentive to travel any distance in recent days, as this graphic shows.

courtesy Paul McMichael

The concentrations just south of Aln’s area of Mauritania were particularly dense on 1 January. In Senegal, there have been several health alerts in the past three weeks or so about poor air quality, as usually happens at this time of year. Perhaps as the Harmattan season draws to a close, Aln will explore further afield again.

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A great start to the New Year!

Jean-Marie Dupart was out photographing ospreys this morning, and he found UV enjoying brunch on the same Baobab as on 22 December, when Jean-Marie photographed him flying away. Here is a lovely sequence of Jean-Marie’s photos of a well-fed looking UV!

(c) Jean-Marie Dupart

(c) Jean-Marie Dupart

(c) Jean-Marie Dupart

(c) Jean-Marie Dupart

(c) Jean-Marie Dupart

Many thanks to Jean-Marie for sharing his special photos with us.

The data from UV’s GSM/GPS tracker shows that recently, UV hasn’t used that tree as much as several other inland perches. A very good start to the New Year for Jean-Marie to find him there, and in ‘pose’ mode!

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Best ever Christmas present

Just over a week ago, Aln’s GSM/GPS transmitter sent a limited amount of data from near the northern end of the Banc d’Arguin National Park in Mauritania. There are very few GSM masts in the area. Today, Aln was within range of one – at the southern end of her range on 16 December.

courtesy Paul McMichael

Aln was at the northern end of today’s fixes when the data was transmitted. This is possibly the southern extreme for sending data. As on 16 December, there were only new points for just a few hours. But so welcome! The next image shows Aln to the south early in the day, then travelling northwards.

a lazy morning before heading north

The weather for both UV and Aln has been challenging over the past few days, with the Harmattan bringing Saharan dust from the east – Jean-Marie’s photo of UV in the last post gave an idea how much visibility is reduced. This graphic shows large amounts of dust well offshore.

courtesy Paul McMichael

There should be clearer skies from tomorrow.

UV and Aln are about 540 km apart. Will Aln move south at some point? Recent poor visibility wouldn’t have encouraged her to leave the Banc d’Arguin. Time will tell, but she is in a known good wintering area, so Mauritania may be her home for the next 16 months or more.

Here are our two tagged Kielder ospreys this afternoon. Oblivious to Christmas!

Christmas in West Africa

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UV update – with his photo, taken today!

Latterly, UV has been spending much of his time in a small area near Pilote Barre lighthouse in northern Senegal. Our friend Jean-Marie Dupart has made several visits to the area over the last few days. This morning, he saw UV!

UV and a small fish
(c) Jean-Marie Dupart

There is a lot of Saharan dust being carried out to sea by strong easterly winds at the moment, so UV has quite a golden glow! It is wonderful for us at Kielder Ospreys to see a photo of him, our thanks to Jean-Marie. He has taken some photos of the area, too. Here is the beach near the lighthouse.

Pilote Barre and the beach
(c) Jean-Marie Dupart

On Google Earth, it often looks as though UV is sitting offshore from Pilote Barre. This is one of his recent foraging trips. Pilote Barre is just above the top of the image.

After flying around, UV homes in on a ‘hotspot’

Another image shows over 24 hours of UV’s activity in the area. The stars are all perches.

not sandbar perches

What looks like a group of sandbar perches for UV is actually now part of the beach top left of the first image. Jean-Marie estimates it has extended c500m since the Google Earth photo was taken in April 2017, and has sketched the changes. The photo icon is on Pilote Barre’s site, centre of the image.

courtesy Jean-Marie Dupart and Google Earth

The current is depositing sand in the northern part of the area shown on the map, but tides are destroying the end of the Langue de Barbarie National Park (Jean-Marie’s land reduction at the bottom of the image).  This is a consequence of cutting a breach through the Langue de Barbarie in 2003 to reduce the risk of flooding for the city of Saint-Louis.

Here are a couple more photos from Jean-Marie.

looking south towards the Langue de Barbarie National Park from Pilote Barre
(c) Jean-Marie Dupart

a sandbar off Pilote Barre
(c) Jean-Marie Dupart

a lovely setting sun
(c) Jean-Marie Dupart

It is always special to see up to date photos of overwintering areas, and even more so to see the osprey in question. Many thanks to Jean-Marie for his dedication.

Finally, there hasn’t been any more data from Aln. This is not surprising as in the Banc d’Arguin National Park there are only 2 GSM towers. Both are in the far south, over 90 km from Aln’s location on 16 December. Those few so important fixes may be all we receive for many months.

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Christmas comes early – Aln is safe

Until late yesterday afternoon, we lacked any knowledge of Aln’s whereabouts since she was in the foothills of the High Atlas Mountains early on 9 November.

We have now received a precious 100 data points, all from yesterday. Although we don’t know her route, Aln appears to be well and is living on the coast in Mauritania. For now!

from the mountains to the ocean

courtesy Paul McMichael

As Paul’s label states, Aln is in the very far north of the Banc d’Arguin National Park, and was also north of the Park boundary yesterday. We’ve mentioned the Banc d’Arguin before. This year, when he reached there, UV changed from the direct migration mode he’d deployed over the desert to a strategy more akin to fly-and-forage migration. He took several days to return to the Langue de Barbarie.

Analysing Aln’s new data suggests she has been in the area for a while. She had roosted a short way inland then went to the coast, flew north, and was returning south on the last fix late afternoon. The ‘panels to earth’ in Paul’s graphic above show she was flying high at times. The next image shows her travelling across the desert at much greater elevation than most of her flying offshore and along the coast.

meandering around the shoreline, high over the land

On her trip north, Aln flew low and slow.

about 5 km offshore at furthest points as Aln flew north

She perched for varying lengths of time during the day. In the image above, Aln sat from 11.54-13.35 – her longest recorded period of perching – at the edge of the ocean at her most northerly point of the day.

All these behaviours are characteristic of an osprey in their wintering grounds, or at a staging post.

We may be fortunate and receive some more data over the next few days, however it is clear that cell tower coverage is not comprehensive. Those 100 or so fixes have given reassurance that Aln is safe, for now.

A few 100 km to the south, UV was also flying high – over 500m ASL – when his data arrived this afternoon. He hasn’t spent much time on the North spit of the Langue de Barbarie lately. There’ll be a short post about his activity towards the end of the week.

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UV update

UV received a few brief mentions in early November – he was mainly loafing in his wintering grounds in coastal northern Senegal. Since then, he has had a couple of trips inland to a canal he visits occasionally. He turned round and flew back to the coast after, at most, a few minutes there. On one journey he was flying at over 1000m ASL for several fixes, and over 400m ASL for much of his excursion. Some high flying offshore has been a feature of his recent days.

low over the popular foraging area after a high approach

The cluster of fixes near the 13.45 dot is over an area UV has favoured of late. The water will be shallow there – you can see sandbars on the Google Earth image above – so fish should be easily spotted. But UV has also been making repeated trips to just past a shelf in the Atlantic Ocean.

offshore, but back to the ‘hotspot’

Where the shallow water meets deeper ocean the ample food sources at such current margins are likely to support plenty of fish. UV may be watching birds, or even marine creatures, foraging there. But, for the most part, he seems to catch his own meals nearer shore.

UV may have changed his preferred foraging area over the last couple of days. A ‘health warning’ first. There are few fixes until about noon at the moment. The weather has been partly cloudy and UV’s relative inactivity also reduces the frequency of ‘pings’ to satellites. He could have exhibited similar behaviour to that shown in the above images during the mornings. But he has concentrated on the river in the afternoons.

a sandbar can be seen where UV perched

The satellite imagery on Apple maps is slightly more recent than the April 2017 Google Earth pane.

courtesy Apple maps

UV had been foraging just below the northern part of the Langue de Barbarie (left on the image) until 23 November. Yesterday, as on 23 November, he was attracted to the area arrowed. This photograph shows the view of the river from the edge of the trees on the island of Doune Baba Dieye.

February 2017
(c) Joanna Dailey

UV would have been over the river at the left hand edge of the photo.

Unless there is news meriting a post, there will be one or two updates a month over the winter.

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Aln

There has been no new data from Aln’s GSM/GPS transmitter since early on Thursday 9 November, when she was setting out to cross the High Atlas Mountains.

Her southerly course was well to the east of most migration flyways. The image below shows the route taken by UV, now quite experienced. Many ospreys use a similar route across Western Sahara.

Aln’s last roost shown in red, course likely to take her to near or E of the circled area

There will be few cell towers along Aln’s expected path far inland – if she negotiated the High Atlas range successfully. Several days of no data were likely, but by now we should have received some information, even if only a partial upload.

Very sadly, absence of data suggests Aln has not survived. Let’s hope she proves that fear wrong. Ospreys so often amaze us.

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