Out and about

It has been nearly two weeks since an update on UV and mostly his activity can be summed up as ‘more of the same’.  Over several consecutive days he can perch for most of the time in one small area then desert what appeared a favourite place. Whilst a few sites – for example the island of Doune Baba Dieye  – are frequent destinations UV has found some new perches recently. Mostly they are in scrub rather than right on the coast.

There are exceptions but UV returns to a roost area at or after sunset – around 19.00 – most days and he is recorded over water just before sunrise (about 07.30) often enough to conclude he usually forages early.

As we’ve said previously UV flies over the river or sea more times each day than is necessary for his energy requirements. The following images show different behaviours.

out to sea

out to sea

These high flying trips out to sea could be looking for shoals of fish. Still the authority, the University of Edinburgh 1982 PhD,  The Wintering Ecology of Ospreys by Yves André Prevost had this to say:- “When foraging 1 to 5 km out at sea, for sardines or flying fish, Ospreys often rose up to an estimated height of 300 m, apparently to locate fish, then came down slowly before diving from up to 100 m.”

But today UV flew about 3.5 km out to sea at relatively low altitudes.

low and slow

low and slow

The fixes were between 5 and 10 minutes apart and UV could have been higher and faster in between them. The group of fixes below 09.34 were mainly 20 minutes apart and he could have been perched somewhere between them, but that area is a favourite hunting ground.

Until recently UV hadn’t been going so far out to sea. We’ll explore why this change may have occurred in a future post.

On 13 January UV displayed more typical behaviour for recent weeks, staying fairly close to shore.

a typical foray over water

a typical foray over water

The yellow-circled fixes appear to show UV perched in water but the sand in all those areas is probably above sea level most if not all of the time nowadays.

Finally, on 16 January UV explored around the National Park area of the Langue de Barbarie, his original ‘home’ there.

a change of mind?

a change of mind?

It looks as though he was heading inland when something attracted his attention – perhaps ospreys or gulls showing interest in a shoal? – and off he went to join in!

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Have wings, will fly

Now we’ve entered a new quarter – and year – Paul has created heatmaps showing UV’s daytime activity from October to December 2016. (UV arrived back from migration on 11 October.) Here is the overview heatmap – the redder the colour on the map the more fixes there are in the area.

courtesy Paul Wildlifewriter

courtesy Paul Wildlifewriter

And here is the same period in 2015.

courtesy Paul Wildlifewriter

courtesy Paul Wildlifewriter

UV was still residing on the southern spit of the Langue de Barbarie for much of October 2015, which explains the ‘hot spot’ near the bottom of the 2015 map.

One image can’t show the whole story and Paul has made a week by week animation of the last quarter of 2016 which is much more revealing.

play

You can see that during November UV started foraging further east – in the river mouth rather than at sea.  In December there are also new areas to the south attracting UV. The reducing fish migration from upstream could be part of the reason for UV’s changes. Satellite imagery shows plankton bloom very near the coast in much of the last two months so fish should still be plentiful in both sea and river estuary.

The last post described how UV’s behaviour appeared unaffected by the Harmattan, the dry and dusty seasonal wind. So far in January the weather has been mainly clear and the tracker battery is now much more fully charged. The plentiful fixes show UV has been even more active than usual including travelling 28 km south for the morning on 5 January.

An early morning trip south

An early morning trip south

Early in the day fixes are 10-40 minutes apart so there isn’t much detail about how UV spent his 4 hours at the southern end of the Langue de Barbarie National Park. The likelihood is he was mainly perched. He spent many hours in that southern patch for a couple of months from late January 2016.

After noon the number of fixes reach a frequency of  1-2 minutes.

More fixes after noon and plenty of activity

More fixes after noon and plenty of activity

UV was airborne for over two hours after heading back north, flying up and down the area from the breach in the Langue de Barbarie to a point opposite Mouit on the mainland, but he wasn’t foraging given most of the altitude readings were over 100m ASL.

But in late afternoon after a period of perching he could well have been hunting in two separate low level flights in the river.

Typical foraging behaviour

Typical foraging behaviour

The previous day, 4 January,  UV had spent over three hours with just a one minute pause flying over the sea and river. His behaviour was similar to that described above – elevation gains then a few foraging level fixes. Was he searching for fish shoals? It doesn’t seem likely as he stayed in a relatively small area, patrolling up and down. He only ‘needs’ one reasonable sized fish a day – although with all his exercise recently he’s burned many calories – so his extended forays may be for no particular reason.

Sometimes UV perches in one spot or a very small area for several hours but lately there are many more ‘busy’ than ‘quiet’ days.

His behaviour on 4 January also serves to highlight something we have noticed before:- previous versions of tracking technology may have given the impression that over-wintering ospreys are more sedentary in their daily routines than is actually the case…

courtesy Paul Wildlifewriter

courtesy Paul Wildlifewriter

courtesy Paul Wildlifewriter

courtesy Paul Wildlifewriter

This pair of images use exactly the same data set, but the first one shows the “old style” activity analysis – where fixes were only available at intervals of three to four hours on any given day. Our 2nd-gen tracking units show how much of this daytime activity was “hidden” in the gaps between positions.

 

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Sand and dust

Since the last update on 24 December UV has continued to travel between various coastal and inland day spots. On 28 December he appeared to be perched in the water, not on the sandy shore, near Lac Guembeul.

UV perches around the shoreline

UV perches around the shoreline

The Google Earth image was taken in early July during the wet season so the water levels will be lower now with more sand exposed.

There have been fewer fixes over the past week – some days only every 20 minutes or so at best – because the tracker’s battery voltage level has been relatively low as this graph by Paul shows.

courtesy Paul Wildlifewriter

courtesy Paul Wildlifewriter

The tiny battery in UV’s tracker unit is charged by solar energy and the charging system is only just enough to maintain battery condition under good direct sunlight. High-altitude dust can attenuate the power of the sun by as much as 20% – even when the sun ‘appears’ to be shining.

The reason for the relatively low voltages is the amount of dust in the atmosphere. At this time of year the Harmattan affects West Africa. Paul has created an animation which shows how the dust eventually reached South America.

The Senegalese authorities issued a ‘red alert’ health warning, a relatively rare event. The fine dust reached ground level as you can see in this powerful photograph by ornithologist Frédéric Bacuez.

The Harmattan (c) Frédéric Bacuez/http://ornithondar.blogspot.com

The Harmattan
(c) Frédéric Bacuez/http://ornithondar.blogspot.com

There are some Osprey photographs in the most recent post on Frédéric’s blog, click the link under the photograph.

Despite the impact on his battery UV’s behaviour seemed unaffected by the week long Harmattan and he was recorded at altitudes over 300m ASL on several days. In this image he was only at foraging level for a couple of fixes during an offshore flight and he flew inland at over 600m ASL.

Was UV foraging briefly?

Was UV foraging briefly?

Today’s data arrived just as this post was being finalised. UV had a busy morning visiting several inland sites but he was at foraging level just offshore for the last few fixes, perhaps finding some lunch!

 

 

 

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A new year dawns

This year four pairs of ospreys bred in Kielder Forest, a significant achievement for the Forestry Commission who have provided the platforms they use for nests.

We have seen a Kielder hatched osprey, Nest 2 Blue 2H, return to his natal grounds which is a major milestone. And for the first time this year Nest 1 Blue 39 was also recorded on a nestcam.

But for many the return of Nest 1 Blue UV – one of the first three chicks to be tracked at Kielder – was more of a highlight. Being able to follow his migrations and life in his wintering grounds in northern Senegal has been a privilege.

This morning he was sitting in the sun on a beach in northern Senegal.

In July he perched by his mother, not that she would recognise him. Here he is, having just landed on the new platform his parents occupied this year. Mum wasn’t happy!

UV lands on his parents' new nest

UV lands on his parents’ new nest

We look forward to 2017, which will begin with more about UV’s recent activity. Our best wishes to readers and thank you for following our ospreys.

 

 

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Where today?

Since the last post about UV he has been a bit of a gadabout. He has visited places such as an irrigation canal and the surrounding land some 11 km east of the centre of his main wintering area.

18 Dec: a few hours inland

18 Dec: a couple of hours inland

He has flown at elevations of over 500m ASL at times – as he did when heading back to the coast from the canal area. On several sorties south around the Langue de Barbarie National Park he has interspersed high and low flying as he did in this typical long flight.

17 Dec: a foray along S spit

17 Dec: a foray along S spit

The flight in the image below around the breach that separates the two parts of the Langue de Barbarie is quite typical of others that last around an hour.

21 Dec: a mixed altitude foray

21 Dec: a mixed altitude foray

UV has also perched in the area around Lac Guembeul and scrub nearer the coast. The last image shows the extent of his range over the last couple of weeks.

UV's recent range

UV’s recent range

Seasons greetings to blog followers from Kielder Ospreys and many thanks for your interest and support.

 

 

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Sand and sky

The last post about UV focussed on his activity south of the area he’s frequented since he returned to Senegal. So you can guess what happened next – he hardly went south again! Until yesterday when he was mainly very high over the Langue de Barbarie National Park area.

UV has had some quiet days when he perches in a very small area for a few hours but there are some intriguing aspects too. In some earlier posts we’ve put images of UV apparently perching on water. On 11 December there are several examples of this where UV is south of the northern section of the Langue de Barbarie.

Wet or dry feet?

Wet or dry feet?

The Google Earth imagery is from May 2016 (that is recent, Kielder Forest is mostly 2009!) and for the most part the sandbanks visible in shallow water will be land now. Paul has calculated that since UV has been in the area (mid October) the north spit has extended by at least 38m. So he is perching on areas that are now land all or most of the time.

UV has foraged near to the shore and also a little way out to sea. Satellite imagery shows plankton bloom on many days now, good feeding for fish.

courtesy Paul wildlifewriter

courtesy Paul Wildlifewriter

Some spots are especially attractive to UV when he is foraging.

A hot spot?

A hot spot?

As you can see in the image he returned to a small area after a foray south. He may have caught a fish but we can’t be sure.

UV is settled in his wintering grounds after his first return to the UK and Kielder. For his followers it has been a wonderful year, seeing his epic Spring migration and nestcam footage of him.

He’s just getting on with life each day and long may that last.

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Sea change

The last few posts about UV described his quite settled existence. He has no fixed routine -spending different amounts of time in several places – but he uses familiar spots and he can sit for hours! Just like most over-wintering ospreys.

On Wednesday UV flew further south than he has done since arriving back in Senegal. At his most southerly point he was offshore near the area that was his home for several months in 2015.

Familiar territory

Familiar territory

Yesterday UV was back there and went further, higher and for longer! He was in the air for around 2.5 hours with a 3 minute break perched on a tree by the river. His maximum altitude was 1036m ASL. Especially when over the river UV could have been hunting. But about 40% of the time he was over 150m ASL, far too high to see fish especially as the water is not clear. Perhaps UV was observing where other birds were hunting given he hasn’t been flying over the area recently. Whatever the reason for his behaviour it is interesting data.

It’s impossible to capture UV’s activity in an image. Paul has spent hours, literally, creating an animation of UV’s outing. UV’s altitude is shown at each point of his journey. Click to follow his route.

play

 

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