UV wings it!

When the last update was written UV had just returned to the lagoon area on the northern end of the Gulf of Cintra. And that is where he still is when the last data was received at lunchtime today. He has mainly just loafed by the lagoons or a bit inland, but there are some more interesting aspects to the last few days.

On 23 December he was quite late establishing an overnight roost area, not arriving there until after sunset. On 24 December he chose another inland spot, then a third on 25 December and the last one has been his overnight spot ever since. Generally he is off his roost fairly near sunrise but on 27 December he wasn’t recorded away from the desert until 13.34, when he was speeding towards the water.

And speeding is the right word!  Paul measured his speed-over-ground through three points 13:46:38-13:48:34 as an average of 19.28 meters/sec. (69.4 km/h) with a peak recorded speed of 24.6 meters/sec (88.8 km/h). There was a prevailing wind helping him but all the same he was in a hurry for a late brunch! He was flying at altitude too as the image below shows.

UV flies high and at speed to get to his food source

UV flies high and at speed to get to his food source

On 24 and 25 December UV was very focussed on the lagoons in the curve of the bay as the next graphic illustrates.

UV on 24 and 25 December in the lagoon area

UV on 24 and 25 December in the lagoon area

You can see he had several lengthy roosts just inland after trips onto the water. Presumably at least one was to eat a fish. Perhaps hunting wasn’t easy because high tide on those days was around 14.00 to 14.45 GMT; low tide on both was before he arrived at the water.

The next day (image below) he scarcely visited the lagoon area at all as far as the data reveals, although that early morning roost just north of them would fit with a lagoon catch as low tide was at about 9.15. Fixes are only about every 30 minutes until late morning.

UV on 26 December

UV on 26 December

The top image shows a more balanced range of ocean and bay hunting on 27 December, as did the data for 28 December.

UV on 28 December

UV on 28 December

The last day and a half has been mainly bay living for young UV, although he was flying up the coast on the last fix at soon after 13.00 today.

The graphic below shows the detail of one of his roosts yesterday.

UV on 29 Dec

UV on 29 Dec

Low tide was at about 12.20 and UV would not have been in the water initially, but maybe he had moved away east at 13.44 because his talons were getting washed!

UV is in a place with some fresh water – the sebkhets – for bathing and sheltered lagoons and the ocean for hunting. There is unlikely to be much if any human presence to disturb him. Should he stay or should he head south to better known wintering quarters for UK ospreys?

Experienced adults tend to take the prime areas at coastal estuaries in Senegal and The Gambia with most juveniles further inland. By now the tributaries of the big rivers eg the Senegal are drying up. Most of the fish in Senegal’s irrigation canals will have been harvested. The juveniles may be finding life a bit tougher than when they arrived, but they now have their territories and will have found the best hunting spots so a new osprey would be at a disadvantage inland as well as on the coast. Past data from other tracked juveniles has shown they sometimes move to the coast as the adults head for Europe in February and prime territory is vacated, but that is a long time away. So on balance perhaps UV is in a good – albeit unusual – place.

Thanks to Paul for stimulating discussion on the pros and cons of moving on. And for those of you interested in reading more on speed, here is Paul’s latest research on the subject.

This entry was posted in Blue UV, Migration, Osprey updates and tagged , . Bookmark the permalink.

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