In the post last Friday we wondered if UV would head for Africa by the end of the weekend given favourable weather conditions for crossing the Mediterranean. As of 11.00 UTC on Monday the answer was ‘no’, although he hasn’t done much sitting around in the Alentejo area of Portugal.
UV is behaving quite restlessly for an osprey on a stopover where the norm is ‘catch a meal then loaf around’ – much like activity in wintering grounds. He has been flying for several hours a day and at high altitude at times. On Sunday he probably flew without a break for about 7 hours, although he could have perched briefly early in the period when fixes were about 20 minutes apart. Paul has prepared a graphic showing UV’s altitude profile over Saturday and Sunday.
For nearly 2 hours on Sunday UV was flying at over 3000m ASL. The terrain was mainly only about 150m ASL. This is a view of the area near his highest point.
On Monday morning UV flew from his inland roost to the Atlantic Ocean and on 24 September he spent a few hours at the Rio Corona, his main area on 21 September.
Over the last few days UV has surveyed reservoirs (generally small unnamed ones), the ocean and rivers but mainly from altitude. Why is UV so restless?
Several factors could be at play. The weather is good and for the most part UV has explored areas he wasn’t recorded as visiting in 2014. So he could be filling in gaps in his memory bank whilst visibility allows him to see far and wide. But perhaps there is a more specific purpose.
The region has experienced a very dry summer. Paul’s chart shows the average climate for the region – you can see ‘hot and dry’ is the norm for summer.
In 2016 the temperature has been over 25°F much of the summer and only 9.14 mm of rain has fallen since 1 June. Water levels in many reservoirs are low or very low. See the statistics in this article (translation here courtesy ‘google translate’ 20160905-www-publico-pt-article-on-near-drought-alentejo). In some areas livestock are dying because wells are drying up. UV could be partly motivated by the lack of water in some reservoirs impacting on numbers of available fish and is identifying the best foraging areas – resource-surveying.
We don’t know his reasons, and probably never will, but one thing is certain – he is in ‘explore mode’.