One sea, two rivers 500 km apart

In the last few days both 7H and UV have been over the Atlantic, briefly, and both have fished in rivers that flow into that Ocean. But on different continents and about 500 km apart.

UV is still in Portugal and is tending to spend most of his time in trees on the shore of a reservoir. He is just into his third week of stopover. Until Friday he had flown only a few km exploring the area. On Friday he racked up nearly 100 km visiting the ocean and the river Mira. Here is a link to a photo taken very near where UV spent two periods apparently hunting. He arrived at the river just before 11.00 GMT and followed its course. He had been flying at over 1000m not far from the river and dropped height rapidly as he neared it. As he flew along over the water he was mainly below 100m altitude and around 20 kph. After checking the river out he went to the coast, but must have liked what he had seen because he went back to the Mira.

A quick trip to the sea then back to the river Mira

A quick trip to the sea then back to the river Mira

The map below shows the timings of what looked like a catch.

A possible catch for UV

A possible catch for UV

As he was only 6m above the water at 12.19, he may well have caught a fish which he flew SE with initially but then back north and on a tree for 10 minutes. Was he eating the head? He then moved a little bit further north and was stationary for over an hour. Although he then flew along the river for a few more minutes 12.19 (or perhaps during the few minutes he flew south after that) was the only time he could have caught a fish because he did not roost again. Of course, he may not have been successful at all and was just roosting!

UV's exploration of the Mira

UV’s exploration of the Mira

Yesterday he had a rest after those exertions. Although some UK ospreys overwinter in southern Spain, eg Beatrice and Green J, it is some years since UK ospreys were identified wintering in Portugal. Temperatures are typically 10-12 degrees Centigrade between December and March in SW Portugal. A few ospreys do take the risk of a cold spell sending fish to the bottom or warmer waters; the Portuguese website avesdeportugal has some details of where they might be found.

Also on a stopover is 7H, in Morocco. On Tuesday afternoon she was at Oum Er Rbia for what could have been a lunch break. She is still on that river and has been exploring a stretch. Paul Wildlifewriter has just published an analysis of a Finnish tracked juvenile Birgit. She is on a stopover in Holland and is behaving like an adult, with a 20 km corridor to hunt along so she is not restricted to a single food source. 7H is confining herself to about 3 km of river. Even though the fish supply is probably ample, potentially she could attract attention from humans because she must be frequently visible. At least she varying her overnight roosts. Let’s hope she’s read Paul’s piece.

It has been difficult to pick out a hunting trip as clearly as with UV. There are plenty of times 7H is over the river, usually fairly low, and then goes into trees, but all of them won’t be successful catches. It is striking that on the whole she is using small areas of low trees on the east side of the river when she is out during the day, but her overnight roosts have been on the west side.

7H's favourite daytime roost areas

7H’s favourite daytime roost areas

The upside down triangle of massed red dots at the three points were favourite daytime places during her first couple of days near the river. The next image shows her initial roost on 23 September.

7H's first night roost

7H’s first night roost

Lastly, the very small area she is frequenting.

7H's small range on the Oum Rr Rbia

7H’s small range on the Oum Er Rbia

The southernmost fix is by a motorway bridge and she was there on 23 September, her first day. The exploratory loop to the west was a short trip on 26 September.

Hopefully she will soon feel able to continue her migration after this bit of R&R.

With thanks to Paul, Tiger and Sue especially for useful discussion and links to items about ospreys and Portugal particularly.

And finally, there is still no data for VV, last heard from on the edge of the Atlas Mountains on 11 September. She almost certainly has not survived although the reason is not apparent. Even with limited mobile phone masts in some areas she should have reached Senegal and better coverage several days ago. So sad, she had been migrating safely and without over strenuous days. She will never be forgotten.

This entry was posted in Blue 7H, Blue UV, Blue VV, Migration, Osprey updates and tagged . Bookmark the permalink.

5 Responses to One sea, two rivers 500 km apart

  1. Is there really no hope for VV? This is so sad to all who have followed her throughout her short life.

  2. joannadailey says:

    It’s very unlikely that she has survived, ViV. The tracker was behaving normally. She was going into an area where we knew there would be silence because of the lack of mobile phone masts which transmit the data. It normally takes about 6 days for ospreys to get back into communication with that type of tracker. We have heard nothing since 11 September. With no data confirming what happened to her arguably she is ‘missing in action’, but realistically there is little chance she is alive.

  3. Vivien Finn says:

    Truly sorry that there has been no news of VV for this length of time. It is hard to accept that she is unlikely to be alive, but without any evidence to confirm otherwise we must be realistic.For you Joanna it is even harder, so very sorry and sad too, VV was doing so well.

  4. Jillian says:

    So pleased to hear that 2 out of 3 are do
    ing so well. Very sad if VV has not survived. I know you will let us know if you get anything from her tracker again.

  5. Joyce Rawlings says:

    RIP VV


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