7H flies high. UV keeps a low profile

7H

Since the last update 7H has kept to her recent pattern of activity most days. Overall she has visited the gravel extraction area east of the river mouth and the pylons less often. On 7 January she flew from the pylons to a point on the river further upstream than of late, but after a short time circling around she went further towards the estuary.

On the afternoon of 6 January she may have become rather warm when roosting in the poplars. Paul noticed that the tracker temperature reading was up over 40°C; she left the roost and flew very low (between 2-6m altitude) along the river towards the estuary, perhaps to cool off. The tracker temperature dropped to 28.1°C as she started travelling along the river and was at 19.5°C as she returned to roost, so she may have had a brief dip.

7H exhibited intriguing behaviour on 3 and 4 January. Both nights she flew in the early hours about 1 km to a different roost point. The moon would have been bright so visibility would have been OK. There was no weather-related reason to trigger the moves. When still at Kielder she sometimes travelled in the dark but only 100-200m. Since 4 January she has stayed in one place all night.

Here is an image of her overall activity on 6 and 7 January.

7H on 6 and 7 Jan including her visit upstream

7H on 6 and 7 Jan including her visit upstream

The most interesting bits of 7H data were a few fixes on 7 January that appeared to be possibly false altitude readings, although the usual clues to that weren’t there. She had just left the pylons and started gaining height rapidly, flying at about 45 kph. Fixes were every 5-7 mins. She rose from 131m altitude to 503m then 1049m (over the centre of Azemmour) before dropping to 399m as she reached the river. Could this be right? Paul found the answer. There was convective activity in the area and she almost certainly found a thermal to soar on. Paul produced the graphic below.

Using the thermals, 7H gets a real bird's eye view over Azemmour

Using the thermals, 7H gets a real ‘bird’s eye’ view over Azemmour. 

UV

UV’s data hasn’t produced anything ‘extreme’ other than a 6 hour afternoon roost about 1 km inland from the lagoon area. That was on 7 January.  There were even fewer movements the day before.

UV activity on 6 Jan

UV activity on 6 Jan

UV arrived at the bay earlier than many days at some time before 8.58 GMT. When he was stationary on the east side of the lagoons. Fixes were hourly and the next showed him stationary at the west side. The fixes never became very frequent, about every 10-15 minutes apart at best, a sign he wasn’t doing much flying. Late in the day he was moving as the data uploaded and it showed him flying low over the lagoons. He then moved to the ringed area to the west, so perhaps had caught a fish.

On 8 January UV was busier and had quite a few flights around his favourite area.

UV on 8 Jan

UV on 8 Jan

He was particularly active in late afternoon. High tide was at shortly after 14.00; by 16.30 or so it would be receding. But perhaps he had a catch shortly before high tide. He seemed to be hunting just after 13.00.

Is this UV hunting?

Is this UV hunting?

As he flew up and down the stretch of water at speeds of 2-5 kph the tracker temperature reading dropped twice. He didn’t spend long stationary after his time on the water, but went further inland for a longer spell so possibly ‘dealt with’ his catch first before a more leisurely meal. We’ll never know if he did get a fish but it certainly looks like he had his eye on what was in the water.

Both juveniles are behaving in a very settled way – as they should if they are in their wintering grounds. So is it a bit ‘boring’ now? Not at all! GSM trackers produce such large amounts of data most of the time that there are nuggets to find, such as 7H’s thermal soaring. And so much to learn about their ‘routines’.

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

4 Responses to 7H flies high. UV keeps a low profile

  1. Could 7H simply be having fun soaring to over 1000m ?

  2. Peter: A reasonable point. Anyone who watches birds regularly, knows that young raptors, corvids (and many other species) often soar on updraughts or perform aerobatics in good weather for no apparent reason, and it’s hard to escape the conclusion that they do this because they simply enjoy it. However, in this case there MAY be another reason…

    For some time now, I have had the suspicion that there may be another osprey wintering in the Azemmour general area. This is based purely on subtle aspects of 7H’s behaviour – we have no observer on the ground to confirm it or otherwise. It is significant that 7H climbed to an unusual altitude, but also that she altered course SE towards the river upstream of the town and then flew around in various direction on reaching it. This is not one of her usual foraging areas. The behaviour (rapid height gain followed by an apparently random tour out to the edge of her usual “territory”) is consistent with some kind of interaction with another bird – either chasing it, or being chased by it. She was certainly not hunting for fish.

  3. Jillian says:

    Boring is good as long as they both stay well along with all the other ospreys we are following.

  4. Vivien Finn says:

    The trackers are providing scientific data, a valuable asset that enables us to learn about the daily life of each individual bird. Thank you Joanna and Paul for analysing the data and explaining in detail. I look forward to more blogs!

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