After several weeks of ‘no fixed abode’, from the start of the 3rd week in October UV appeared to have chosen the northern part of the Langue de Barbarie to while away his days. There hasn’t been an apparently significant shift in behaviour so far during November but UV isn’t as settled into a daily routine as he was in the summer on the southern part of the Langue de Barbarie.
Occasionally UV only spends a few hours on the north spit, staying at his inland roost area until late morning or visiting the Lake Guembeul area also. Although on 13 November he may not to have perched on the north spit at all; there were infrequent fixes because of cloudy weather. There are a couple of intriguing aspects to his behaviour – but there are more questions than definitive answers.
Has UV shown no interest in the southern Langue de Barbarie? Initially in November the answer seemed definitely not. This image is his activity from 1-8 November.
The orange patch on the southern spit is UV’s original territory from the end of April through to September. UV could have visited there between fixes but as you can see there is no evidence.
However since 9 November UV has often travelled north via the lagoon between the mainland and the southern spit and once he was over the sea beyond. The earlier UV sets out for his daytime destination the less fixes there are – often only one every 40 minutes until after 10.00 – therefore firm conclusions cannot be drawn. Most days now there is at least one fix in the lagoon area but it is usually above foraging height, so is he checking out his ‘old’ area? In this image of 13 November the fix is very near that orange patch.
Is UV able to forage successfully near the north spit? In the top image UV’s foraging some distance offshore – up to 6 km and frequently 2 km – stands out. This graphic by Paul shows the silt plume flowing out to sea and being taken slightly south by the current.
Mostly UV is over the sea where the water is discoloured. Sometimes he spends 30 minutes or so on a hunting trip.
On this and most occasions UV is mainly at a level he should be able to see fish – but can he in the murky water? Sometimes the temperature of the tracker dips several degrees suggesting he may have been immersed. Quite often he spends some time near Lake Guembeul (for example on 13 November, image above) and he may have more success there. Or in the flooded wetland area near his roost, although it will be starting to dry out now.
When UV is travelling between his roost area and other places he is often under 100m ASL, but sometimes he has a good look around from a rather higher elevation. On 6 November he flew at over 200m ASL during his travel to and from roost. His highest point in a fix was 661m on his return trip. A good reason for one of Paul’s elevation graphics!
Yesterday’s weather satellite image showed the silt outflow has lessened considerably. It’ll be interesting to monitor what effect that has on UV.