30 races across the Sahara

Our satellite-tagged Osprey, 30(05) continues to make staggering progress on her autumn migration. The latest data shows that at 9pm last night she was roosting in the remote desert of Western Sahara just eight days after leaving Rutland.

The previous data from the 30’s satellite transmitter had shown that on the night of 4th September she had roosted north-east of Rabat in northern Morocco. Next morning she resumed her migration at first light, passing Rabat at 8am local time (7am GMT) and then maintaining a perfect south-westerly course for the next seven hours at altitudes of between 250 metres and 1000 metres. By 3pm she had already flown 320km and at that point she made a distinct turn to the south. Two hours later the vast Atlas Mountains would have been prominent on the horizon and, like her autumn migration in 2013, she turned to the south-west in order to skirt across the western foothills of the mountains; thereby avoiding the high peaks further east.

30 skirted around the western end of the Atlas Mountains

30 skirted around the western end of the Atlas Mountains

An Osprey's eye view of the Atlas. This Google Earth image shows why 30 flew around the mountains, rather than over them

An Osprey’s eye view of the Atlas. This Google Earth image shows why 30 flew around the mountains, rather than over them

She may have missed the high mountains, but nevertheless at 7pm 30 was migrating at an altitude of more than 3000 metres and an hour later – with darkness falling – she was still going: heading due south at 33kph at an altitude of 1820 metres. Finally, at around 8:30pm she settled to roost for the night in a cultivated area just south of the mountains having flown a total of 536 kilometres during the day; her longest day’s flight thus far.

30 flew 536km on 5th September

30 flew 536km on 5th September

Next morning 30 resumed her migration later than the previous day; by 10am she was only 18km south-west of her overnight roost suggesting that she may have found somewhere to fish before resuming her migration. At midday she was just 11km from the coast, but at that point she turned to a more southerly heading, passing to the east of Tiznit and then past Guelmin. As she headed south the terrain would have become increasingly arid with spectacular rock formations and ridges. By 5pm she was passing just a few kilometres to the east of the area where another of our satellite-tagged birds, 09(98) sadly came to grief in 2012. The film below, made by Moroccan wildlife film-maker Lahoucine Faouzi, gives you an idea of just how inhospitable this area is.

At 6pm 30 passed over a spectacular ridge that you can see in Lahoucine’s film. Satellite-tracking studies have shown that many Osprey use this ridge to aid their navigation, and sure enough, 30 made a distinct turn to the south-west as she passed over this ridge; exactly as she had done on her autumn migration last year.

As in 2013 (red line), 30 made a distinct turn to the south-west when she flew over a spectacular ridge in the Sahara

As in 2013 (red line), 30 made a distinct turn to the south-west when she flew over a spectacular ridge in the Sahara

30 continued migrating for another two hours, before settling to roost in an area of sparse vegetation at 8pm having flown 352 kilometres during the course of the day. It is fascinating to see how her route almost exactly mirrored that of her flight on 4th September 2013. Both her morning and evening roosts were within 15km of her previous journey.

30's flight on 6th September was almost exactly the same as her journey on 4th September in 2013

30’s flight on 6th September was almost exactly the same as her journey on 4th September in 2013

Yesterday morning 30 was migrating again at first light. Conditions must have been good for migration because during the course of the day she maintained an almost-perfect south-westerly heading at altitudes ranging from 360 metres to 1210 metres. In just over 10 hours of migrating 30 flew 561 kilomtres; an average speed of more than 50kph. She eventually settled to roost on the desert floor just after 5pm in an extremely remote part of Western Sahara.

30's roost site last night could hardly have been more remote

30’s roost site last night could hardly have been more remote

30 flew 561km across the Sahara on 7th September

30 flew 561km across the Sahara on 7th September

This all means that just eight days after leaving Rutland Water 30 has flown a remarkable 3665km. If she maintains similar speeds, she could arrive at her wintering site on the Senegal coast as early as Wednesday…watch this space! Last year she did the migration in 11 days; and she’s certainly on course to at least match that again this year.

Don’t forget that you can also view 30?s migration on your own version of Google Earth. To find out how, click here.