A very familiar winter home

When 30’s last batch of data arrived, we were speculating how far south she would continue to fly. Would she winter in Northern Senegal or would she head further south towards The Gambia or Guinea? Well, it now looks as though we’ve got an answer. At 3pm on Monday afternoon 30 stopped on the Senegal coast midway between Dakar and St Louis in Northern Senegal. More than 48 hours later, at 9pm on Wednesday evening, she was still there; suggesting she has arrived at her winter home.  If her location on the Senegal coast sounds familiar, that’s because, remarkably, it is just 2km south of where our previous satellite-tagged Osprey, 09(98) used to winter!

The previous data had shown on Sunday night, 30 roosted just north of the Senegal River. By 8am next morning she had moved 2km south from her overnight spot and was perched beside the river, almost certainly eating breakfast. She was probably disturbed by local fisherman soon afterwards, because an hour later she was perched 8km to the south-east. Then, at 10am she had moved again: a further 1km to the south-east.

She must have resumed her migration sometime after 10:30am because, at 11am, the next GPS position showed that she was 9km to the South-east, flying south at 21kph at an altitude of 500 metres. She continued on this course for another hour, before changing to a more south-westerly heading at midday. She must have know she was now close to her winter home, and three hours later she arrived on the coast after a day’s flight of just under 100km.

The final leg of 30's migration on 9th September

The final leg of 30’s migration on 9th September

Having arrived on the coast, 30 has made only short local flights of up to 5km. This behaviour is typical of an adult Osprey on the wintering grounds. They spend most of their day perched in a favoured location and then make short flights to fish once or twice a day. In 30’s case her favourite perches seem to be located in an area of scattered trees, less than 100 metres from the beach. From here it is just a short flight out to sea, where a wealth of fish will make hunting very easy for an adult Osprey.

If 30 does remain in this area for the winter, her favourite perches are just 2km south of the ones favoured by 09 during the winter of 2011/12. This means that she and 09 would have been neighbours for seven winters. When you consider that 09 wintered almost 1500km away from the one other Rutland Osprey that we have tracked using a GPS transmitter, this is a truly remarkable co-incidence. As the map below shows, 30’s daily flights (red dots and yellow lines) are already over-lapping with the flights (in orange) of 09 during the winter of 2011/12. If only he was still alive!

The movements of 30 at her wintering site (yellow line) compared to those of 09 in 2011/12 (orange line)

The movements of 30 at her wintering site (yellow line) compared to those of 09 in 2011/12 (orange line)

Assuming that she has arrived at her winter home, 30’s migration is the fastest we have recorded. She flew over 4600km in just 12 days, four days quicker than 09’s 16-day migration in autumn 2011. When you compare their migration routes, 30’s flight was more direct through Europe, but once they arrived in Africa, they were remarkably similar, particularly through Morocco. The data demonstrates what incredible navigators adult Ospreys really are.

30's migration (yellow line) compared to 09's autumn migration in 2011 (orange line)

30’s migration (yellow line) compared to 09’s autumn migration in 2011 (orange line)

The next batch of data should arrive from 30’s transmitter over the weekend, so check back for an update on Monday. In the meantime, don’t forget you can upload all her migration data onto your own copy of Google Earth. Click here to find out how. Or check out our interactive Google maps page.