Today was a real spring like day – really warm in the sun when we were in the forest rebuilding osprey nest B14 in Nairnshire. This nest has been in use for 20 years and has always reared two or three young each summer – three in 2014. My recent check showed that a storm had broken one of the supporting branches and most of the nest had fallen to the ground, and it would be impossible for the ospreys to make a secure nest this spring. So this morning we went there to rebuild it, Ian climbed the 80 ft Douglas fir and made a secure base for a new nest and we sent up bags of moss and leaf mould to make a solid nest. Now they will find a good nest and as a bonus a nice new perch beside the new nest. In the evening I checked the satellite data for the tagged ospreys and found that this morning Blue XD, a Strathspey male, was roosting near a big reservoir in southern Mauritania and was ready to set off over the Sahara Desert. He had left his Casamanache wintering site at 1040am on 18th March and yesterday flew across northern Senegal into Mauritania. His tracks in the afternoon crossing the Senegal/Mauritania border were superb. With the new GSM transmitters we get information every minute in full sunshine and the photo below is a shot of his track from GoogleEarth, looking along the earth so one can see his altitudinal track as well. It shows really well the thermal climb and glide migration of an osprey over the land. In this picture his lowest point after crossing the border (yellow line) was 224 metres asl (the land there is about 70 metres above sea level) while his highest point of his climb was 2172 metres (7125 feet) before the long glide north. It’s absolutely fascinating that we can now see how they make the migration over the Sahara. Hopefully he will make a good flight north and in April will probably come across the old male from B14, because they both fish one particular loch.
20th March afternoon migration track over Senegal/Mauritania
