Nimrod continued his flight down through the Sahara Desert and into northern Mauritania, and yesterday morning appeared to be heading directly towards the Atlantic coast, where he could catch his first fish since leaving the French coast. But he surprised me again by changing course to the south and keeping well inland from the coast, passing 20 kilometres east of the locality where Morven is living on the Mauritanian coast, and by late afternoon was to the west of the capital Nouakchott and appeared to be heading for Senegal. I find it really fascinating trying to understand the changes he makes along his migration route. I also find it nice to think that even with our fantastic technology and knowledge, which allows us to track his movements and correlate them with geography, weather, ecology and the seasons, we will never know what he (or any other migrating bird) is actually thinking. It was probably his fit condition and a change in weather that stimulated his departure from Ile d’Oleron – but had he already decided to fly non-stop to Morocco before he set off? Did he decide to fly through the night, because the moon was bright, or because he just wanted to get quickly to Africa? And then why did he turn south, 30 kilometres or so from the Mauritanian coast, where he could fish, and instead head on south over the deserts and delay eating for another day or more?