Science can be exact and it can be probable or highly probable. The early naturalist Gilbert White believed Swallows spent the winter in a torpid state in ponds, if I remember correctly. The fact, the certainty, of the science now is they migrate to Africa, south of the Sahara. We now know British Cuckoo's migrate by two routes to Africa, one via Italy and one via Spain. We have put trackers on them, that's science and it's exact in those particular details. How the juveniles find their way is more than science, it's a great wonder. Let's not seek to denigrate science as some fundamentalist groups do by silly arguments. When the sea rises due to ice melting, in a few hundred years time, if we do not stop the rise in co2, much of the low lying areas around the world will flood, including London. There will not be many climate sceptics then with potty ideas or paid naysayers by fuel companies. D.