In the light of what I now know about evolution, swallow migration doesn't surprise me as much as it did. Afterall, there are great migrating species in the seas, and overland as well as in the skies.
Whatever the method it has most certainly evolved over millions of years.
When we explained to you about the evolution of the flight of birds, then we knew how birds fly; we understood the mechanics; the laws of aerodynamics are known; we could look at intermediate forms which had feathers but no wings, or which could glide but which can't fly; we could show you lots of animals which glide from tree to tree.
Compare that with spectacular cases of instinct like the migration of the Monarch Butterfly. So far as I know, we don't understand what is happening: what the proteins are, what the genes are, how the Monarch Butterfly differs genetically from relatives that don't migrate, and
why the Monarch Butterfly makes this crazy migration.
So I can't say "evolution can explain this" --- because I don't know what
this is. I guess that evolution will be the explanation for the migration of the Monarch Butterfly like it turns out to be the explanation for stuff that we understand in depth and detail; but my only argument for this is that evolution
is the explanation for stuff that we understand in depth and detail. It's worked fine so far, why should it break down over something we don't know much about?
And let's face it, humans have evolved skills which now enable them to circumnavigate the world and have now taken to navigating outer space! And not so long ago you might have been deemed mad to suggest such a thing.
This is a false analogy. We did not "evolve" ways of finding magnetic north, the latitude, the longitude, and so forth. We
discovered them, and passed them down, not in our genes, but through cultural transmission.
Evolution is not that easy. There is a vague poetic analogy with human cultural development, but it's nothing that we can learn from or reason with --- indeed, on the thread where you asked how evolution works, you discovered that this analogy is horribly misleading.
An evolutionary explanation has to be in terms of mutation and selection: the fact that human material culture progresses is not a substitute for such an explanation.
Edited by Dr Adequate, : No reason given.