mesmerism

Here, in fact, lies the whole secret of magnetism, and all delusions of a similar kind:

Mesmerism is a bit of medical quackery developed in the 18th-century by Dr. Franz Anton Mesmer.

Mesmer plagiarized Hell's magnetic therapy and posited that it works because there is a very subtle magnetic fluid flowing through everything but which sometimes gets disturbed and needs to be restored to its proper flow. Hell, Mesmer theorized, was unblocking the flow of this magnetic fluid with his magnets. Mesmer eventually discovered that he got the same results without the magnets. Rather than attribute this to the placebo effect, he posited that "animal magnetism" accounted for his ability to correct the flow of the universal magnetic fluid. (Today, the term "animal magnetism" means mesmerism or hypnotic power, but I have heard it misused more than once by females to mean a sexy male and by members of both sexes to mean someone to whom animals are attracted.)

this is in reference to the birds in migration article and magnets as the possible answer.