Two years ago, I attended a lecture (and demonstration) at Melbourne University which was the inspiration for two upcoming novels: “Immersion” and “Ersatz”. Although this article suggests that the active agent is a protein rather than grains of iron, it comes to the same conclusion.
https://www.pbs.org/wgbh/nova/article/birds-quantum-entanglement/
[Gerald St Clare, 22 August, 2020]