I’m taking a required course for one of my majors, and I ended up reading about quantum biology while looking into how animals sense their environments. My physics background is pretty limited, but I’m particularly interested in the proposed role of cryptochrome in birds’ magnetic navigation.

My question is: if disrupting cryptochrome changes a bird’s ability to orient itself, how do researchers establish that this is specifically because they disrupted a radical-pair magnetic compass? How would they rule out effects on vision or other processes that could also affect the bird’s behaviour?

Are there experiments that isolate the proposed magnetic-sensing function while leaving those other functions intact? I’d appreciate an explanation of what a convincing control would look like, or a paper that tackles this.