Amy Harmon, writing for the New York Times:
Interestingly, the predator activity in Dr. Hofmeester’s plots did not decrease the density of the mouse population itself, as some ecologists had theorized it might. Instead, the lower rates of infected ticks, Dr. Hofmeester suggested in the paper, published in Proceedings of the Royal Society B, may be the result of small mammals curtailing their own movement when predators are around.
The ecologists must have theorized multiple possible mechanisms of action.
I wonder what else was on their list.