  Given a rational map $f:\widehat{\mathbb C}\to\widehat{\mathbb C}$ on the
Riemann sphere, we define $\mathrm{Deck}(f)$ to be the group of M\"obius
transformations $\mu$ satisfying $f \circ \mu = f$. In this note, we consider
the groups $\mathrm{Deck}(f^k)$, where $f$ is a \emph{bicritical} rational map
(that is, a rational map with exactly two critical points) and $f^k$ denotes
the $k$th iterate of $f$. In particular, we give a complete description of
which groups (up to isomorphism) arise as the groups $\mathrm{Deck}(f^k)$ for
bicritical rational maps $f$.
