Mass equidistribution for Saito-Kurokawa lifts

Let $F$ be a holomorphic cuspidal Hecke eigenform for ${\mathrm{S}\mathrm{p}}_4(\mathbb{Z})$ of weight $k$ that is a Saito–Kurokawa lift. Assuming the Generalized Riemann Hypothesis (GRH), we prove that the mass of $F$ equidistributes on the Siegel modular variety as $k⟶\mathrm{\infty }$. As a corollary, we show under GRH that the zero divisors of Saito–Kurokawa lifts equidistribute as their weights tend to infinity.