Abstract The response of superfluid spherical nuclei to an external quadrupole field is considered. The mixed (r,λ) representation technique is developed, being the generalization of the coordinate (r) representation for magic nuclei. The transition densities ptr(r) are shown to possess sharp surface bumps of hydrodynamical nature and pronounced volume quantum components. The shapes of transition densities of 2+2 states in some typical nonmagic nuclei are predicted.