  We observe that the analogue of the Gelfand-Zeitlin action on gl(n,C), which
exists on any symplectic manifold M with an Hamiltonian action of GL(n,C), has
a natural interpretation as a residual action, after we identify M with a
symplectic quotient of the product of M with T*GL(n-1,C)x...xT*GL(1,C). We also
show that the Gelfand-Zeitlin actions on T*GL(n,C) and on the regular part of
gl(n,C) can be identified with natural Hamiltonian actions on spaces of
rational maps into full flag manifolds, while the Gelfand-Zeitlin action on the
whole gl(n,C) corresponds to a natural action on a space of rational maps into
the manifold of half-full flags in C^{2n}.
