  We investigate the Poisson geometry of the Marsden-Weinstein reductions of
the moment map associated to the cotangent bundle of the space of
representations of a quiver. We show that the stratification by representation
type equals the stratification by symplectic leaves. The deformed symplectic
quotient singularities - spectra of centres of symplectic reflection algebras
associated to a wreath product - are shown to be isomorphic to reductions of a
certain quiver. This establishes a method to calculate when these deformations
are smooth. Furthermore, the isomorphism identifies symplectic leaves and so
one can give a description of their symplectic leaves in terms of roots of the
quiver.
