1 Erratum to: Nonlinear Dyn DOI 10.1007/s11071-014-1686-5

The following information was omitted in the original publication: The proof at the beginning of Section 3 applies only to regular Hopf bifurcations involving a pair of bifurcating (pure imaginary) eigenvalues. Note however that, although simple Hopf bifurcations are impossible, the well-known Hamiltonian–Hopf bifurcation involving four bifurcating eigenvalues is of course ubiquitous in Hamiltonian systems. Note that this Hamiltonian–Hopf bifurcation cannot occur in our three-dimensional system though.