  We prove the positivity of Lyapunov exponents for the normal form of a Hopf
bifurcation, perturbed by additive white noise, under sufficiently strong shear
strength. This completes a series of related results for simplified situations
which we can exploit by studying suitable limits of the shear and noise
parameters. The crucial technical ingredient for making this approach rigorous
is a result on the continuity of Lyapunov exponents via Furstenberg Khasminskii
formulas.
