  Evidence from pulsar wind nebula symmetry axes and radio polarization
observations suggests that pulsar motions correlate with the spin directions.
We assemble this evidence for young isolated pulsars and show how it can be
used to quantitatively constrain birth kick scenarios. We illustrate by
computing several plausible, but idealized, models where the momentum thrust is
proportional to the neutrino cooling luminosity of the proto-neutron star. Our
kick simulations include the effects of pulsar acceleration and spin-up and our
maximum likelihood comparison with the data constrains the model parameters.
The fit to the pulsar spin and velocity measurements suggests that: i) the
anisotropic momentum required amounts to ~10% of the neutrino flux, ii) while a
pre-kick spin of the star is required, the preferred magnitude is small
10-20rad/s, so that for the best-fit models iii) the bulk of the spin is
kick-induced with $\bar \Omega$ ~120rad/s and iv) the models suggest that the
anisotropy emerges on a timescale $\tau$ ~1-3s.
