  This note attempts to interpret some of the recent findings about a downtrend
in the mean azimuthal velocity of low [alpha/Fe] thin disc stars with
increasing metallicity. The presence of such a trend was predicted in the model
of Schoenrich & Binney (2009), albeit with a slightly steeper slope. We show
that in a simple picture a Galactic disc without mixing in angular momenta
would display an exceedingly steep trend, while in the case of complete mixing
of all stars the trend has to vanish. The difference between model and
observational data can hence be interpreted as the consequence of the radial
abundance gradient in the model being too high resulting in an underestimate of
the migration strength. We shortly discuss the value of eccentricity
distributions in constraining structure and history of the Galactic disc.
