why calcium is more reactive than strontium or barium?

Question

Strontium(Sr) and barium (Ba) both are group ii metal and lie below Calcium. As for metal we know that reactivity increases as we go down in the same group but calcium is placed higher in the reactivity series as in http://en.wikipedia.org/wiki/Reactivity_series
WHY

Answer 1

I looked up to the standard reduction potentials, and reducing power increases, as you would expect, on going down the series, although there is not much in it.

So I suspect Wikipedia just got it wrong.

A star for spotting it.