Start of spring walk (5)
I believe the answer is:
march
I believe this is a double definition.
'start of spring' is the first definition.
(first month of spring)
'walk' is the second definition.
(march is a kind of walk)
(Other definitions for march that I've seen before include "The month for military movement" , "Colonel Bogey, for example" , "Journey undertaken by army etc" , "Stride; month" , "Month - advance in step" .)