Rhythm of Morning

Sometimes there is a song in the morning 
Of blackbird or wren,
A flit through the hedge,
Often unseen
Though shrill the call;
Or thrush
In rhythm breaking a shell,
Driving a rivet into a stone.
Lamenting all today,
The world spins darker
The tune is changed;
The song replaced by constant roar
Of pounding wind,
Forceful and strong,
Whistling through any 
Gap unseen,
A broken tune 
Of slate against stone 
Driving the rain to a different rhythm
To the one in my heart.