I knew a simple soldier boy
Who grinned at life in empty joy,
Slept soundly through the lonesome dark,
And whistled early with the lark.
In winter trenches, cowed and glum,
With crumps and lice and lack of rum,
He put a bullet through his brain.
A lark is a bird known for it’s singing. Having the boy whistle in the early morning with this bird showed that he was happy and carefree.
Suicide in the Trenches