Groups of New Orleanians have organised themselves into volunteer militias tackling everything from home repairs to grass-cutting in the parks.

ECONOMIST: New Orleans is recovering its energy, but not its people

Grass-cutting ants occur in the Chaco region of north Argentina and Paraguay and belong to a subgroup of leaf-cutting ants that specialise in harvesting grass leaves.

BBC: Earth News - Ant's head balancing act revealed by video

The latter song was written three years before Cook's "Idol" run, when he was cutting his teeth as a grass-roots rocker.

CNN: 'Idol' champ eyes long-term success