In 1932 the Australian army went to war against some 20,000 emus, armed with machine guns. The army lost.
Seriously.
Campion district, Western Australia, November and December 1932. After breeding season the emus had moved onto the wheat fields and were eating the crop. Many of the farmers were First World War veterans settled there after the war, so they asked for what they knew: machine guns. Defence Minister George Pearce said yes, partly because the birds would make good shooting practice.
Major G. P. W. Meredith went in with two Lewis guns and 10,000 rounds. The emus split into small groups, ran fast and kept going after being hit. On the second attempt he fired 9,860 rounds and claimed 986 confirmed kills, a bullet and a bit per bird at best. His own verdict:
Major G. P. W. Meredith, 1932
They can face machine guns with the invulnerability of tanks.
What did work, in the end, was boring: bounties per bird. In 1934 farmers claimed 57,034 of them in six months.
Emus 1, army 0.