In reality, it wasn’t an actual war, just a coordinated effort by the Australian military to rid itself of a large population of emus that had become a nuisance for destroying crops.
Taking place in 1932, while Australia was still feeling the effects of the Great Depression, the migration of around 20,000 emus exacerbated matters when farmers lost significant portions of their crops to these birds.
In October, the Australian military sprang into action, fielding a small number of soldiers along with volunteers from settlers looking to curb emu populations. The soldiers were armed with Lewis guns—an early British machine gun, and set out to round the birds into one place to maximize the number killed.
As it turns out, if you’re a flightless bird, you have to compensate for your lack of flying ability somehow. Emus are fast.
The first ambush of the war ended poorly, with the herded emus scattering and evading, with only a dozen killed. The second, despite 1000 emus being clustered in one place, was similarly disastrous, as one of the guns jammed after a brief period of sustained fire, with a similar kill count.
Efforts to innovate in the face (beak?) of such ingenuity also ended in failure; trucks could not match emus in speed, and offroad driving proved too rough for gunners to fire while in pursuit.
“The machine-gunners’ dreams of point blank fire into serried masses of Emus were soon dissipated. The Emu command had evidently ordered guerrilla tactics, and its unwieldy army soon split up into innumerable small units that made use of the military equipment uneconomic. A crestfallen field force therefore withdrew from the combat area after about a month.”
Emus remain in Australia to this day, where farmers have opted for fences in place of machine guns to keep them away from crops.