Whomever wrote the line:
According to a history teacher, one student’s reply to what started WWI: some guy named Archie Duke shot a duck because he was hungry…..
Likely stole it from Monty Phyon:
"I heard that it started when a bloke called Archie Duke shot an ostrich 'cause he was hungry"

The assination of Archduke Ferdinand of Austria-Hungary triggered WW1

A likely breakdown for the orginial is a simple mind like a child to confuse
Archie Duke for Archduke
shot a - refers to fact that the Archduke was shot
ostrich for the former of Austria-Hungary, the country the Archduke was heir to the throne of
hungry for the later of Austria-Hungary

In this rendition a duck is swapped for ostrich and could be tied to the fact that Ferdinand was the name of the duck in movie Babe, a popular childrens movie

In a simplistic mind they knew they needed Archduke, that something was shot, Austria-Hungary was involvedthus:
one student’s reply to what started WWI: some guy named Archie Duke shot a duck because he was hungry…..