Green’s Dictionary of Slang

(US) a nickname for an inhabitant of Oregon.

1862

Oregon Statesman in G. Barth All Quiet on the Yamhill (1959) 23 June 58: The nicknames for Oregonians, in most common use, is ‘Webfoot,’ but some insist that ‘Lop-ear,’ others that ‘Flop-ear’ is the proper designation.