The story
The noun is derived from scare (“to frighten, startle, terrify”) + crow (“bird of the genus Corvus”). The word displaced other terms such as bogle (now dialectal, dated), sewel or shewel, and shoy-hoy (perhaps imitative of the cry of crows). The verb is derived from the noun.
First known use, by meaning
- from 1530s An effigy, typically made of straw and dressed in old clothes, fixed to a pole in a field to deter birds from eating crops or seeds planted there.
Etymology from Wiktionary, CC BY-SA 4.0.