A 19th Century Take on Scarecrows
The 1881 Household Cyclopedia of General Information gives the following advice: Machinery of various kinds, such as wind-mills in miniature, horse rattles, etc., to be put in motion by the wind, are often employed to frighten crows; but with all of these they soon become familiar, when they cease to be of any use whatever.
The most effectual method of banishing them from a field, as far as experience goes, is to combine with one or other of the scarecrows in vogue the frequent use of the musket. Nothing strikes such terror into these sagacious animals as the sight of a fowling-piece and the explosion of gun powder, which they have known so often to be fatal to their race.
Such is their dread of a fowling-piece, that if one is placed upon a dyke or other eminence, it will for a long time prevent them from alighting on the adjacent grounds. Many persons now, however, believe that crows like most other birds, do more good by destroying insects and worms, etc., than harm by eating grain.
— Henry Hartshorne