Scarecrows

A scarecrow or hay-man is a decoy or mannequin in the shape of a human. It is usually dressed in old clothes and placed in open fields to discourage birds such as crows or sparrows from disturbing and feeding on recently cast seed and growing crops.

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.

Crows can be a substantial problem for gardens in the springtime: they can work down a row pulling up recently sprouted corn to eat the remaining seed/seedlings. In the southern Appalachians another common method of scaring off crows was use of a dead crow hung upside down from a pole.

Modern scarecrows, though still essentially decoys, seldom take a human shape. On California farmland, highly reflective aluminized PET film ribbons are tied to the plants to create shimmers from the sun. Another approach is automatic noise guns powered by propane gas. One winery in New York uses inflatable tube men or airdancers to scare away birds.

In the United Kingdom, where the use of scarecrows as a protector of crops dates from time immemorial, and where dialects were rife, there are a wide range of alternative names such as:

Bodach-rocais (lit. "old man of the rooks")

The impact of the scarecrow extends beyond its immediate utilitarian function.

In Kojiki, the oldest surviving book in Japan (compiled in the year 712), a scarecrow known as Kuebiko appears as a deity who cannot walk, yet knows everything about the world.

...
Wikipedia