scarecrow

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.

(by extension, derogatory) A person regarded as resembling a scarecrow (sense 1) in some way; especially, a tall, thin, awkward person; or a person wearing ragged and tattered clothes.

(dated) Synonym of crow scarer (“a farmhand employed to scare birds from the fields”)

Anything that appears terrifying but presents no danger; a paper tiger.

(military, World War II, historical) Military equipment or tactics used to scare and deter rather than cause actual damage.

The black tern (Chlidonias niger).

The hooded crow (Corvus cornix).