The targeted animals are culled because they are considered economically harmful pests to agricultural crops, livestocks or properties; pathogen-carrying hosts/vectors that transmit cross-species/zoonotic diseases; or for population control as a mean of protecting other vulnerable species and ecosystems.
Varmint hunters may hunt to exterminate a nuisance animal from their own property, to collect a bounty offered by another landowner or the government, or simply as a hobby.
[3] Air rifles are commonly used in built-up environments, where the targets might not be particularly far away but are high up on trees/structures or in obscure corners, and the risk of overpenetration, ricochets and stray shots need to be minimized.
Airguns are more powerful and accurate than blowguns, but much quieter and with less terminal damage than firearms, and thus more suitable in urban and suburban environments where noise complaint and ballistic safety can be an issue.
Varmint hunting is also potentially selecting for behavioral changes that are desired, animals avoiding human populated areas, crops, and livestock.