What is one common repellent used against vertebrate pests?

Capsaicin is a common repellent used against vertebrate pests primarily due to its active compound, which is found in chili peppers. It acts by producing a burning sensation in mammals, including rodents, thereby deterring them from areas where it has been applied. This property makes capsaicin particularly effective for protecting gardens and crops from being nibbled on by various vertebrate pests, such as squirrels and deer.

The use of capsaicin is favorable because it is a natural substance, and its effectiveness can last for some time when properly applied. Many garden products containing capsaicin are marketed as environmentally friendly solutions to pest problems, aligning with growing consumer preferences for natural pest control methods.

Other substances mentioned, like mint oil and citronella, have their uses, particularly in repelling insects rather than vertebrates, making capsaicin more specifically suited for this context. Water does not serve a repelling purpose for pests at all, which further emphasizes capsaicin's unique effectiveness.