Which of the following is NOT a source of weed infestations?

• A. Humans
• B. Wind
• C. Birds
• D. Farm equipment

Answer: (C)

Spreading weed infestations happens through several channels that move seeds from one place to another. People carry seeds on clothing, shoes, and gear, and contaminated soil can hitch a ride on vehicles, tools, and farm equipment. Wind can lift lightweight seeds and blow them across fields and along rights-of-way. Animals contribute as well, with birds able to pick up seeds on their feathers or feet or swallow seeds and later excrete them in new locations. Because birds can transport seeds, they are indeed a source of weed spread. So the idea that birds are not a source isn’t accurate. If a test question asks for what is NOT a source, this item would be flawed since all these vectors can contribute to weed infestations; in practice, addressing all pathways—cleaning equipment and clothing, inspecting vehicles, and managing weed seed production—helps reduce spread through any of these routes.