The potential for bird seed to spread invasive weeds like Palmer amaranth and waterhemp, which are highly competitive and often herbicide-resistant, is a concern for agricultural producers. A recent incident in Spokane, Washington, where a Palmer amaranth plant was found in a Safeway parking lot and linked to bird seed, highlighted this risk. These aggressive pigweeds can produce over 100,000 seeds per plant. While waterhemp has been found in Canadian provinces like Manitoba, Ontario, and Quebec, Palmer amaranth has not yet been detected in Canada.
Despite the prevalence of this issue in the United States, Canadian manufacturers believe the likelihood of bird seed spreading these weeds in Canada is low. Most Canadian bird seed is sourced domestically. For imported ingredients, the Canadian Food Inspection Agency (CFIA) mandates that bird seed must be free from regulated weed seeds, pests, soil, and plant debris. Specific requirements vary based on origin, destination, commodity, and end-use, with some seeds like nyjer undergoing irradiation.
Companies like the Wild Bird Trading Company and Armstrong Milling Co. implement rigorous cleaning and screening processes. Wild Bird Trading Company uses a broker to source seed from Western Canada, which is then double-cleaned to remove immature seeds and shells. Armstrong Milling Co., a Safe Quality Food certified mill, has its suppliers sign compliance agreements and subjects all ingredients to a triple-screening process.
Control of weed seeds is also a shared responsibility with farmers, who must manage weeds on their land and ensure equipment is clean. While these pigweeds may emerge later than other weeds, they can outcompete crops and spread rapidly if not managed before harvest. Spot management, hand weeding, and immediate contact with a weed inspector are recommended if invasive species are suspected, as their spread to agricultural land could impact yields, increase food costs, and contribute to herbicide resistance, while spread in residential and wild areas could displace native plants and reduce biodiversity.