Niger Seed is Guizotia abyssinica. This is an annual herb, which is noteworthy due to its “oil-producing” seeds. Apparently, it has been researched in the United States as a potential oil crop, but found to be of less promise than other oil seed crops already under cultivation. It is considered of little threat of becoming a noxious weed, should it escape into wildland areas. Nevertheless, it is an exotic plant not native to California and should not be encouraged to grow and produce seeds.
Agencies within California intercept a number of exotic insects, diseases, nematodes, and plants each year at our airports, seaports, border stations, etc. These interceptions are of plants and animals that we do not want in California and that may pose a threat to our native fauna and flora. When we travel, we are often annoyed by the people who stop us at the border and inspect our luggage and ask us questions about what we are bringing back from wherever we have been. We should remember that they are trying to prevent the introduction of pest plants and animals into California. This activity over time is very useful in keeping exotic pest species in California to a minimum.
In the case of Niger seed in bird feed, if the package was labeled “heat-treated.” The heat treatment may be improperly done, so a percentage of the seed is still viable. You should complain to whomever sold you the seed. They should be aware that their product is not meeting package label specifications. In the meantime, if you wish to continue using this seed for bird food, place the contents of the package into a baking dish and heat it in the oven for two hours at 200º F. This treatment should insure that all the seed has been killed.