The short answer to whether Nyjer seed is the same as thistle seed is no, the two are entirely different products from unrelated plants. Nyjer is a marketable oilseed crop imported for wild bird feeding, while true thistle seed comes from invasive, prickly weeds in the genus Cirsium. The widespread confusion is understandable, as the term “thistle seed” is frequently used in marketing and conversation as a common, albeit botanically incorrect, nickname for Nyjer. This tiny, black seed is a high-fat food source that is immensely popular with certain small bird species.
Botanical Identity and Origin
Nyjer seed is derived from the annual herb Guizotia abyssinica, a plant native to the highlands of Ethiopia, though it is now primarily cultivated in parts of Africa and India for commercial export. This crop is a member of the sunflower family, Asteraceae, and is valued for its tiny black seeds that contain roughly 40% oil. True thistle belongs to various species within the same plant family but is considered a noxious weed with sharp, spiny leaves. The seeds harvested from these wild plants are not the same product sold as Nyjer birdseed.
To prevent the introduction of foreign weeds, governments in the US and Canada mandate a strict sterilization process for imported Nyjer seed. The seed must be heat-treated at high temperatures, often around 248°F (120°C) for 15 minutes, before it can be sold. This process devitalizes any potential weed seeds, including the parasitic dodder, ensuring they cannot germinate if they fall beneath a bird feeder. The spelling “Nyjer” was adopted to clarify its identity and avoid confusion with the invasive weed.
The Source of the Naming Confusion
The persistent misnomer of “thistle seed” is rooted in the history of bird feeding and commercial marketing. When the seed gained popularity in North America, it was informally called thistle seed, likely because finches—the main consumers—are known to feed on the seeds of wild thistle plants. This casual association established the common name in the minds of consumers.
The Wild Bird Feeding Institute (WBFI) officially trademarked the phonetic spelling “Nyjer” in the late 1990s to combat this confusion and distance the product from the invasive weed. Despite this effort, many retailers and consumers still use the term “thistle feeder” or “thistle seed” interchangeably with Nyjer. The specialized feeders required for the small seed are sometimes labeled with the older name, reinforcing the inaccurate link.
Feeding Specifics for Nyjer Seed
Nyjer seed is a favorite food source for small, seed-eating birds, particularly those in the finch family, due to its small size and high-fat content. The American Goldfinch, Pine Siskin, and Common Redpoll are among the most frequent visitors to Nyjer feeders. House Finches and Purple Finches also readily consume the seed, which provides necessary energy during winter months and breeding season.
Because the seed is tiny and expensive due to importation and processing, it requires specialized feeders to prevent waste. The most effective options are tube feeders with very small feeding ports or mesh sock feeders, which allow birds to cling while extracting the seed. Nyjer seed can lose its freshness and high oil content quickly, so it should be purchased in small quantities and stored in a cool, dry place.