What do you really know about Nyjer (formerly known as thistle) seed? None of the foods we feed our birds has caused more confusion than these tiny seeds.
Nyjer seed is grown in Ethiopia, India and Asia. Perhaps it was originally called thistle when it was imported for bird seed, because the seed does resemble the seeds of the thistle plant which goldfinches depend on for food. Finches also use the thistledown to line their nests. Eventually the name was changed to niger seed to differentiate it from the spiny and invasive thistle plants of this country—because it’s definitely not the same thing! In 1998, the Wild Bird Feeding Industry changed the name again to Nyjer and trademarked the name, in part to ensure the correct pronunciation. Nyjer is simply irresistible to goldfinches and other finches because of its high oil content.Nyjer flower is small and yellow. Its seeds are high-oil seeds that are pressed to make cooking oil in its native countries, but 60% of the world’s production is imported into the U.S. as bird seed. And that’s where E. George Strasser enters the picture!
The problem with imported Nyjer seed is that it’s often accompanied by seeds of the dodder family. Dodder is a parasitic type of plant that grows no leaves of its own. The seeds can stay dormant in the ground for up to 20 years. When something grows near it, the seeds sprout roots which then begin to infiltrate the host plant. It then produces seed, kills the host plant and dies—and the whole cycle begins again. Obviously, this is not a plant we want in this country! In 1982, huge shipments of Nyjer seed at port in California were found to be infested with dodder seeds. Something had to be done to clean the Nyjer or it wouldn’t be allowed into the U.S.
George then worked for the USDA and was given the task of inventing a way to eliminate the dodder seeds in the Nyjer shipments. In the process, he had to make sure the oil content of the Nyjer wasn’t destroyed so the seed would still be viable as birdseed.
After several failed attempts, George finally devised a method where the contaminated Nyjer seed was run through ovens on huge conveyor belts. The seeds were heated to the boiling point which was 212 degrees F. for dodder seed. Dodder is mostly water, so it reached the boiling point faster than Nyjer seed and in the process was killed, while the Nyjer wasn’t. But although the oil in the Nyjer seed remained, the seeds were rendered sterile in the process. There’s no guarantee that Nyjer won’t sprout in your garden or lawn, but it’s highly unlikely. George actually solved two problems. Not only were the shipments saved and our finches supplied with nutritious, high-oil seeds, but Nyjer is lawn and garden friendly as well! Although the method may have changed slightly over the years, all Nyjer seed coming into this country continues to be heat treated as required by the USDA.
George’s method for saving our finch seed was published in Seed Science & Technology in 1988, 16, 501-505. The article was entitled “Studies on the use of dry heat to decontaminate niger seed (Guizotia abyssinica) infested with dodder seed (Cuscuta sp.)” by Strasser, E.G. Way to go, George!
George retired from the USDA in 1992 and resides with June, his wife of 44 years. He hails from New Jersey where he enjoys gardening, feeding the birds and sometimes sings bass for his church choir. Thank you, George, for the time you spent giving me the information for this story—I was delighted to write it!
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