Nyjer seed: the finch specialist that goes stale before you finish the bag

The short answer

• Nyjer is the seed of Guizotia abyssinica, an African and Indian oilseed daisy. It is not thistle, and it will not seed your lawn with thistles.
• Every bag sold in the United States is heat-sterilized before it clears import so it cannot germinate. That heat starts the clock on an oily seed, which is why old nyjer is such a common problem.
• When finches stop feeding, test the seed before you change anything else: crush a dozen seeds on white paper and look for an oil stain within a minute. No stain means no meal.
• Buy in quantities you will use within four to six weeks, not the biggest bag on the shelf. Nyjer is already the most expensive way to buy a calorie in the seed aisle, and a stale bag costs you all of it.
• Only three species rate nyjer as a top-tier food in our dataset: American Goldfinch, Lesser Goldfinch and Pine Siskin. Fourteen species will not touch it.

Nyjer is the seed of Guizotia abyssinica, a yellow daisy grown as an oilseed crop in Ethiopia, India and Myanmar. It is small, black, glossy, about 1/8 in long, and roughly 35% oil by kernel weight. Goldfinches, siskins and redpolls open it with a bill built for exactly that job. Almost nothing else at the feeder can be bothered.

It is not thistle. It has never been thistle. The name is a piece of seed-trade shorthand that survived into the twenty-first century because goldfinches also eat native thistle, and it causes real confusion: people either refuse to buy it in case it seeds their lawn, or they buy it expecting the birds that eat thistle heads in a roadside ditch. Neither worry survives contact with how the seed actually reaches you.

Sterilization: the step that shapes everything else#

Nyjer is imported. It arrives from farms that also grow, or sit next to, plants on the US noxious weed list, and the shipments have historically carried dodder seed as a contaminant. So the seed is heat-treated before it clears import. The treatment kills the embryo. What you buy cannot germinate, which is why spilled nyjer never produces a plant and why nothing regrows under a long-standing finch feeder.

That is good news for your lawn and bad news for your seed.

This is the single fact that separates nyjer from every other seed on the shelf. A sack of black oil sunflower sitting in a shed for a year is still mostly fine, because each seed is sealed inside its own hull and was never cooked. Nyjer has had its clock started for it.

What stale nyjer looks like, and the two tests that settle it#

Old nyjer does not announce itself. The husk stays black and shiny long after the kernel inside has dried to a yellow flake with no oil left in it. A feeder full of seed that looks perfect can be delivering nothing worth eating.

Two tests, both taking under a minute:

1. The paper test. Tip a dozen seeds onto a white paper towel or a sheet of printer paper. Crush them under the flat of a knife or a thumbnail. Fresh nyjer leaves a translucent oil stain spreading out around the crushed seed within about sixty seconds. Stale nyjer leaves dust and a faint gray smear.
2. The kernel test. Split five or six seeds and look at the inside. Fresh: plump, cream to pale gray, slightly greasy on the fingertip. Stale: shrunken, yellowed or tan, dry, sometimes hollow.

Do the paper test on the bag before you buy where you can, and again on the seed already in the feeder when the finches thin out. It answers the question that four forum threads will not.

"The finches stopped eating my nyjer"#

This is the most common complaint about the seed, and it has four causes that need checking in a specific order, because two of them cost nothing to fix.

Step 1: is the feeder actually delivering? Damp fines pack into the slit ports and set. The tube looks full. Nothing comes out. Tap a port and watch: seed should move down to replace what falls. If it does not, the column is caked and the birds gave up on a feeder that stopped working, not on the food. Empty it, brush it, dry it fully.

Step 2: is the seed fresh? Run the paper test. If there is no oil, replace the seed, and do not top up over the old stock. See how to clean a bird feeder for the wash between fills.

Step 3: is there better food twenty feet away? Goldfinches abandon feeders in midsummer when seed heads ripen locally, and they come back when those run out. This is normal and temporary. Do not respond by buying a bigger bag.

Step 4: has the flock left? Pine Siskins are irruptive. A yard mobbed by siskins one winter can see none at all the next, and that has nothing to do with your seed. If the goldfinches are still around but ignoring the tube, go back to step 2.

The economics argue for small bags#

Using our own food dataset, nyjer works out at roughly $3.95 per pound of edible kernel once the 14% husk weight is taken off, and about 591 kcal delivered per dollar spent. That is the lowest energy return of any common seed. Sunflower hearts, for comparison, deliver around 1,019 kcal per dollar, and black oil sunflower about 1,472 kcal per dollar even after you write off the hulls. The full working is in cost per calorie.

You are not buying nyjer for value. You are buying it for the three species that treat it as a first-choice food and for the fact that a nyjer feeder is almost never raided by a grackle or a jay. That is a legitimate reason. It just means the bag should be small enough to finish while it is still worth eating.

The rule we use is the same one on best bird seed: estimate weekly consumption, multiply by six, buy no more than that at once. If a sock empties in eight days, a 3 lb bag is about right. Anything larger is a bet that the seed will outlast the season, and it usually loses.

Storing what you have opened#

Nyjer wants three things: cool, dark, sealed. In that order.

• Decant the bag into a rigid airtight container the day you open it. Paper sacks breathe, and breathing is oxidation.
• Keep it under about 70 °F. A garage in August is the worst place in the property. An unheated basement or a north-facing cupboard is better.
• For anything you will not use inside a month, the freezer works and does not harm the seed. Bring it up to air temperature before filling so condensation does not form on cold seed.
• Never return seed from the feeder to the storage container. It has been rained on.

General principles for the rest of the shelf are in storing birdseed.

Feeders, and the one substitution worth knowing#

Nyjer needs a port sized for it: a slit roughly 1/8 in wide, or a fine mesh. Put it in a standard sunflower tube and it will pour out of the ports onto the ground within a day. The trade-offs between the two common designs are covered in nyjer sock versus nyjer tube, and the feeder types themselves in nyjer and finch feeders.

If you want goldfinches and do not want to run a second feeder and a second seed, there is a clean substitution: sunflower hearts. Goldfinches, siskins and house finches all rate hearts as highly as nyjer, hearts deliver about 70% more calories per dollar, and every other small bird in the yard eats them too. The cost is that hearts are open to grackles and house sparrows in a way nyjer is not. Choose on which problem you have.

Who actually eats it#

• Top-tier favorite for: American Goldfinch, Lesser Goldfinch, Pine Siskin
• Eaten readily by: House Finch, Purple Finch, Dark-eyed Junco
• Taken occasionally by: Black-capped Chickadee, Red-breasted Nuthatch, Mourning Dove, White-throated Sparrow, Song Sparrow

The list is short and it is meant to be. Fourteen of the 34 species in our dataset will not take nyjer at all, and among the ones that will, the dividing line is bill shape rather than size. Note the Dark-eyed Junco sitting higher in that list than most people expect: juncos will work spilled nyjer off the ground under a finch feeder all winter, which is a good argument for hanging one over bare earth rather than over a deck.

If your feeder has never attracted a finch at all, rather than having lost them, the seed is probably not the problem. Start with no birds at my feeder and work through placement and cover first, then come back to which seed to buy.

Frequently asked questions#

Is nyjer the same as thistle seed?

No. Nyjer is the seed of Guizotia abyssinica, a yellow-flowered oilseed crop grown mainly in Ethiopia, India and Myanmar. It picked up the name thistle in the North American seed trade because goldfinches eat both, and the name stuck. Real thistle seed is not sold as bird food. The confusion matters because people worry that spilled nyjer will seed thistles into the lawn. It cannot: the seed is heat-treated before import and is not viable.

Why did my finches suddenly stop eating nyjer?

In order of likelihood: the seed has gone stale, the ports have caked with damp fines so the feeder is not delivering, or the flock has genuinely moved on. Test the seed first by crushing a few on white paper and looking for an oil mark. Then tip a spoonful out of a port and see whether fresh seed slides down to replace it. Only after both pass should you assume the birds left, which does happen in midsummer and after an irruption year ends.

Does nyjer go bad?

Yes, faster than any other seed people buy in bulk. It is roughly 35% oil by kernel weight, and the sterilization heat it receives before import has already pushed it partway down the oxidation path. In a warm garage an opened bag is past its useful life in about six weeks. It does not look obviously bad when it goes: the husk stays black and shiny while the kernel inside shrivels to a dry yellow flake.

How much nyjer should I buy at a time?

Enough for four to six weeks. Work out roughly how fast your feeder empties, then buy that. A single small tube holding half a pound that gets emptied weekly needs about a 3 lb bag per season stretch, not a 20 lb sack. The bulk discount on nyjer is real but it is almost always cancelled out by the last third of the bag going stale and being refused.

Can I put nyjer in a regular tube feeder?

No. Nyjer is about 1/8 in long and pours straight through a 3/8 in sunflower port. You will empty a feeder onto the grass in a day. It needs either a tube with slit ports sized for it or a fine mesh sock. If you want goldfinches on a feeder you already own, fill it with sunflower hearts instead: goldfinches rate hearts as a top-tier food too, and hearts cost far less per calorie delivered.

Why is nothing growing under my nyjer feeder?

Two things are happening. The discarded husks pile up in a dense oily mat that smothers grass, and the seed itself is sterile so nothing germinates to replace what dies. This is normal and it is not a sign of contamination. Move the feeder a few feet each season, or hang it over a hard surface or a mulched bed and rake the husks out periodically.

Sources and further reading

1. Feeding Birds Cornell Lab of Ornithology, Project FeederWatch Which species take nyjer, the feeders it suits, and cleaning intervals and wet seed handling
2. Bird Feeding and Care National Audubon Society General seed selection and feeder guidance
3. Animal and Plant Health Inspection Service United States Department of Agriculture Import treatment requirements for seed carrying noxious weed contaminants