Birdseed mixes: how to read the label and do the arithmetic

The short answer

• Ingredients are listed by weight, heaviest first. If sunflower is not in the first two entries, you are buying grain with sunflower sprinkled on it.
• Milo, red millet, wheat, oats, canary seed and flax are refused by most feeder birds east of the Rockies. White proso millet and cracked corn are not filler, they are ground-feeder food in the wrong feeder.
• A bargain mix of which only a fifth is ever taken from the feeder costs roughly five times its shelf price per pound that reaches a bird. Straight sunflower is taken in full.
• Mixes are genuinely right in one place: an open ground or platform station feeding sparrows, juncos, doves and towhees, where millet, corn and sunflower are all wanted.
• Two seeds cover almost every North American yard: sunflower in the hanging feeders, white proso millet on the ground.

Every bag of mixed birdseed is a proposition: that a packer's blend matches the birds in your yard better than you could match them yourself. The ingredient list tells you whether it does, and it takes about ten seconds to check.

Read the ingredient list before anything else#

Seed mixes list ingredients by weight, heaviest first. That single fact does most of the work.

• Look at the first two entries. They usually account for the majority of the bag. If those two are sunflower, or millet and sunflower, the mix has a real audience. If they are milo, sorghum, wheat, corn or oats, you are buying grain.
• Treat unnamed categories as a warning. "Grain products", "processed grain by-products" and "seed by-products" mean the packer reserves the right to change what is in there. You cannot evaluate a bag whose contents are described as a category.
• A bag with no ingredient list at all is not a candidate. There is no reason to guess.
• Ignore the picture. Cardinals on the label do not indicate cardinal food.

One more physical check: milo and corn are dense and settle. If a bag has been sitting on a pallet, the top of it looks better than the bottom. Judge from the bottom.

The filler seeds, and who each one is really for#

"Filler" is shorthand for "cheap per pound and refused by the birds at your feeder". It is not a property of the seed alone, it depends on region and on where the seed is offered.

Regional honesty matters here. Milo genuinely has takers in the desert Southwest where Gambel's Quail and doves work a ground station, and dismissing it outright is an eastern habit. Everywhere else it is ballast.

Two seeds get wrongly grouped with the fillers and should not be: white proso millet and cracked corn. Both are top-tier foods for ground-feeding birds. They only behave like filler when they are loaded into a hanging feeder used by birds that want sunflower.

Top top-tier favorite Yes eats readily Some takes occasionally Rare rarely No not a feeder food

Read that grid across rather than down. The chickadee and goldfinch rows are a sunflower and nyjer story. The junco, dove and sparrow rows are a millet and corn story. The cardinal sits in both. A bag that mixes those foods together is trying to serve two feeding guilds that do not use the same feeder, which is the structural problem with mixes in one sentence.

The arithmetic: why the cheap bag costs more#

Price per pound bought is the wrong number. The number that matters is price per pound eaten.

Take a typical bargain mix. A representative composition by weight looks something like this. The filler grains are not in our seed dataset, so treat the bag price below as a working assumption rather than a benchmark figure, and substitute the price on your own shelf:

At a tube or hopper feeder used by chickadees, titmice, nuthatches, finches and cardinals, the sunflower is eaten and roughly half the white millet gets picked at by cardinals and House Finches. Call it 20% consumption, which is generous.

• Cost per pound bought: $0.85
• Fraction taken from the feeder: 0.20
• Cost per pound taken: 0.85 / 0.20 = $4.25

Now the same sum for straight black oil sunflower at about $1.35 a pound, essentially all of which is taken by that same crowd:

• Cost per pound bought: $1.35
• Fraction taken from the feeder: 1.00
• Cost per pound taken: $1.35

Note what this sum is and is not. It measures sorting waste, the seed that gets flicked onto the ground uneaten. Hull waste sits on top of it and is a separate calculation: after the shell, black oil works out nearer $1.80 a pound genuinely eaten, which is the figure used everywhere else on this site and is derived in best bird seed. Either way the mix loses, and by more than the shelf price suggests.

Scale that to a season. Suppose your feeders get through 10 lb of seed that birds actually eat per month, which is a moderately busy suburban station in winter.

Two things that arithmetic leaves out, both of which make the mix look worse:

Hulls are a separate layer. Black oil sunflower is about 75% kernel by weight, so a pound of it delivers roughly 0.75 lb of food and 0.25 lb of hulls. That is a real cost and a smaller one than sorting waste, which is why sunflower hearts at around twice the price per pound stay dearer than in-shell seed even after the hull comes off. A hull is packaging that the bird opens and drops. Rejected milo is food nobody wanted, dropped whole.

Forty pounds of grain on the ground is a cost. It sprouts, it mats down and kills the lawn, it goes moldy in wet weather, and it feeds rats and mice you did not intend to feed. See seed waste and mess for what that actually turns into.

When a mix is genuinely the right answer#

There is one, and it is not a compromise.

An open ground tray or a low platform feeding doves, juncos, White-throated and Song Sparrows, towhees, cardinals and jays wants variety, because those species split across different foods. Millet, sunflower and cracked corn are all first or second-choice for someone in that group, and nothing gets swept aside to reach something else because there is no sorting pressure on a flat open surface: a bird simply steps past what it does not want and another bird eats it.

Run the same sum for that situation with the bargain mix. On the ground, the millet, corn and sunflower all find a taker, so about 45% of the bag is eaten: $0.85 / 0.45 = $1.89 per pound eaten. Better, and still beaten easily by a blend you make yourself:

• 50% white proso millet at about $1.10/lb
• 30% black oil sunflower at about $1.35/lb
• 20% cracked corn at about $0.75/lb

That comes to about $1.11 per pound, with essentially nothing rejected. Mix it in a clean bin, keep it dry, and put it out in the quantity that gets cleared before dark on a ground feeder.

Build a two-seed system instead#

For most yards the whole mix question dissolves once you separate the feeders by guild.

1. Seed one, up high. Black oil sunflower in the tube, hopper and window feeders. Over a deck or patio, use hearts instead so there is nothing to sweep up. This covers chickadees, titmice, nuthatches, finches, cardinals, grosbeaks and woodpeckers.
2. Seed two, down low. White proso millet on a ground tray or low platform, with cracked corn added in winter if you want jays and doves. This covers juncos, sparrows, doves and towhees.
3. Optional third seed, by problem. Nyjer if you specifically want goldfinches and siskins in a dedicated feeder. Safflower in place of sunflower if grackles or squirrels have taken over.

Two straight seeds cost less than one mid-range mix, waste nothing, and let you change one variable at a time when something is not working. The head-to-head case is laid out in seed mix versus single seed, and the wider question of what to buy first is in which seed to buy.

If you already own a bag of it#

Do not throw it out. Sieve it or simply pour it onto a ground tray in small amounts and let the ground crowd take what they want, clearing the residue every few days so it does not mat and mold. Alternatively, use it up in a hopper positioned over bare soil or gravel rather than lawn, where the rejected fraction can be swept.

What you should not do is store it badly on the assumption it will keep. Grain-heavy mixes carry more moisture and attract more pantry moths and weevils than straight sunflower. Keep it in a sealed metal or hard plastic bin somewhere cool and dark, and check it before every fill, using the routine in storing birdseed.

Frequently asked questions#

What is milo and why is it in bird seed?

Milo is grain sorghum: hard, round, reddish-brown seeds about the size of a peppercorn. It is in mixes because it is cheap and heavy, so it fills a bag for very little money. East of the Rockies almost no feeder bird eats it, and it gets swept out of feeders onto the ground where it sits and sprouts. In the Southwest it has a genuine audience, with quail and some doves taking it on the ground. If you are not in that region and milo is high on the ingredient list, put the bag down.

Is white millet a filler?

No, and this is the most common mistake in the filler conversation. White proso millet is a top-tier food for Mourning Doves, Dark-eyed Juncos, White-throated and Song Sparrows and House Sparrows, all of which rate it as highly as chickadees rate sunflower. What makes it look like filler is the feeder, not the seed. Millet in a hanging tube gets flicked onto the ground by birds that do not want it. The same millet on a ground tray disappears. Red millet is a different seed and is largely refused.

Why is my mixed seed piling up under the feeder?

Birds are sorting. A bird that wants sunflower will use its bill to sweep aside every seed that is not sunflower to reach it, and in a tube or hopper that means everything unwanted lands underneath. The pile is a physical measurement of how much of the bag your birds do not eat. Weigh a week's worth of it if you want the exact number. The fix is not a bigger tray under the feeder, it is filling the feeder with a seed the visitors actually take.

Is expensive bird seed worth it?

Judge it per pound eaten, not per pound bought. Take a bargain mix at roughly $0.85 a pound where a hanging-feeder crowd eats maybe a fifth of it: that is $4.25 per pound actually consumed, plus a mound of grain on the ground. Take straight black oil sunflower at roughly $1.35 a pound, essentially all of which is taken rather than sorted out. Per pound that actually reaches a bird, the dearer bag is several times cheaper. Hulls are a separate layer on top of that, worked through in best bird seed. This holds until you get into premium blends full of dried fruit and nuts, where you are usually paying for things that look good to humans.

What should be the first ingredient in a bird seed mix?

Sunflower, in one of its forms: black oil sunflower, sunflower hearts or chips. For a mix intended for ground feeding, white proso millet as the first ingredient with sunflower second is also sound. What you do not want to see first is milo, sorghum, wheat, cracked corn, oats or any unnamed category such as grain products. Ingredients are listed by weight in descending order, so the first two entries usually account for most of what is in the bag.

Can I just make my own mix?

Yes, and it is cheaper and better than almost anything pre-blended. For an open ground station, 50% white proso millet, 30% black oil sunflower and 20% cracked corn by volume covers doves, juncos, sparrows, towhees, jays and cardinals, and comes out around $1.10 a pound with nothing rejected. Buy the components as straight seed in the largest bags you can store properly, and mix in a clean bin. Do not put this blend in a tube feeder: it is a ground and platform mix by design.

Sources and further reading

1. Feeding Birds: Types of Bird Food Cornell Lab of Ornithology, Project FeederWatch Seed preferences by species and the standing of milo and other fillers
2. The Best Bird Seed for Your Backyard Birds National Audubon Society Sunflower and millet as the core feeder seeds
3. Attracting Birds to Your Backyard Cornell Lab of Ornithology, All About Birds Feeder and seed matching
4. Backyard Bird Feeding U.S. Fish and Wildlife Service General feeding guidance and seed choice