Suet feeders: cages, tail props and the upside-down trick

The short answer

• A suet cage is the best value addition to a seed station: ten species in our dataset rate suet as a top-tier food, including every woodpecker, both nuthatches, chickadees, titmice and Carolina Wren.
• A tail-prop extension gives woodpeckers a surface to brace their stiff tail against, which turns short awkward visits into long settled ones. Downies and Hairies want 5 to 7 in below the cake; a flicker wants 9 in or more.
• An upside-down suet feeder, with the cake accessible only from below, is the most reliable non-chemical way to keep starlings off suet while letting woodpeckers, nuthatches and chickadees feed normally.
• Suet fails by going rancid, not moldy. Fat has too little water for mold, but it oxidises, and the greasy film left in an unwashed cage turns rancid faster than the cake does.
• Plain rendered suet slumps out of a cage in summer heat. Above roughly 85 to 90 °F, switch to a no-melt dough or take the feeder down until autumn.

Add a suet cage to a seed station and the yard list grows faster than for any other purchase. Ten of the 34 species in our dataset rate suet as a top-tier food, and the group is almost entirely birds a tube feeder does not serve well: every woodpecker we track, both nuthatches, chickadees, titmice and the Carolina Wren.

• Top-tier favorite for: Black-capped Chickadee, Tufted Titmouse, White-breasted Nuthatch, Red-breasted Nuthatch, Downy Woodpecker, Hairy Woodpecker, Red-bellied Woodpecker, Northern Flicker, Carolina Wren, European Starling
• Eaten readily by: Blue Jay, Eastern Bluebird, Steller's Jay, California Scrub-Jay, Common Grackle
• Taken occasionally by: Northern Cardinal, American Robin, Baltimore Oriole, House Sparrow, Red-winged Blackbird

At roughly 740 kcal per 100 g, suet is the most energy-dense thing you can put out, which is why it earns its place in a February cold snap far more than in July.

The cage is a wire box, and the details are not cosmetic#

Nearly all suet feeders are a hinged cage of vinyl-coated wire sized to a standard cake of about 11 oz. Within that, the variations change who feeds and for how long.

Vinyl coating on the wire matters more than it sounds. In freezing weather bare metal is harsh on feet and tongues, and coated wire is also easier to degrease. Check the hinge and the clasp too: a spring clip that a raccoon can work open is the reason many people find the whole cage gone in the morning, and raccoons are considerably better at latches than most feeder designers assume.

Tail props, and why woodpeckers care#

Woodpeckers do not perch to feed. They cling, and they brace: the stiff central tail feathers press against the trunk and form the third leg of a tripod, which is what lets a bird hammer at a vertical surface without swinging off it. Take that bracing surface away and the bird has to hold itself on with feet alone against a cage that moves whenever it does.

They will still feed. They just do it in short, unsettled bursts, and they lose more of them to disturbance.

A tail prop is simply a flat panel extending below the cake so the tail has something to press on. Sizing follows the bird:

• Downy Woodpecker, 27 g, and Hairy Woodpecker, 62 g: about 5 to 7 in of surface below the bottom of the cake.
• Red-bellied Woodpecker, 72 g: 7 in or more.
• Northern Flicker, 130 g: 9 in and up, and it wants a wide panel, not a narrow tongue. This is the bird most often defeated by a standard cage.

The upside-down feeder as a starling filter#

Starlings are the reason most people give up on suet. They arrive in numbers, they rate suet as a top-tier food in our dataset just as woodpeckers do, and a flock can strip a cake in a morning.

The exclusion that works is postural, not mechanical. In an upside-down feeder the cake sits behind a solid roof and is reachable only from the underside, so a bird has to hang beneath the feeder to eat. Woodpeckers, nuthatches, chickadees and titmice all do this routinely: nuthatches habitually work head-down on trunks, and woodpeckers have no difficulty gripping under an overhang. A European Starling, at 82 g with feet built for walking on turf, can manage it briefly and will not keep it up.

What to expect when you switch:

1. Days 1 to 3: starlings hover, land on top, cling to the sides, and mostly fail. Your woodpeckers may also hesitate, because the approach has changed.
2. Days 4 to 7: woodpeckers and nuthatches work it out and settle. Starling attempts fall away sharply.
3. After that: the feeder is effectively starling-free, with occasional persistent individuals.

Two things make it work faster. Use plain suet rather than peanut, fruit or berry blends, which are the most attractive to starlings. And stop putting anything on the ground nearby, since a flock that is already in the yard will keep testing the feeder. The broader campaign is in dealing with starlings, and the exclusion principle generalizes to caged and weight-activated feeders.

Heat: the number that ends suet season#

Rendered suet is fat, and fat has a softening range rather than a sharp melting point. As a practical threshold, plain rendered cakes start to slump around 85 to 90 °F and are unusable in direct summer sun. What follows is worse than waste:

• The softened cake extrudes through the cage mesh and drops onto the ground, where it goes rancid and draws ants, wasps and rodents.
• Melted fat coats the wires, so every bird that lands gets greasy.
• Fat on the head and breast feathers of a feeding bird is a genuine problem, particularly for adults carrying food back to nestlings during the breeding season.

No-melt dough is the summer answer: suet with flour, cornmeal or similar worked in, which holds its shape into the high 90s. It is not a license to ignore the weather. Put it in shade, put out half a cake at a time so it turns over in days rather than weeks, and check it every couple of days.

Or take the feeder down between late spring and early autumn. Insects are abundant then and suet is the least interesting thing on offer, which is why so many people report their suet feeder being ignored in July. See summer bird feeding for the seasonal picture, and suet for birds for what the different cake formulations actually contain.

Rancid, not moldy#

Almost every other feeder food fails by getting wet and growing mold. Suet does not, because rendered fat has too little available water for mold to establish. Suet fails by oxidising.

Heat, light and air turn fat rancid. Rancid suet smells sharp and stale rather than musty, it looks faintly yellowed and waxy at the edges, and birds simply stop coming to it. There is no visible fuzz to tip you off, which is why the failure is so often misread as "the birds have gone elsewhere".

The cage is usually further gone than the cake. Every cake leaves a film of fat on the wires, and that film is thin, exposed to air on all sides, and heats up in the sun. It oxidises much faster than the block does. A greasy cage that has not been washed in a season will put birds off a perfectly fresh cake.

The routine:

1. Every second cake, take the empty cage inside.
2. Wash in water as hot as your hands will take, with dish detergent. Detergent is doing the work here, because this is grease, not dirt. Cold water will not touch it.
3. Scrub the wire with a stiff brush, including the hinge and the clasp.
4. Rinse, dry fully, and only then load a new cake.
5. Add the standard disinfection step on the cage's normal cleaning interval, every three to four weeks in cold dry weather and every two weeks in heat. Method in how to clean a bird feeder.

Store spare cakes cool and dark, and in warm months in the freezer. Suet keeps almost indefinitely frozen and deteriorates quickly on a shelf in a hot garage. If you make your own, homemade suet recipes covers rendering and storage.

Placement: the trunk problem#

Woodpeckers, nuthatches and creepers arrive on trunks. They work up a tree, they check bark, and a suet cage mounted flat against a trunk or on a slab a few feet up sits exactly where they are already looking. Trunk placement also gives the bird a bracing surface for free, which is a tail prop without buying one.

The problem is that a trunk is a road. Squirrels come down it, and so do raccoons, and neither can be baffled off a tree the way they can off a pole.

Three workable arrangements:

• Trunk-mounted with a dome above. Best behavior from the birds, but the dome has to be wide and it does not stop anything climbing from below.
• Pole-mounted with a baffle, sited within 10 to 15 ft of a trunk. The common compromise: woodpeckers will cross that gap readily, and the mammal problem is solved properly by baffles and poles.
• Hung from a branch with a long dome baffle above. Workable, but the cage swings, which is the exact thing a tail prop is trying to fix.

Whichever you pick, put it at eye level or slightly above, on the side of the trunk or pole facing your window. These are among the most watchable birds in the yard, and they will tolerate close observation as long as there is cover within about 10 ft.

If woodpeckers are your target, run a suet cage and a peanut feeder together. Downies, Hairies and Red-bellieds all rate shelled peanuts as highly as suet, and two feeders side by side hold them in the yard for far longer than one. Where suet fits in the overall build order is set out in how to choose a bird feeder.

Frequently asked questions#

What is a tail prop on a suet feeder and do I need one?

It is a flat extension, usually wood, that hangs below the cage so a woodpecker can brace its stiff tail feathers against it and feed in its normal tripod posture. Without one, a woodpecker has to cling to the side of a swinging cage using feet alone, which it can do but not for long. Add a tail prop and visits get longer and calmer. Length matters: allow 5 to 7 in of surface below the cake for Downy and Hairy Woodpeckers, and 9 in or more if you want Northern Flickers.

How do I keep starlings off my suet feeder?

Use an upside-down feeder, where the cake sits behind a solid top and can only be reached from underneath. Woodpeckers, nuthatches, chickadees and titmice all feed hanging or clinging beneath a surface without difficulty. Starlings can hang briefly but will not sustain it, so they give up within a few days. Combine it with plain suet rather than a peanut or fruit blend, and stop scattering food on the ground nearby, and the problem usually resolves in about a week.

Does suet go moldy?

Rarely. Rendered fat holds very little water, so mold struggles to grow on it. What actually happens is rancidity: the fat oxidises in heat, light and air, turning sharp and stale-smelling, and birds start refusing it. The greasy film left on the wires of an unwashed cage goes rancid faster than the cake does, which is why a well-used cage can put birds off perfectly fresh suet. Wash the cage in hot soapy water every second cake.

Can I feed suet in summer?

Only the right kind. Plain rendered suet begins to soften around 85 to 90 °F and will slump through the cage, coat the wires and drip onto the ground, where it goes rancid and attracts ants and rodents. Melting fat can also foul the head and breast feathers of birds feeding on it. Use a no-melt dough, which has flour or cornmeal worked in and holds its shape into the high 90s, put it somewhere shaded, and put out half a cake at a time so it turns over quickly.

Where should a suet feeder be placed?

Against or near a tree trunk if you want the most natural woodpecker behavior, since these birds arrive on trunks and work upwards. A trunk-mounted cage also gives the bird a bracing surface for free. The cost is that a trunk is a highway for squirrels and raccoons, so a trunk mount needs a dome baffle above it or it will be emptied overnight. A pole-mounted cage with a proper baffle is the compromise most yards end up with.

Why has nothing touched my suet?

Work through four causes in order. The suet is rancid, which you can check by smell. The cage is greasy and rancid even though the cake is fresh. The feeder is new and the local woodpeckers have not found it yet, which routinely takes two to three weeks. Or it is high summer, when insects are abundant and suet is the least interesting thing on offer. Move the cage nearer a trunk, wash it, and give it time before changing anything else.

Sources and further reading

1. Feeding Birds: suet and other foods Cornell Lab of Ornithology, Project FeederWatch Suet as a feeder food and which birds take it; Feeder washing routine
2. Downy Woodpecker life history Cornell Lab of Ornithology, All About Birds Clinging and tail-bracing feeding posture
3. Bird Feeding and Care National Audubon Society Placement and cover around feeders