Feeder Types
Caged and Selective Feeders
One dimension decides everything about a caged feeder. Get the grid and the standoff distance right and you have the most selective feeder available; get either wrong and you have an expensive cage that nothing is excluded by.
The short answer
- The working grid is roughly 1.5 inches (4 cm) square. Wider than about 2 inches and starlings get through; narrower than about 1.25 inches and you start losing woodpeckers.
- Admitted: chickadees, titmice, finches, siskins, nuthatches, downy woodpeckers, juncos and wrens. Excluded: grackles, starlings, jays, doves, most squirrels, and cardinals.
- Losing cardinals is the real cost. There is no grid size that admits a cardinal and excludes a grackle, because they are close in size.
- Standoff distance matters as much as grid size: the cage needs to sit at least 2 inches (5 cm) clear of the ports, or a grackle simply reaches through.
- Chipmunks and red squirrels pass through a 1.5 inch grid easily, so a cage is a large-squirrel and large-bird solution only.
The usable number is a grid of roughly 1.5 inches (4 cm) square. A chickadee, titmouse, house finch, goldfinch, nuthatch, junco, wren or downy woodpecker passes through that opening without hesitating. A grackle, starling, blue jay, mourning dove or adult gray squirrel does not.
That single dimension is the entire technology. Everything else about a caged feeder is packaging around it.
The tradeoff is real and worth stating up front: the same grid that stops grackles also stops northern cardinals. There is no clever spacing that separates the two, because a cardinal and a grackle are not far apart in body width. Anyone selling you a cage that admits cardinals is selling you a cage starlings can also use.
Who gets in and who does not#
| Species | 1.5 in (4 cm) grid | Notes |
|---|---|---|
| Black-capped chickadee | In | Passes through without slowing down |
| Tufted titmouse | In | Comfortable, though it prefers to grab and leave |
| American goldfinch, house finch, siskin | In | Easily |
| White-breasted nuthatch | In | Often feeds from the underside of the cage |
| Downy woodpecker | In | Fits; the larger hairy woodpecker is marginal |
| Dark-eyed junco, wrens, sparrows | In | Includes house sparrows, which is a drawback |
| Northern cardinal | Out | The main loss |
| Common grackle, red-winged blackbird | Out | The main gain |
| European starling | Out at 1.5 in, in at 2 in | Grid tolerance is tight here |
| Blue jay, doves, grosbeaks | Out | Feed these on an open tray instead |
| Gray squirrel | Out | Adults only; young squirrels sometimes fit |
| Chipmunk, red squirrel | In | Cages do nothing about either |
Two entries deserve a second look. The hairy woodpecker sits right at the limit: some individuals work their way through a 1.5 inch grid and some give up, so do not count on it either way. And young gray squirrels in late summer are small enough to slip in for a few weeks before they bulk up, which is why a cage that seemed squirrel-proof in June sometimes fails in August.
The tight margin is starlings. A European starling is a determined, flexible bird, and the difference between a grid it cannot use and one it can is a matter of half an inch. Measure the grid on any feeder before buying rather than trusting the description.
Standoff distance: the number nobody prints#
Grid size is only half the geometry. The other half is how far the cage sits from the food.
A grackle that cannot get its body through the wire will still put its head and neck through and reach. If the cage sits an inch from the seed ports, that is enough. The cage needs at least 2 inches (5 cm) of clear space between the wire and any point a bird can feed from, and 3 inches (7.5 cm) is better.
This is the most common fault in cheap caged feeders: a cage shrink-wrapped around the tube so tightly that it excludes squirrels and nothing else. Hold the feeder up and check whether you could get a finger through the wire and touch a port. If you can, a grackle can eat.
Two dimensions, both required
A caged feeder works only if the grid is about 1.5 inches (4 cm) and the wire stands 2 to 3 inches (5 to 7.5 cm) off the feeding surface. Either one alone gives you a feeder that looks selective and is not.
The three cage formats#
Cage-around-tube. A wire cylinder surrounding a conventional tube feeder, usually removable. The most versatile format, because you can take the cage off in seasons when blackbirds are absent and let the cardinals back in.
Integrated cage feeders. The wire is the structure, with a seed chamber inside. Fewer parts to lose, generally sturdier, but you cannot un-cage it.
Caged suet and peanut feeders. A suet cage or peanut mesh inside a wider wire box. This is the strongest starling deterrent that exists for suet, and it matters because starlings can strip a suet cake in a morning. The alternatives, including upside-down designs, are compared in suet feeders.
Build your own for the price of the wire
Galvanized welded wire with 1.5 inch (4 cm) openings, rolled into a cylinder around a tube feeder and closed top and bottom with hardware cloth discs, does exactly what a manufactured cage does. Fold or file every cut end. A projecting wire snag is a genuine injury risk to a bird landing at speed, and it is the one part of the job worth being fussy about.
What a cage does not solve#
Cages are size filters, so anything small enough to be a problem stays a problem.
House sparrows walk straight through a 1.5 inch grid. So do chipmunks, and so do red squirrels, both of which can clear a feeder faster than a gray squirrel can. Cages also do nothing about seed spoilage, nothing about disease transmission on a crowded perch, and nothing about a squirrel sitting on top of the cage and raking seed out through the ports it can reach.
They are also no substitute for pole geometry. A caged feeder hanging from a branch within 10 feet (3 m) of a launch point still gets squirrels on it, chewing, and the seed still ends up on the ground. The baffle and pole argument is in squirrel-proof feeders and in more detail in how to stop squirrels raiding feeders.
Where a caged feeder is the right answer#
Three situations justify one.
A blackbird takeover. If grackles and blackbirds arrive in spring flocks and empty the feeders in two days, a cage ends it immediately. Nothing else is as fast.
A starling problem at suet. Caged or upside-down suet is the standard fix, and it is discussed alongside the other tactics in keeping starlings off feeders.
Small-bird specialists. If what you want is a chickadee and titmouse feeder that stays available all day rather than being monopolized, a cage delivers it. The same logic drives the advice in how to attract chickadees and the equivalent guidance for titmice.
There is a fourth, narrower case: painted buntings in the South, where a caged millet feeder keeps house sparrows and doves from clearing the seed before the buntings arrive.
Keeping cardinals despite the cage#
The workaround is not a different grid, it is a second feeder.
Run the caged feeder for the small birds, and give cardinals a separate hopper or tray filled with safflower. Grackles and starlings largely avoid safflower seed, cardinals eat it readily, and the combination gets you selective feeding across both size classes without compromise on either.
Space the two feeders several yards apart so the excluded birds do not crowd the caged one out of frustration. Spacing guidance is in how many feeders and how far apart.
Wire ends and wet perches
Two welfare points specific to cages. First, check for broken or protruding wires each fall; galvanized wire fatigues at the welds and a snapped end at bird height is sharp. Second, a cage keeps more birds feeding in one small volume for longer, which concentrates droppings on the perches. Caged feeders need cleaning at least as often as open ones, on the schedule in how often to clean bird feeders.
Setting one up#
- Measure the grid. Anything near 2 inches (5 cm) will admit starlings.
- Check the standoff: 2 to 3 inches (5 to 7.5 cm) between wire and ports.
- Fill with black oil sunflower or sunflower hearts. Small birds are the whole audience, so shell-free seed reduces mess under a feeder that already drops more than most.
- Mount on a baffled pole, not a branch.
- Add a safflower tray elsewhere for the cardinals you have just excluded.
- Take the cage off in midsummer if blackbirds have moved on, then refit it before the fall flocks build.
That last habit is the advantage of the removable format, and it is why a cage-around-tube is usually the better buy over an integrated one.
Frequently asked questions#
What size should the grid be on a caged bird feeder?
About 1.5 inches (4 cm) square. That is the standard for a reason: it is wide enough for chickadees, titmice, finches, nuthatches and downy woodpeckers to pass through comfortably, and narrow enough to stop grackles, starlings, jays and adult gray squirrels. Grids of 2 inches (5 cm) or more let starlings squeeze in.
Do caged feeders keep cardinals out?
Yes, and that is the main drawback. A northern cardinal is too broad-bodied for a 1.5 inch (4 cm) grid, and no grid size separates cardinals from grackles because the two birds are similar in bulk. If you want both cardinals and blackbird exclusion, run a caged feeder for the small birds and a separate safflower feeder for the cardinals.
Do caged feeders stop squirrels?
They stop adult gray squirrels from reaching the seed, which is most of the problem. They do not stop chipmunks or red squirrels, which fit through a 1.5 inch (4 cm) grid, and they do not stop a squirrel from chewing the feeder or sitting on the cage flicking seed out. The cage is one layer; a pole and baffle are still the foundation.
Can I make a caged feeder myself?
Yes. Galvanized welded wire fencing with 1.5 inch (4 cm) openings, formed into a cylinder around an existing tube feeder and capped top and bottom, works as well as a bought one. Leave at least 2 inches (5 cm) between the wire and the feeding ports, and file or fold every cut wire end so no bird can catch a foot or a wing on it.
Will a caged feeder keep house sparrows out?
No. House sparrows are small enough to pass through a 1.5 inch (4 cm) grid without difficulty, so a cage does nothing about them. Sparrow control depends on seed choice, feeder type and persistence rather than exclusion by size.
Are caged suet feeders different from caged seed feeders?
Only in the food, not the principle. A caged suet feeder is a standard suet cage inside a wider wire box, and it is the most effective starling deterrent available for suet. Upside-down suet feeders work on the same logic by demanding a clinging posture starlings hold poorly.