What is emptying my bird feeder at night?

The short answer

• Six animals empty feeders at night in North America: raccoons, opossums, flying squirrels, rats and mice, deer and bears. Gray, fox and red squirrels are daytime animals and are not your night raider.
• The feeder itself is the first clue. On the ground and pried open is a raccoon. Crushed, pole bent flat or carried off is a bear. Hanging and intact on a leaning hook is a deer. Hanging, intact and on a baffled pole is a flying squirrel.
• Rats and mice lower the level slowly, and they leave droppings. ICWDM puts a rat at about half an ounce of grain a day, so a pound gone overnight with no droppings is not rodents.
• One test night settles it: tape the seed level at dusk, smooth a flour patch under the feeder, and shine a light on the feeder an hour or two after dark or leave a motion camera running.
• Taking the feeder in at dusk stops five of the six. A bear is the exception: the feeder comes down for the season.

It is one of six animals: a raccoon, an opossum, a flying squirrel, rats or mice, a deer or a bear. It is not the gray squirrel you see at lunchtime. The Internet Center for Wildlife Damage Management (ICWDM) says it flatly: flying squirrels are active at night, and all other North American tree squirrels are active primarily during the day. The feeder, the pole and the ground under it will tell you which of the six you have, usually before you buy anything.

Two answers circulate about this. One says it must be squirrels, because squirrels empty feeders. The other says it cannot be squirrels, because squirrels sleep at night. The first is wrong about gray, fox and red squirrels and the second is wrong about flying squirrels, which is why people who have already beaten their daytime squirrels are so baffled when the feeder keeps emptying anyway.

The clue table#

Go out at first light, before you refill anything, and read the scene against this.

The track and dropping details are ICWDM's, from its species pages. The "how much went" row is our own reading of what each animal can carry or eat, and it is the clue most people skip.

The one question that splits the list: was the pole climbed?#

If the feeder hangs on a properly baffled pole in open ground and still empties, nothing climbed it. That leaves three suspects: a deer reaching from the ground, a bear going through everything, or a flying squirrel arriving from above. A deer leaves the hook bent and hoof prints in the soil. A bear leaves wreckage. If the feeder is untouched and the ground is clean, it is the glider.

If the pole has no baffle, or the feeder hangs from a branch or a deck rail, the climbers come back into play: raccoons, opossums and rats. ICWDM notes that opossums are not destructive or strong and use openings that already exist, while raccoons make their own. A pried lid and a sprung latch point to a raccoon; an intact feeder with a picked-over tray points the other way.

Flying squirrels: the night raider squirrel hardware misses#

Nothing designed for daytime squirrels touches this one.

• It glides in. Northern Woodlands puts its glide at nearly 300 ft from tree to tree. Compare that with the 7 to 10 ft horizontal jump a gray squirrel manages on the level, which is what every clearance rule in baffles and poles is built against. A feeder 10 ft from the nearest branch defeats a gray squirrel and is an easy landing for a glider.
• It never touches the pole. A baffle stops climbing from below. A glider lands on the feeder or its roof, so the baffle calculator has nothing to say about it.
• It is small. ICWDM gives southern flying squirrels as 8 to 10 in long and northern ones as 10 to 12 in, tail included. A gray squirrel is 16 to 20 in. Hardware sized against the bigger animal, including most squirrel-proof feeders, was never tested against this one.
• It wants the rich food. Northern Woodlands lists sunflower seed and suet. If your suet cake is shrinking overnight on a feeder no raccoon could reach, this is the likely reason.

ICWDM also notes that flying squirrels need large, mature hardwoods. A yard with big oaks, maples or hickories nearby is a candidate; a new subdivision with young street trees is a much weaker one.

The test night#

One night of watching beats a week of guessing. Do all four at once.

1. Tape the level at dusk. Fill the feeder and put a strip of tape at the seed line. If it has dropped by first light, you have a night animal and can stop buying daytime squirrel gear.
2. Lay a flour patch. Smooth a thin layer of flour on a board, a paver or bare soil directly under the feeder. ICWDM uses exactly this overnight patch to detect rodents, and it records any other visitor too. Hand-like prints are a raccoon, a thumb on the hind foot is an opossum, small prints with a tail line are rats or mice, a split hoof is a deer.
3. Look with a light. An hour or two after full dark, walk out and shine a flashlight on the feeder. This is Northern Woodlands' own suggestion: you may find several flying squirrels on it at once, and anything larger is usually plain to see in the beam.
4. Or leave a camera. A motion-triggered camera with an infrared night mode answers the question while you sleep. Frame the feeder and the ground beneath it, because rodents work the ground.

The fix for each culprit#

Five of the six fail against one habit: take the feeder in about 30 minutes before dark and put it back at first light. Birds do not feed in the dark, so you lose nothing. What changes between culprits is what you add to that.

Raccoon. The dusk rule, plus the ground cleared, plus a cylinder baffle at least 8 in across and 24 to 36 in long if the feeder must stay out. Squirrel cones are too short. The full spec and the garbage and compost checklist are in raccoons at feeders.

Opossum. Same dusk rule, and a baffled pole, since it climbs. ICWDM lists bird feeders among the things opossums get into alongside garbage and pet food, so close those too, and keep the ground under the feeder clear: see seed waste and mess.

Flying squirrel. The dusk rule is the only fix that works, and suet should be the first thing in. No pole baffle stops an animal that lands on top. Some people keep one feeder out for them and enjoy the show. If you have nest boxes, check them, since ICWDM notes flying squirrels move into bird houses and eat nestlings.

Rats and mice. ICWDM says Norway rats become active around dusk and seldom travel more than 400 ft from their burrow for food, so a colony feeding under your feeder lives close by and the spill is its real target. Dusk removal, clean ground and seed in a metal can are the basics, and the two-week reset is in rats and mice under the feeder.

Deer. The dusk rule works, but height also works: ports at 7.5 to 8 ft with 5 ft of clear space on every side. Drop cracked corn first, since it is the strongest deer draw in the bag. Check your state's feeding rules too, which deer at feeders explains.

Bear. No fix keeps the feeder out. Bring every feeder in for the season, rake up the spill, and report the visit to your state or provincial wildlife agency. The reasons are in bears and bird feeders, and in some states leaving feeders up after a warning is an offense: see bear feeding laws by state.

Where this diagnosis stops working#

The table assumes one culprit. Two can share a feeder: rats under the tray every night and a raccoon once a week. If the test night shows more than one set of prints, fix the stronger animal first, since its spill feeds the other.

Finally, if the tape line holds overnight and the feeder empties between 7am and 10am, none of this applies. That is a daylight problem, and the problems hub sorts the daytime suspects.

Frequently asked questions#

Can squirrels empty a bird feeder at night?

Only one kind. Gray, fox and red squirrels are active primarily during the day, so a feeder that empties between dusk and dawn is not theirs. Flying squirrels are the exception: they are active at night, glide in from trees up to nearly 300 ft away, and take sunflower and suet. Because they land on the feeder from above, a pole baffle that works perfectly against gray squirrels does nothing to them. If the feeder is intact, still hanging and on a well-baffled pole, a flying squirrel is the first suspect.

How do I find out what is eating my bird seed at night?

Run one test night. Mark the seed level with tape at dusk. Smooth a patch of flour on a board or paving under the feeder, which is the rodent tracking method wildlife damage specialists use. Then either go out an hour or two after dark with a flashlight and look at the feeder, or set a motion camera with an infrared night mode pointed at it. In the morning you have the time window, the footprints and usually a picture.

Will a light keep animals off my feeder at night?

Do not count on it. Lights are useful for seeing what is there, not for driving it away. Northern Woodlands suggests shining a light on your feeders at night precisely because you may then see several flying squirrels feeding, and raccoons and deer in suburbs are used to porch and street lighting. The fix that reliably works is removing the food: take the feeder in at dusk and put it back at first light.

Are flying squirrels at my feeder a problem?

For your seed bill, mildly. For your nest boxes, possibly. ICWDM notes flying squirrels are the most carnivorous of the tree squirrels, eat bird eggs and nestlings, often occupy bird houses and use entrance holes about the size of a quarter. Their droppings have been associated with murine typhus, so wear gloves when you clean a feeder or box they have used. Many people simply enjoy them and bring the suet in at night.

Why did my feeder empty overnight when nothing is damaged?

Three animals take seed without breaking anything. A deer drains a hopper from below and leaves the hook bent or leaning, with cleft hoof prints in soft ground. A flying squirrel lands on the feeder and leaves no trace on the pole. Rats and mice feed at the tray and lower the level slowly, leaving droppings. The amount gone separates them: rodents take ounces, a deer can take the lot.

Sources and further reading

1. Flying Squirrels and Bird Feeders (Mary Holland, Summer 2017) Northern Woodlands Flying squirrels are nocturnal, glide nearly 300 ft, take sunflower and suet; shining a light at night reveals them
2. Tree Squirrels: identification, biology and damage identification Internet Center for Wildlife Damage Management Flying squirrels active at night, all other species by day; flying squirrel lengths; quarter-size holes; nestling predation; murine typhus
3. Identification of Damage to Bird Feeders Internet Center for Wildlife Damage Management Feeders ripped down or severely damaged point to bears or another large mammal
4. Raccoons Internet Center for Wildlife Damage Management Nocturnal; hand-like front prints; climbing smudges; latrines; roundworm
5. Norway Rats and House Mice Internet Center for Wildlife Damage Management Active from dusk; half-ounce daily intake estimate; dropping sizes and clumping; flour tracking patch
6. Opossums Internet Center for Wildlife Damage Management Primarily nocturnal; get into bird feeders; not destructive or strong; 4 to 12 lb; hind print with opposable big toe