Chipmunks are omnivores with a strong lean toward seeds and nuts. The core diet is acorns, beechnuts, hickory nuts, and the seeds of grasses, wildflowers, and trees, rounded out with berries and other fruit, mushrooms and other fungi, fresh greens, insects, earthworms, snails — and, opportunistically, bird eggs and even small vertebrates. What sets chipmunks apart is not what they eat but what they do with it: stretchy cheek pouches let one chipmunk carry a half-dozen acorns at a time to an underground larder that may hold thousands of seeds, the pantry it dozes over all winter.
North America hosts nearly all of the world’s roughly 25 chipmunk species — the familiar eastern chipmunk (Tamias striatus) across the East, a whole radiation of smaller species in the West, with only Asia’s Siberian chipmunk elsewhere. All are small, striped members of the squirrel family (an identity we unpack across our squirrel hub), and all share the same food-driven lifestyle: gather relentlessly, hoard underground, survive winter on the pile. Here is the full chipmunk menu, season by season, plus what it means for your feeders, bulbs, and garden.
The Core Diet: Seeds, Nuts, and Mast
If it is a seed, a chipmunk wants it. Hard mast — acorns, beechnuts, hickory nuts, hazelnuts — forms the storable backbone of the diet, and a chipmunk’s autumn revolves around the oak and beech crop; in big mast years chipmunk populations visibly boom the following summer. Around those staples flow the seasonal seeds of maples, conifers, grasses, and wildflowers, plus cultivated windfalls: sunflower seed under feeders, cracked corn, oats, and spilled pet food. Soft matter fills the gaps — strawberries, raspberries, blackberries, cherries, apples, and wild fruits in summer, and a steady side of mushrooms and other fungi, including underground truffle-like species the chipmunk digs and, in dispersing their spores, quietly plants for the forest’s benefit.
The Carnivorous Side of a Cute Animal
The chipmunk’s omnivory surprises people. Alongside the seeds, chipmunks routinely eat insects (beetles, caterpillars, grasshoppers), earthworms, snails, and slugs, and they are documented opportunistic predators of bird eggs and nestlings, frogs, small snakes, baby mice — even, rarely, a smaller chipmunk. Ground-nesting songbirds in chipmunk-dense woods lose a meaningful share of nests to them in some studies. None of this makes the chipmunk a menace; it makes it a typical small omnivore, taking cheap protein where it appears, especially in spring and while raising young when protein demand peaks. If a nest box in your yard was raided, the striped culprit is at least as likely as the neighborhood jay.
Cheek Pouches and the Underground Pantry
A chipmunk’s defining equipment is its cheek pouches — elastic pockets opening inside the lips that expand back toward the shoulders. A loaded eastern chipmunk can carry a remarkable haul per trip (classic naturalist accounts count over 30 beech seeds, or three to six acorns, per load), which transforms foraging economics: instead of eating where food falls, exposed to hawks and cats, the chipmunk shuttles food to safety in dozens of quick, low-risk trips. The destination is a larder chamber in its burrow — a tunnel system commonly 10 to 30 feet long with a nest chamber, food storage, and discreet, dirt-free entrances. A single chipmunk’s cache can run to several thousand seeds and nuts in a good fall. Unlike tree squirrels, which scatter-hoard nuts across the landscape one burial at a time, most chipmunks bet everything on a few defended larders — the two strategies are a classic contrast we explore in tree squirrels vs ground squirrels.
A Day in the Feeding Life
Chipmunk foraging runs on a strict risk budget. The day starts after sunrise and ends before dusk — chipmunks are firmly diurnal, with activity peaking mid-morning and mid-afternoon — and nearly all of it happens within a small home range centered on the burrow, typically half an acre or less in good habitat. Rather than grazing in the open, a chipmunk works in sprints: dash to the seed source, stuff the pouches at top speed, dash back to cover or the burrow, repeat. Researchers watching provisioned chipmunks have counted dozens of round trips in a day when a rich food source (a heavy-mast oak, or your feeder) is on the route. The vigilance is warranted — hawks, foxes, weasels, snakes, and house cats all take chipmunks — and it explains the sound track of a chipmunk woods: the sharp ‘chip’ alarm for ground predators and a lower ‘chuck’ many populations use for raptors, each sending every chipmunk in earshot to its hole.
The burrow itself is a marvel of discreet engineering: a main entrance barely 2 inches across, no soil pile (the chipmunk hauls excavated dirt away in its pouches and scatters it), tunnels running 10 to 30 feet to a leaf-lined nest chamber, food galleries, and one or more hidden spare exits. Everything about the design serves the same food-security logic as the cheek pouches: get the goods underground, quickly, without advertising the address.
Eastern vs Western Chipmunks: Same Strategy, Different Menus
The eastern chipmunk of deciduous woods is the mast specialist — its year genuinely orbits the acorn and beechnut crop. The many western species (least chipmunk, yellow-pine chipmunk, Townsend’s chipmunk, and some twenty more) apply the identical pouch-and-larder strategy to different pantries: conifer seeds pried from pine and fir cones, the seeds of sagebrush, manzanita, and mountain shrubs, grass seeds, berries, and a heavy load of fungi in the wetter forests of the Northwest. The least chipmunk — the continent’s smallest, at well under 2 ounces — forages from sagebrush flats to alpine meadows, while Townsend’s chipmunk works the dark, mushroom-rich understory of Pacific rainforests. Wherever you meet one, the behavioral fingerprint is the same: stripes, sprints, bulging cheeks, and a burrow full of savings.
Winter: Not Quite Hibernation, More Like Snooze-and-Snack
Chipmunks handle winter with a strategy all their own. They are not true, months-long hibernators living off fat like groundhogs, nor active winter foragers like gray squirrels (whose approach we cover in what squirrels do in the winter). Instead, a chipmunk retreats underground around the first hard frosts and enters bouts of torpor — body temperature and heart rate plunging for days at a time — punctuated by regular wake-ups to eat from the larder beside its nest, and even to surface on mild midwinter days. The whole system runs on the fall cache rather than body fat, which is why autumn hoarding is so frantic: a chipmunk that stores too little does not wake up in spring. Emergence comes in late winter, when you may see chipmunks tunneling up through snow to raid feeders weeks before the ground thaws.
| Season | Mainstays | What you’ll notice |
|---|---|---|
| Spring | Emerging greens, buds, leftover cache, insects, eggs | Feeder raids; digging in beds; occasional nest predation |
| Summer | Berries and fruit, seeds, fungi, insects and worms | Strawberry and tomato sampling; burrow traffic |
| Fall | Acorns, beechnuts, hickory nuts, sunflower seed — in bulk | Nonstop cheek-pouch shuttling; bulb digging |
| Winter | The stored larder, eaten between bouts of torpor | Near-total disappearance; brief mild-day surfacings |
Chipmunks in the Garden: What They Target
Chipmunk garden damage is real but usually smaller than it looks — and smaller than the rap sheet of the deer and rabbits working the same beds. The classic complaints: freshly planted flower bulbs dug and eaten (tulips and crocus especially; daffodils and alliums are generally left alone), strawberries and low tomatoes nibbled, seedlings clipped or excavated, seed trays raided, and holes probed in mulch and containers. Under bird feeders they are less pest than cleanup crew, though a feeder can subsidize an unnaturally dense chipmunk population — several burrows per yard where seed rains down daily. If the digging escalates from foraging to real trouble, or you cannot tell chipmunk work from the mounded excavations of larger burrowers, our guides to groundhog feeding habits and their telltale sign help sort the suspects: chipmunk entrances are tidy 2-inch holes with no soil apron, nothing like a groundhog’s soil-fanned portal.
What Baby Chipmunks Eat
Chipmunk pups — usually three to five per litter, born blind and hairless in the burrow’s nest chamber in spring (and, in much of the East, a second litter in late summer) — nurse for their first month and change. They emerge above ground at five to seven weeks looking like slightly scruffy miniatures of their parents, sample solid food immediately, and are weaned and foraging for themselves within a couple of weeks of emergence. Independence comes brutally fast: by eight to ten weeks the young disperse to dig their own burrows, and a first-fall juvenile faces the same math as any adult — cache enough before frost or don’t see spring. That urgency is why late summer yards suddenly seem overrun with small, reckless chipmunks; they are that year’s graduates, learning the risk budget on the job.
One more note for feeder-watchers: a chipmunk under a bird feeder is not really eating — it is exporting. Where a gray squirrel sits and dines, a chipmunk pouches seed at a rate of a visit every few minutes and banks it underground, so the same spilled cup of sunflower seed feeds a squirrel once but stocks a chipmunk’s winter larder for a week. That difference is worth remembering in fall, when nonstop shuttling can read as an infestation; it is usually one or two animals working a deadline, and it stops the day the frost sends them below.
Do chipmunks eat bird eggs?
Yes, opportunistically. Chipmunks take eggs and nestlings from ground and low shrub nests when they find them, and research on ground-nesting songbirds identifies chipmunks among the significant nest predators in eastern forests. It is normal omnivore behavior rather than a specialty — eggs are an occasional protein windfall, not a staple.
What do chipmunks drink?
Mostly water — from dew, puddles, birdbath edges, and streams — supplemented by the moisture in fruit and greens. A chipmunk’s seed-heavy larder diet is dry, so reliable water matters, and a low, safe water source (a ground-level dish with an escape stone) is one of the more genuinely helpful things a wildlife-friendly yard can offer.
Is it OK to feed chipmunks?
Occasional unsalted nuts or seeds won’t harm the chipmunk, but deliberate feeding is a mixed bag: it concentrates burrowing near foundations, subsidizes densities that natural food can’t support, and habituates a wild animal to approach people and pets. Skip salted, flavored, and processed foods entirely. If you enjoy chipmunks, a brushy corner, a water dish, and native seed-bearing plants beat a feeding station.
Do chipmunks eat mice or other animals?
Small vertebrates do appear on the menu — documented items include frogs, small snakes, nestling birds, and infant mice. These are opportunistic grabs, not hunting in any organized sense; a chipmunk is itself prey for hawks, foxes, weasels, and house cats, and it forages accordingly, in quick dashes between cover.
