What do deer eat?

The facts in one table

Sources: Penn State Extension · USDA Forest Service

Browser, not grazer — and why that matters

A grazer crops grass at ground level; a browser works at waist and shoulder height, selecting the growing tips of shrubs and young trees. Deer are browsers, and that single fact explains almost everything gardeners and foresters complain about. The damage shows up on the parts of a plant that drive its growth, in a band from the ground up to about the height of the animal's head.

It also explains why deer are selective rather than indiscriminate. Penn State Extension describes preferred foods being eaten first, marginal foods only when the preferred ones become scarce, and starvation foods only when nothing else is left. Which species end up in which category is local: in Pennsylvania, work compiled by the Bureau of Forestry and others identifies blackgum, oak, basswood, maple, tulip poplar, aspen, hickory, ash and pin cherry as preferred browse.

Sources: Penn State Extension · USDA Forest Service

Autumn is about acorns

Penn State Extension notes that from late summer to early winter fruits and nuts make up a large part of a deer's diet, and that acorns form a significant portion of the autumn diet when available. The qualifier matters: oak mast crops swing enormously from year to year, so the autumn diet in a heavy acorn year looks nothing like the autumn diet after a failure. Deer movement, body condition and the pressure they put on other plants all follow that cycle.

Source: Penn State Extension

Deer in a garden

Because deer are selective browsers, a garden reads to them as a concentration of preferred food at exactly the right height. The honest conclusion from the extension literature is that food choice shifts with availability, so "deer-resistant" plant lists describe a preference, not a rule — the same plant can be ignored in a good mast year and stripped in a bad one. Fencing is the only approach that does not depend on the animal's mood.

The same logic applies to woodland. Where deer numbers are high, browsing removes the seedlings and saplings of exactly the preferred species listed by the Bureau of Forestry, so the next generation of forest is quietly edited by diet. That is why extension services talk about enhancing browse across an area rather than feeding animals in one spot.

Sources: Penn State Extension · USDA Forest Service

What most people get wrong

• "Deer eat grass." They are browsers: forbs and woody browse, plus soft and hard mast, are the important forages.
• "Deer-resistant plants are safe." Penn State describes preferred, marginal and starvation foods — when preferred food runs out, the list changes.
• "Feeding deer helps them through winter." Supplementary feeding concentrates animals and does not fix a diet built on dispersed browse; extension services recommend improving browse instead.

Sources: Penn State Extension · USDA Forest Service

Frequently asked questions

Do deer eat acorns?

Yes — Penn State Extension says acorns form a significant portion of the autumn diet when available, and that fruits and nuts are a large part of the diet from late summer to early winter.

What is "browse"?

The buds, stems, leaves and bark of woody plants. Deer are classified as browsers because browse and forbs, not grass, make up most of the diet.

Are deer selective about what they eat?

Very. Preferred foods go first, marginal foods are eaten when the preferred ones become scarce, and starvation foods only when nothing else is available.