While the fruits of plants, including large trees, small trees, and shrubs, provide birds with nutrition throughout the year, these sources are essential as wild food for winter birds. Food becomes scarce in the absence of warm-weather insects, a major source of nutrition. Many birds migrate south to be near a reliable supply of insects, but for those that overwinter in the northern hemisphere, fruits (seeds, nuts and nutlets, cones, and berries) are often plentiful.
The Relationship Between Birds and Food
There is an especially useful ecological relationship between birds and plants that bear fruit. Trees and shrubs produce fruit and berries to help disperse their seeds. They utilize birds, who are attracted to fruit that tastes good and who eat and spread the seeds. The seeds have a tough seed coat, which helps them remain viable while moving through the digestive system. When the fruit and seeds pass through the birds’ digestive tract, they are fertilized and scarified, and then dropped away from the parent plant, ready to germinate in spring. Some fruiting shrubs and tree species may even require their seeds to go through the digestive tract of a bird to complete the reproductive cycle.
All flowering seed plants produce fruit, but with varying calorie and nutrition levels. The more calories a food has, usually the more sought after it is. Competition for food is high among birds, and desirable fruits are eaten to depletion earlier in the season, leaving less calorie dense food as the only obtainable option. Birds will not hesitate to eat this less nutritious food when they need it.
Food for Wisconsin’s Overwintering Birds
These foods grow at various times of the year, and many plants hold onto their fruit through the winter months. These fruits and berries are important to many species of Wisconsin’s overwintering birds. American Robins and Eastern Bluebirds form flocks of mixed species that move to where food is throughout the season. The Black-capped Chickadee, Northern Cardinal, Song Sparrow, and Downy Woodpecker are dependent on Wisconsin’s winter fruits. Goldfinches eat the seeds of coneflowers, which is why it is good to leave them standing after the growing season. The Cedar Waxwing, whose diet is mostly fruits through all seasons, is known to feast on berries throughout winter. Interestingly, it even eats berries that have fermented, causing the bird to become intoxicated!
Planting Trees and Shrubs
Birds in the wild rely on these fruits; planting them will attract birds to your yard while helping to feed them. It takes planning to choose the best species for your yard’s conditions. If you wish to help birds in winter, think about planting a diverse group of tree and shrub species, as they will bear fruit at various times and will provide a spectrum of calorie counts. There will always be a supply that is ready to eat, bringing more birds to your yard throughout the winter.
In addition to diversity, there are other considerations. Choose native plants, which are species that existed naturally in an area before European settlement. These plants are adapted to the local climate, soils, and precipitation. They co-evolved with local species, providing food that possesses the right size, availability, and calorie levels. Natives also provide shelter from the elements.
Other characteristics you might consider include the plant’s soil preferences, light preferences, showiness, hardiness, size, and size of its fruit, which should be small enough to feed birds. Visit a botanical garden or arboretum to see what the mature plant will look like. Consider the following suggestions and visit your local nursery for the best individualized advice.
Among large trees, three excellent choices for homeowners are oak, hackberry, and evergreens, such as juniper. Oak trees (Quercus) attract the attention of many birds because their nuts are very nutritious. Choose the species that are native to Wisconsin, all of which provide acorns. Birds that eat acorns include Northern Flicker, Red-headed Woodpecker, Blue Jay, and others.
Hackberry (Celtis occidentalis), a deciduous tree with light colored wood, produces small nutlets that turn orange red to dark purple in autumn that are eaten by as many as 24 bird species through the winter. It is especially liked by Northern Flicker, Northern Mockingbird, Swainson’s Thrush, and Northern Cardinal. It’s a great street tree, so if your municipality offers to plant one in your yard’s parkway, take it.
Junipers (Juniperus) are hardy evergreens that produce seed-bearing cones on female plants. They come in a variety of different heights and are extremely hardy. Juniperus virginiana grows primarily in southern Wisconsin, and 54 species are known to eat its fruit, including Cedar Waxwing, Northern Mockingbird, Brown Thrasher, and Gray Catbird.
Numerous species of serviceberry (Amelanchier) grow as small trees or large shrubs. Their summer fruit, a red to purple berry-like pome which is nearly black at maturity in June, is attractive to fruit-eating birds like American Robins and Cedar Waxwings.
Another small tree that birds like is the crabapple (Malus). The crabapple is smaller than other apples but is otherwise the same fruit. The persistent, bright red crabapple fruit will stay on the trees until birds locate it in late fall and winter and is especially liked by American Robins.
Viburnums (Viburnum) include highbush cranberry, nannyberry, and several other native species. They produce drupes, which provide nutrition with plums, cherries, and other wild fruits. Nannyberry (V. lentago) fruits in fall, and the winter’s light red buds and can feed Gray Catbird, American Robin, Eastern Bluebird, and Cedar Waxwing, producing a sought-after food with high nutrition and calorie counts. Highbush cranberry (V. trilobum) is a late fruit often remaining on the plant through most of the winter as well. These fruits are bitter and are eaten after being frozen, when they are more desirable and often when nothing else is available.
Chokeberry (Aronia) is a deciduous shrub. It is often used as a backup option when food becomes scarce. The small, dark purple fruits on these plants are very astringent and offer fewer calories, protein, and other nutrients. They are still extremely useful to birds.
Rose (Rosa) is a beautiful shrub whose fruit is variable, with some species producing large showy hips favored by many birds. Single flowers attract more pollinators than the many petaled double hybrids, producing more fruit. One example is the prairie wild rose (R. arkansana), whose rose hips feed more than 38 species in late fall and early winter, including Northern Cardinal and Brown Thrasher. Rose is one of the most common yard plants and will produce its often-ornamental rosehips if growers don’t deadhead the plants. Plant single-flower shrub roses, such as Frau Dagmar Hartopp Rose, instead of multi-flora rose, as the latter are invasive in Wisconsin.
Winter Fruit for Birds at the Center
The Center’s conservation team creates management plans with bird conservation in mind, and it includes planting and maintaining shrubs and trees that possess fruits that birds desire. In the West Meadows, where invasive woody plants are removed using brush mowing, the team has mapped areas of native shrubs. Beginning in 2017, the team created conservation areas that leave these shrubs intact, including nannyberries and dogwoods, which are then utilized by birds for food.
In our Hardwood Swamp, the team plants various species including hackberry, oaks, Aronia, winterberry, and cherry species. Several berry plants that help birds are grown at the Center, such as gooseberries, blackberries, and currants. The currants have no thorns and are a great species to plant in your yard.
Visit the West Meadows, Hardwood Swamp, and areas within the North Ravine restoration area to see our native fruiting plants in winter. If you have native plants in your yard, a beneficial practice is to leave them standing when they are through growing for the season. These remnants will provide a place to perch and offer seeds to winter birds, allowing you to experience the thrill of seeing numerous bird species visit your yard throughout the season.
Written with contributions from Michelle Allison, Sandy Manning, and Drew Shuster.