Our year-round resident birds that eat bugs summer, spring, and fall must, by necessity, switch in winter. Most switch to berries. Robins, bluebirds, cedar waxwings, and mockingbirds, for instance, don't have bill structures to hull seeds, so they're dependent almost entirely on berries.
And they need an abundance of berries. A cedar waxwing eating dogwood fruits, for instance, needs 230 berries a day. While we humans can't eat dogwood berries, we do love blueberries. So by comparison, if we ate the same amount of blueberries relative to our weight of, say, 140 pounds, we would have to eat 46,577 berries--a whopping 215 pints--per day!
FMother Nature's grand plan, however, best feeds birds. While we humans usually choose low-fat, low-carb foods, birds in fall need just the opposite: high-fat, high-carb foods, a diet that meets their high-energy autumn needs. Curiously, about 70 percent of berries that birds love ripen in fall and contain high fat, helping them replace all those worn feathers, chunk-up for migration or ready themselves for winter.
By contrast, late spring/summer berries rank high in protein and carbs that promote growth, ripening to coincide with the end of nesting season when fledglings first seek food on their own. At the other extreme, winter berries have small amounts of fats; but as a result, they don’t spoil readily, thus lasting through the winter and even into very early spring in time for early returning migrants. It's a grand plan.
Still, even within a season, not all berries are created equal. Late summer and fall native berries contain higher fat levels than either non-native or invasive berries. In the Midwest, according to Cornell University, black raspberry and elderberry (fruiting July-early Aug.), and chokecherry and rough-leaf dogwood (fruiting Aug. -Sept.) all contain 30 to 50 percent fats, ranking them among the most nutritious berries.
By contrast, however, non-native invasive berry producers like multiflora rose, amur honeysuckle, or autumn olive contain no more than three or four percent fats. But here's the larger problem with non-natives: Because birds didn't evolve with non-native plants, they don't readily recognize them as food. Thus, birds often starve to death amid an abundance of non-native berries.
Finally, plants selected, consider where to place. Birds choose what and where they eat primarily for safety, choosing safety over quality. So plant in clusters, near other vegetation, creating natural protection against predators.
In short, the goal for expanding your bird-viewing pleasure is three-part: Plant berry producers. Plant natives. And plant them where feeding birds feel safe.