Except for birds of open country, most birds rarely stray far from dense cover, because their lives depend upon quick evasion. Areas dense with weeds or brush are frequently occupied by birds, although you may not notice them at first because birds become still and silent as you approach. Brush piles are also favored, because the tangle of branches and trees prevents cats or hawks from gaining access.
Protective cover is also vital when birds are sleeping or waiting out bad weather. Conifers and other evergreens, as well as dense deciduous plants, shelter roosting birds from predators and wind, rain, and snow. Needle and broad-leaved evergreen trees and shrubs, such as white pines, arborvitae, spruce, junipers, cedars and hollies provide essential winter protection as well as food.
Different species of birds need different types of cover, however. Species like meadowlarks, field sparrows, and bobolinks prefer grassy meadow or prairie habitat for feeding and nesting.
To arrange your cover plants, determine the prevailing winter wind direction, and plant to provide protection from these winds. Winds from the northwest are common around the country, though the east coast may have its worst winter winds from the east. Rows of evergreens, or evergreens mixed with tall deciduous trees are effective for blocking wind, if planted with the wind direction in mind.
To create an effective barrier that is also rich in food and nest sites, mix in smaller trees and shrubs along the protected side. Add beds of perennials and annuals in front of that, for seeds and nectar. Look at the conditions that prevail in your yard and area to determine which habitat you want to emulate – whether it is wet and shade-loving, or sunny and dry.
Nature centers, botanical gardens and wild bird centers have information about plant communities that are native to your region.