Use window boxes for birds if your gardening space is small. Jen says West Coast gardeners can grow Desert Zinnia (Zinnia acerosa, for Zones 6 to 9), Desert Sand-Verbena (Abronia villosa, for Zones 8 to 10), California poppy (shown here, Eschscholzia californica, for Zones 3 to 9) and Wild Canterbury Bells (Phacelia minor, for Zones 4 to 10) among others. They'll appeal to hummingbirds and finches.
East Coast window boxes with full sun and moist soil can hold Lowbush Blueberry (Vaccinium angustifolium, for Zones 2 to 8) and Butterfly Milkweed (Asclepias tuberosa, for Zones 3 to 9). Bluebirds, doves, robins and cardinals will feast on the berries while goldfinches and orioles like Butterfly Milkweed.
For a cold climate window box, Jen recommends decorating for the winter with cut stems of Winterberry (Ilex verticillata, for Zones 3 to 9). "The birds will eventually find your window box and snag the red berries." Pair them with stems of Eastern Red Cedar (Juniperus virginiana). Cedars provide nesting and roosting sites for juncos, various sparrows, robins and mockingbirds.