No backyard, no problem! If you have a balcony, piece of a roof garden, or simply a window with a box planter, you can provide food and water for wildlife. And be happy in the knowledge that you're meeting a real need.
The best vine for city-living may be Boston Ivy and wild birds love it's blue fruits. Nandina with its beautiful red fruits and lovely fall foliage can grow almost anywhere, including containers. Small hollies work well (be sure to have at least one male plant).
With windows and window boxes, offer hulled sunflower seed in a feeder such as one which can attach to glass with suction cups or to the wall. In warm weather, plant the window box with bright flowers to entice hummingbirds and butterflies. (See the accompanying article "Which Wildlife Needs What" for suggestions on what to grow.) You can also attach a hummingbird feeder to your window. Place a heavy shallow container in the center of your box for water.
If you can attach a nesting shelf to a wall, you may play host to robins, Eastern phoebes, or barn swallows. A nest box may entice the following neighbors: house sparrows, starlings, house wrens, titmice, chickadees, or even squirrels.