It is true that you simply do not get the density of wildlife in a shade garden. With less sunshine, there is less food production and that affects all the animals up the food chain. However, beautiful and floriferous shade gardens are easily achieved and you can still attract a decent amount of wildlife. I would also say that if aesthetics are important to you, then you should place greater emphasis on leaf textures in shade gardens because the leaves in shady areas do not get burnt by the sun and look better.
With less emphasis of flowering perennials in a shade garden, more thought can be given to a diversity of plants that includes small trees, shrubs, ferns and sedges. Most grasses cannot handle shade, so take a look at sedges instead as these plants often have excellent value for wildlife.
The seasons to focus on in a shady garden are spring and fall. In the spring, you have shrubs that flower as well as woodland flowers. In the fall there are the asters and goldenrods that can add some flower power.
Here is list of plants that can be grown for wildlife in the shade or in part-shade.