This is a list I scrabbled from this link on Iowa natives (NE) - click on the latin names in the link to see a photo (for most) as well as height, etc...
Not necessarily bird/butterfly plants, but many are
http://www.iowalivingroadway.com/plantListsResults.asp
Asclepias tuberosa butterfly milkweed
Campanula rotundifolia 4 - 20"
Corylus americana
Corylus cornuta
Crataegus pruinosa
Ceanothus americanus (not sure re birds)
Cornus canadensis
Dasiphora fruticosa ssp floribunda bush cinquefoil
Dodecathon amethystinum amethyst shooting star - I never heard of it, but...
Erigeron strigosis, daisy fleabane - maybe over low walls? Does it spread too much?
Filipendula rubra Queen of the prairie - too big?
Fragraria virginiana, wild strawberry
Heuchera richardsonii green flrs.
Impatiens capensis, spotted touchmenot pretty
Ilex verticillata - looks like a possibility
Monarda fistulosa, wild bergamot - pretty; does it reseed?
Penstemon grandiflora pretty, 2 - 4 feet
Penstemon palida, also pretty, 8-24"
Ribes americanum american black current
Sambucus canadensis elderberry
Teucrium canadense - I'd be interested in just how rangy it is, as I liked Teucrium chamaedrys (germander) in California as a nice dark ground cover - much tinier leaves, very controllable for me.
Tradescantia brachteada prairie spiderwort (does it run?)
Verbena stricta - very pretty