The Clear Creek Trail in Coralville provides an excellent resource for biking, running, walking, and (most importantly!) birding. There is a very well-maintained paved trail that runs both east/southeast and west from the 12th Avenue access point; in addition, there are a variety of dirt bike trails that are relatively accessible. (Furthermore, with long pants and sturdy shoes, there are many wooded areas that are easily accessible in the absence of trails.)
Over the past three years, I have almost exclusively birded the west branch of the trail, between 12th Avenue and 22nd Avenue/Camp Cardinal Road. I'm sure that there are excellent birding opportunities on the east/south branch of the trail; I simply never get there, as I can easily spend many hours tromping around on the west branch alone. (Also, the section of trail west of 22nd Avenue is relatively new; I have not birded that portion of the trail, either.)
If you're looking for shorebirds, this is not going to be your cup of tea, but Clear Creek is a very good place for songbirds, particularly when you get a little bit off the beaten path. (The Trail is also home to a variety of mammals, including White-tailed Deer, Red Fox, Groundhog, and (I think) Muskrat.)
The following map is annotated with rough locations of a few species of interest, but there are good birds to be found almost everywhere along the trail.
Brown Creeper photos from 2004
Other birds from 2004