Interesting presentation last night at Petoskey Audubon by Vern Stephens of MDNR discussing the restoration of Michigan's grassland ecosystems and specifically the work at Arcadia Dunes near Frankfurt.  Grasslands are immensely diverse and beautiful ecosystems.   Prior to European settlement Michigan had approximately 2 million acres of grassland and now, according to the Michigan Natural Features Inventory, less than 1% of the original prairies remain. 
Apparently, restoration is worth considering for parcels as small as half an acre.
http://www.gtrlc.org/land-stewardship-project/grassland-restoration/
If you don't go that far, there's much that can be done with garden plants to attract wildlife to the yard and this book is recommended:
http://www.amazon.com/Bringing-Nature-Home-Wildlife-Expanded/dp/0881929921/ref=sr_1_2?s=books&ie=UTF8&qid=1334160126&sr=1-2