The most current dates are probably those in Bruce Peterjohn's "Birds of Ohio'.  When I first started birding I used the papers done by Donald J. Borror (1950) and Milton Trautman (1968.  They are a both a little outdated and are for Central Ohio, but they give you the basic idea.  Just remember that Southern Ohio will be a week or so ahead of these dates and Northern Ohio a week or so behind. 
 
Milton Trautman's paper:
http://tinyurl.com/62o4ouq 
 
Donald J Borror's paper:
http://tinyurl.com/6lyqw9l 
 
A good thing to carry along is the Ohio annotated checklist.  The bar graphs show when the bird should be here and it's relative abundance.  If you are a new birder and see something new check the birds timing and abundance.  If it's March and it shows the bird as being here in May or is accidental for that March, double-check your sighting.  It is a good way to learn distribution and timing.  It also saves the embarassment of reporting nighthawks in February.  Here  is a link to an older version http://www.ohiobirds.org/publications/OBRClist.pdf  .  If you want to get the newest version check the Ohio Ornithological website at: 
 
http://www.ohiobirds.org/publications/checklist/checklists.php
 
 
 
John Pogacnik                                     
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