This data is taken from eBird, a Citizen Science project to collect birders’ checklist data from around the world for use by researchers and scientists.  Data in this chart was accessed on 3/18/2014 from ebird.org.  The data is for all of the month of May [only] and is for all years (1900-2013).  The cheat sheet is for Northwest Ohio including the counties of Erie, Ottawa, and Lucas.  Even though this chart covers the whole month of May, it can still be used as a guideline for Biggest Week this year which occurs from May 6-15, 2014.  Check out the main festival site here: http://www.biggestweekinamericanbirding.com/.

The first column is taxonomical sequence.  The second column is a difficulty rank based on the highest number of individual birds per checklist for a specific species for May in the Biggest Week area.  The lower the difficulty number, the easier the bird is to see (more birds per checklist).  Likewise, the higher the difficulty number, the harder that species is to see.  The third column is the week in May in which that species peaks–reaches its maximum value for birds per checklist. Column 4 is the species common name.  Column 5 is the actual maximum value of birds per checklist that a species achieves in May in the 3-county area.  Column 6 is like column 3 but is specific to actual day (as opposed to week of the month).  The last column is the average number of checklists submitted during May in the 3-county area to see 1 (one) individual bird.  This is calculated by taking the reciprocal of the peak value of abundance (birds per checklist).  For example, Ovenbird reaches a peak of 0.480 birds per checklist.  So 1 divided by 0.480 equals 2.0833 [checklists to see 1 bird].  But since a fraction remains I add 1 to it to get to 3 checklists to see 1 bird.  Got it?  Good.