Added 14 May 2016.  Birdtrax appears obsolete.  County lists are available from ebird under ABA alerts via email for counties or regions.  Recent lists below use ebird.  

"Birdtrax Slater" in a browser provides fast access to this page or you can bookmark counties in Google sites.  As of 1 Jan 2015, Birdtrax only provide one useful tab - rarities.  Checklist for counties or regions are available via the ebird site.  These are useful to review what others have seen and who has been out birding.

Washington State (rarities takes awhile)  Washington State (recent checklists) 

Washington State (counties counts, counties are selectable)

King Co., WA (recent checklists via ebird)

Pierce Co., WA (recent checklists via ebird)

Ebird NW