I hope this ends the questions.  The easy answer: it depends where you 
are.  The population status of migratory birds varies every year, and it 
is determined separately by species and location; it depends on the 
species breeding success for the year and its migratory flight patterns.  
For waterfowl in the continental US there are 4 Flyways, and you are in 
the Atlantic here (MD).  The info you asked for was easy to find (if you 
looked), but for a simple one page summary go to: 
http://www.dnr.state.md.us/dnrnews/pressrelease2005/082605.html ;

Note:  The seasons and bag limits are determined each year, and every year 
may be different.  This process is coordinated between the USFWS and each 
state.  Therefore, you'll have to check again next year to know which 
species can be hunted then; when; and what the state limits are for each 
species.

For the federal "big picture" info, you can read about this subject at 
http://www.fws.gov/migratorybirds/mgmt/mgmttbl.html.  FYI from the USFWS 
website:  There are over 860 species of migratory birds in North America. 
Only 58 of these have been designated as game species for which hunting 
seasons can be established.  The rest, over 800 species, have no sport 
hunting seasons and are protected by the Migratory Bird Treaty Act. 

Jeff Shenot
Croom MD