About 3 years ago i saw a pair of whooping cranes at milwaukee zoo but in a caged in aviary. The national zoo in D.C. seems to have a pair,but this exhibit seems to be the best.
San Antonio Zoo, Calgary Zoo, Smithsonian's National Zoo, Lowry Park Zoo (still have theirs?), Milwaukee Zoo and Zoo New England - Stone Zoo. International Crane Foundation also houses them as does Audubon's ACRES facility. There could be others but I am unsure of non-Zoo related facilities.
there's a nice article here from 2010 which runs through the history of whooping cranes in captivity (and includes European collections which held them, and their holding dates; both are slightly at odds with what is on Zootierliste, if there are any editors reading this...).
San Antonio Zoo, Calgary Zoo, Smithsonian's National Zoo, Lowry Park Zoo (still have theirs?), Milwaukee Zoo and Zoo New England - Stone Zoo. International Crane Foundation also houses them as does Audubon's ACRES facility. There could be others but I am unsure of non-Zoo related facilities.
I believe Jacksonville Zoo still have them as well - I saw them there (and at Lowry Park) in late 2013. Lovely birds - and even more so for me as they were the last 'new' crane species I had left to see.