black duck en What To Look For When Observing Waterfowl <p>John Weeks describes the differences between a black duck and a mallard by describing their unique appearances. Weeks also brings up the topic of mites and the diverse ones that exist, including the green-winged teal.</p><p>&nbsp;</p><p>Originally aired on April 27th, 1984.</p> Tue, 24 Apr 2012 14:22:24 +0000 John Weeks 18105 at