This is a Canada-Domestic Graylag hybrid that has lived at Stewart Park for several years. It was one of a brood of four raised by a pair of domestic geese, all clearly biologically unrelated to the male of the pair. The last of the parents disappeared in 2006. This one was the last remaining of the family.
Sadly, this bird has not been seen since early 2012 and is now assumed dead.
Canada-Domestic Hybrid, Stewart Park, 8/16/2007, Paul Anderson