Species Profile - Cackling Goose
Following its split from Canada Goose a number of years ago, identification of Cackling Goose from Canada has become a necessary skill. To take it a step further, identification to subspecies is of interest to some. Although some references have indicated that only Richardson's Cackling Goose (subspecies hutchinsii) occurs in the east, the two birds seen together in Flushing Meadows Park in Queens, NY in the winter of 2015-16 suggest otherwise. Of the other three subspecies, Taverner's (tavernii) would be the most sensible.    
The two feeding together near the "Pool of Industry" at Flushing Meadows - Corona Park, 16 January 2016.   The smaller Cackling Goose in a relaxed posture, the larger one alert, exaggerating the size difference.
The smaller one. If you were scanning the Flushing Meadows flocks, the distinctly smaller size of this one made it the one to look for. The larger one would always be nearby. Various postures shown on the right illustrate how neck length and head profile can change appearance. A beige tint on the cheek patch is an interesting addition to its set of characteristics that are highlighted by the stunning white neck collar.

The larger one. Top pictures to the right illustrate the change in appearance going from relaxed to alert posture. At a distance (lower far right), not looking a whole lot different than the canadensis subspecies of Canada Goose. On closer inspection, head and bill shape differ. The presence of a gural stripe should be unique in the Flushing Meadows flocks, but maybe it's time to start looking more closely at Canadas. The unexpected eye ring on this individual give this bird a large beady eyed look than may help in picking it out.