This appears to be a Canada goose watching his reflection in the water at the Roslyn Pond. It resembles a Cackling goose whose bill is more triangular in shape.
They are pretty common in North America and tend to be quite long-lived. There are seven subspecies of Canada geese and this one is probably the Atlantic version.
Canada geese (Branta canadensis) feed on grasses, grains and berries. This male is quite large as geese go (the Giant Canada goose can weigh up to 20 pounds).
Also in the same pond were lots of Mallard ducks. The Mallard (Anas platyrhynchos) is probably the most well known duck and these four males are typical of the green head and the chestnut-brown body.
In the foreground is a female Mallard identified by its mottled brown color and orange-splotched bill.