A Graylag Goose, which has been seem for at least a week on the Reservoir was on The Lake of Central Park today. The spotted black/yellow bill coloration and white feathers around the bill, suggest that it is most likely a Graylag Goose x Swan Goose Hybrid. The bird is most likely an escapee from a poultry farm.
We used to have a number of Domestic Duck/Mallard hybrids on The Pond and The Meer and we had the Mandarin Duck last winter. So, another hybrid is just par for the course I guess.