Bird Watching: DAILY PICS VOL. 24, 1 by Grasmussen

Grasmussen wrote:
There was a thin crust of ice on most of the water, at Potters Marsh today. This pair of Trumpeter Swans with one cygnet had kept a small area of water open, around where they were napping.

The other day Linthicum asked about predators on the cygnets. I have been puzzling over how to answer the question. I seldom see a pair with more then three cygnets. A normal clutch of eggs is 4 to 6. Obviously they are loosing cygnets to something, but I don't know what it is. Too cold for turtles here. Most of the nesting area is out of the areas occupied by Northern Pike, a large fish. (Pike do feed on ducklings.) Since the Trumpeter Swans are primarily aquatic, they are out of reach for most terrestrial predators. Wolverine are the only mammals which might be a predator, but they aren't very common. There are a few Jaegers in part of the nesting area, but not common. The only predator I can think of, would be Eagles.

Gary