A Common Loon was observed on the nest until May 26th. On that day, the pair of adults were observed nearby with no juvenile(s). They left the bay in the evening and did not return for several days. On June 4th, I checked the nest more closely and found some egg remains. It would appear that predation had taken place, possbily by Raccoon, which caused the adults to abandon the nest.
(Photographed June 4, 2016 on lower Chemong Lake, Emily Township, City of Kawartha Lakes, Ontario, Canada)