Regular loon cam watchers have witnessed various visitors to the nest, including painted turtles, snapping turtles, great blue herons, muskrats and eagles. Most of these visitors present little threat to nesting loons. In fact, loons can be quite tolerant of painted turtles, herons and muskrats, all of which are likely to use loon nest hummocks and the floating nesting rafts for perching (herons), sun basking (painted turtles) or feeding stations (muskrats). Snapping turtles can be a threat to chicks after they leave the nest but they are not a significant egg predator. Adult loons can easily defend a nest from a snapping turtle. Eagles, on the other hand, have been known to attack chicks, and adult loons in some cases, while on the nest. Most of our recorded eagle attacks in New Hampshire have occurred against chicks in the water after leaving the nest.
The leading cause of egg predation in New Hampshire is mammalian predation, with raccoons doing most of it. This is presumed to be the reason why loons prefer to nest on small islands or hummocks in marshes and use the mainland shore as a last resort. The more difficult it is for a terrestrial animal to access the nest, the safer the eggs. Other mammals known to pilfer loon eggs include coyotes, foxes, and some members of the weasel family (mainly mink). As development steadily increases on New Hampshire’s lakes, raccoons in particular become more prevalent because they have acclimated to human presence and view us and our waste stream as a food source. That plus the loss of good nesting habitat due to development has resulted in a higher probability of nest failure due to egg predation.