Water level fluctuation with resultant flooding of nests, or stranding the nesting adults too far from rapid escape to the water. Entrapment and drowning in fishing nets on the Great Lakes and oceans. Accidentally landing on wet roads and parking lots, which appear as open water. The heavy bird is easily injured by its own weight, and may become infected and die. Becoming ice bound by early winter ice.
Birds can quickly become hypothermic and perish.
Competition from exotic and aggressive Mute Swans, and exploding cormorant populations that compete for fish Botulism infections may occur in periodic epidemics with hundreds of loons dying on the Great Lakes. Decrease in fish supply or other food due to over fishing or contamination of water. A visual predator, the loon needs clear, clean water to catch its prey. Let s Get the Lead Out Every year, loons, swans, cranes, and other water birds die needlessly from lead poisoning after swallowing lead fishing sinkers and jigs. Sport anglers attach lead weights to fishing lines to sink hook, bait, or lures into the water.