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.
Some anglers use lead-weighted hooks, called jigs.
A sinker or jig may accidentally detach from a line and fall into the water, or the hook or line may become entangled and the line may break or be cut. A fish eating water bird, like a Loon, may be attracted to bait on a hook. It may swallow a sinker or jig attached to the line or to an escaped fish. Lead poisoning is not a small problem. Between 1.5 and 2.5 million migratory waterfowl die annually from consuming sinkers, jigs, or shot made from lead.