Goose, polluters of Nevada lake
A new breed of polluter is causing havoc in Lake Tahoe, a freshwater lake in Sierra Nevada, on the border between the us states of California and Nevada.
The lake's bed has a two-inch coat of Canadian geese droppings. The bird takes refuge in the lake when they moult their primary wing feathers in spring. A 4.5 kg-Canadian goose can produce around 2 kg of nitrate and phosphate-rich droppings every day. A sewage spill at the lake "is nothing compared to what is being done by these geese', says wildlife biologist Jack Spencer.