Among the many examples of alien species of mammals that have caused damage is the indian mongoose. this animal was brought to hawaii in the 1800s to kill rats in sugarcane fields. since then, they have grow in numbers so that today they are a major threat to bird life on the islands. one of the mongoose's favorite food, in fact is birds' eggs. Thus,the mongoose has caused millions of dollars worth of damage to poultry farmers in hawaii, and it has greatly reduced the numbers of many native bird species. many of these species, which are unique to the islands, are now at now at risk of extinction.