Feral housecats are a significant threat to native bird species. They are present from shoreline to treeline. They've been documented and even filmed killing native birds in their nests, and are regularly trapped in nene nesting areas. Toxoplasmosis from feral cats was a major mortality factor in the failed reintroduction of captive-raised hawaiian crows, and threatens other native bird and mammal species. Fluffy may be cute, but also very deadly.