The mongoose was introduced to the Hawaiian Islands by the sugar plantation owners in the hopes they would control the rat population. Mongooses ('mongeese' sounds better to me, but ins't right...) are strictly diurnal, however, and rats are mostly active at night, so, as the Hawaiians put it, the two species never met. The mongooses are perfectly happy to eat the eggs of birds and sea turtles, and so they have decimated the endemic bird populations, and don't help the turtles much, either.