Though human activities have allowed the expansion of a few species, such as the barn swallow and European starling, they have caused population decreases or extinction in many other species. Over a hundred bird species have gone extinct in historical times, although the most dramatic human-caused avian extinctions, eradicating an estimated 750–1800 species, occurred <answer>during the human colonisation of Melanesian, Polynesian, and Micronesian islands</answer>. Many bird populations are declining worldwide, with 1,227 species listed as threatened by BirdLife International and the IUCN in 2009.
When did the most dramatic human-caused avian extinctions occur?
during the human colonisation of Melanesian, Polynesian, and Micronesian islands