Wild-bird trade and exotic invasions: a new link of conservation concern?

Exotic invasions are viewed as a major threat to global biodiversity, but predicting potential invaders is still a difficult task. Here, we highlight a hitherto unnoticed link between the increasing demand for pet birds in developed countries and avian invasions. Paradoxically, it is not the most common caged bird species that seem to be the most successful invaders, but those that are caught in the wild and traded on the pet market. Captive-bred species appear to have lost their ability to return to nature. Thus, the risk of biological invasion in importing countries should inform the current debate over potential bans on the wild-bird trade worldwide. This is a new piece of an already complex puzzle, in which the social, economic, and environmental aspects of both the importing and exporting countries must be weighed before any policy or resource-management measure can be instituted.