Figure 2: The global distribution of those records in GAVIA that contain sufficient information to have been converted into distribution maps (dark grey).
From: The global avian invasions atlas, a database of alien bird distributions worldwide

These include all status categories, so introductions that have both succeeded and failed. Light grey areas are mainly those for which there are no records of introduction (or in a few cases, records that could not be mapped), although whether it is actually the case that no alien birds have been introduced to these places (versus a lack of records) is unknown.