Zoo collection management is increasingly driven by meeting global conservation needs. Many avian species have experienced population declines throughout Southeast Asia, underscoring the importance of ex situ conservation in these countries. We focus on Thailand, a bird diversity hotspot with a long tradition of keeping birds in captive settings. We aimed to understand what drives species acquisition and maintenance in Thai zoos. To that end, we surveyed 55 zoos, making a complete inventory of reptiles, birds, and mammals on display. We recorded 249 bird species, of which 149 are not native to Thailand. Bird species diversity was positively correlated with mammal species diversity but not with the entry ticket price, the Gross Domestic Product of the province in which the zoo was based, or the size of the zoo. Diversity did differ significantly between zoo types (accredited, government and private zoos). There was a clear difference in the proportion of native and non-native species between zoos, with private zoos containing the highest number of non-native species, which may be related to the licensing status of these zoos. The composition of bird species in Thai zoos appears to be largely driven by their availability, the legal status for keeping them and serendipity. The conservation status seems to be of minor importance, contradicting the typical role of a zoo. To be considered global conservation players, zoos in countries of high species diversity, such as Thailand, have the unique opportunity to provide breeding programmes for some of the rarest species, yet they must improve their collection management plans to focus on such aims.