Ecological and socio-economic factors affecting extinction risk in parrots

Parrots (Psittaciformes) are among the most threatened bird orders with 28 % (111 of 398) of extant species classified as threatened under IUCN criteria. We confirmed that parrots have a lower Red List Index (higher aggregate extinction risk) than other comparable bird groups, and modeled the factors associated with extinction risk. Our analyses included intrinsic biological, life history and ecological attributes, external anthropogenic threats, and socio-economic variables associated with the countries where the parrot species occur, while we controlled for phylogenetic dependence among species. We found that the likelihood of parrot species being classified as threatened was less for species with larger historical distribution size, but was greater for species with high forest dependency, large body size, long generation time, and greater proportion of the human population living in urban areas in the countries encompassing the parrots' home ranges. The severity of extinction risk (from vulnerable to critically endangered) was positively related to the per capita gross domestic product (GDP) of the countries of occurrence, endemism to a single country, and lower for species used as pets. A disproportionate number of 16 extinct parrot species were endemic to islands and single countries, and were large bodied, habitat specialists. Agriculture, hunting, trapping, and logging are the most frequent threats to parrots worldwide, with variation in importance among regions. We use multiple methods to rank countries with disproportionately high numbers of threatened parrot species. Our results promote understanding of global and regional factors associated with endangerment in this highly threatened taxonomic group, and will enhance the prioritization of conservation actions.