The ecological impacts of invasive alien species (IAS) are increasingly documented, however, they are usually studied through the lens of either the IAS or the species that suffer from them (IAS-threatened species). A clear understanding of how both protagonists of biological invasions are characterized is still lacking. We investigated the morphology, life-history, and ecology of birds involved in biological invasions. Evaluating the disposal of 450 IAS-threatened birds and 400 alien birds in a functional space, we found that both groups harbored various strategies. Aliens had larger clutches and were more herbivorous than IAS-threatened and worldwide birds, while IAS-threatened birds were more insular endemic from the Australia region than alien and worldwide birds. IAS-threatened species showed opposite strategies to alien birds regarding traits related to diet, origin, and reproduction. Further exploring traits associated with impact magnitude, we found that alien birds with high impact had a generalist behavior and an animal-based diet. Although traits were a strong basis to distinguish aliens from IAS-threatened birds, they did not differentiate the impact type. In conclusion, by emphasizing differences relating to the density distribution of bird groups in a functional space, we opened new opportunities to identify the role of birds in biological invasions.

Scripts and data for reproducing the results obtained by Marino & Bellard (2023) in the paper "When origin, reproduction ability, and diet define the role of birds in invasions"

The first script computes the axes of the multidimensional functional space based on the traits of both alien and IAS-threatened birds. The second script performs the statistical analyses based on the functional space and creates figures 1 and 4. The third script performs the trait-by-trait analysis and creates figures 2 and 3. The last script describes the steps implemented for evaluating the prediction of impact type based on the position of birds in the functional space.

The dataset has been collected as described in the method section of the associated paper.