European starlings were introduced to Buenos Aires in 1987 and may threaten other cavity-nesting birds. Researchers studied starling density in urban parks, finding an average of 2.21 individuals per hectare. Starlings were more common in parks with larger areas and more palm trees, but fewer trees overall. They were also associated with tipu trees. However, their presence and abundance did not affect the diversity of other bird species in the parks. Starlings were observed interacting with native species, potentially using Rufous Hornero nests.