Alien rose-ringed parakeets ( Psittacula krameri ) attack black rats ( Rattus rattus ) sometimes resulting in death

摘要

The rose-ring parakeet (Psittacula krameri) is one of the most successful invasive birds in its establishment worldwide. Studies addressing its potential impact on native biota mostly focus on birds and little is known about how these and other parakeet species interact with native mammals. Here, we report 21 aggressions of rose-ringed parakeets towards black rats (Rattus rattus) in urban parks in Seville (Southern Spain) and Tenerife (Canary Islands). Either solitary parakeets or, more often, groups of up to 18 attacked rats when they climbed trees close to parakeet nests. Most attacks ended when the rats descended to the ground. However, in two instances (9.5% of the aggressions) the attacks resulted in the death of the rats as a result of falling to the pavement. These observations add further complexity to a biological invasion, where introduced parakeets have negative impacts on a predator and thus, some native bird species may benefit from their antipredator behavior. More attention should be paid to the interactions between native mammals and the non-native parakeets introduced worldwide.