Eurasian nuthatch
Common starlings will take over Eurasian nuthatch nest holes, reducing their breeding success. This is most likely to occur if the nest is high in a tree and there is a good local breeding density of the nuthatch. Introduced ring-necked parakeets may also compete with Eurasian nuthatches for nesting holes. The parakeets tend to occur in fragmented urban woodlands, while nuthatches prefer large old oak woodlands, which reduces the level of competition. Ornithologists conducting a 2010 Belgian study suggested that the problem was not so severe as to warrant culling of the parakeets.