From Longman Dictionary of Contemporary Englishnestlingnest‧ling /ˈnestlɪŋ, ˈneslɪŋ/ noun [countable] HBBa very young bird that cannot leave its nest because it is not yet able to fly
Examples from the Corpus
nestling• More aggressive than their cousins, Caspians may supplement their fish diet with other birds' eggs and nestlings.• Instead of going closer to the nest and finding the genuinely helpless nestlings, the killer followed the apparently helpless adult bird.• For a start, the nest, its eggs, its nestlings and its owners are all highly camouflaged.• All are roost sites except Salthouse, where there was a nest and the pellets collected came mainly from the nestlings.• I wanted to stay until the nestlings left. 