1.  nestling(n = noun.animal) baby bird - young bird not yet fledged;
is a kind of young bird

2.  nestling(n = noun.person) child, fry, kid, minor, nipper, shaver, small fry, tiddler, tike, tyke, youngster - a young person of either sex; "she writes books for children"; "they're just kids"; "`tiddler' is a British term for youngster"
is a kind of juvenile, juvenile person
has parts: child's body
has particulars: bairn, buster, changeling, child prodigy, infant prodigy, wonder child, foster-child, foster child, fosterling, imp, monkey, rapscallion, rascal, scalawag, scallywag, scamp, kiddy, orphan, peanut, picaninny, piccaninny, pickaninny, poster child, kindergartener, kindergartner, preschooler, silly, sprog, bambino, toddler, tot, yearling, urchin, street child, waif

1.  A young bird which has not abandoned the nest. Piers Plowman. [1913 Webster]

2.  A nest; a receptacle. Bacon. [1913 Webster]

   Newly hatched; being yet in the nest. [1913 Webster]

nestling, n. a bird that is too young to leave its nest.

N  infant, babe, baby, babe in arms, nurseling, suckling, yearling, weanling, papoose, bambino, kid, vagitus, child, bairn, little one, brat, chit, pickaninny, urchin, bantling, bratling, elf, youth, boy, lad, stripling, youngster, youngun, younker, callant, whipster, whippersnapper, whiffet, schoolboy, hobbledehoy, hopeful, cadet, minor, master, scion, sap, seedling, tendril, olive branch, nestling, chicken, larva, chrysalis, tadpole, whelp, cub, pullet, fry, callow, codlin, codling, foetus, calf, colt, pup, foal, kitten, lamb, lambkin, aurelia, caterpillar, cocoon, nymph, nympha, orphan, pupa, staddle, girl, lass, lassie, wench, miss, damsel, demoiselle, maid, maiden, virgin, hoyden, infantine, infantile, puerile, boyish, girlish, childish, babyish, kittenish, baby, newborn, unfledged, new-fledged, callow, in the cradle, in swaddling clothes, in long clothes, in arms, in leading strings, at the breast, in one's teens.