(noun) - (1) The smallest of a brood. Formed like the old word nescook, from the Anglo-Saxon nesc . . . tender, delicate . . . Other derivatives of this word have a similar sense in other provincial dialects. Grose's Provincial Glossary has "Nestling, the smallest bird of the nest or clutch; called also the nestlecock or nestlebub" . . . In Devonshire . . . nestledraft is "the last and weakest child of a family" . . . The least pig of the litter is called a cadma or a whinnock in the southern counties and an anthony pig in Kent.
--G.C. Lewis's Glossary of . . . Words Used in Herefordshire, 1839
(2) The weakest bird of a brood is called neest gulp; the youngest or weakest pig of a litter is called the barra-pig; the youngest of other animals, pitman or pinbasket. In Somerset, according to Jennings, nestle tripe is the "weakest and poorest bird in the nest; applied also to the last born and usually the weakest child of a family; any young, weak, and puny child and bird."