Published on 01 June 1912 in Letters

SIRS,–Mr. Dunlop’s interesting article on ” I n c u b a t i o n ” in your last number (Vol. V., p p . 322-7) tends to throw a new light on a n old subject, b u t it seems to me t h a t the writer does n o t distinguish sufficiently between ” standing over the eggs ” and incubation proper. F o r instance, it is the common and normal practice among domestic pigeons for one parent or t h e other to be in constant attendance on t h e nest after the laying of the first egg, b u t incubation does n o t begin until the laying of t h e second egg forty-six hours later, a n d t h e young invariably hatch o u t practically simultaneously. Again, Moor-Hens(Gallinula chloropus) always hatch the whole of their brood a t the same time, and until the whole clutch is laid the eggs are never warm. With> regard to the Grebes, t h e writer seems rather confused. The covering of the eggs b y vegetation is surely a more effective mode of concealment than the bird herself, a n d as the bird has n o special means to drive off” would-be enemies, her presence before incubation commences would be a source of danger rather t h a n of safety. The presence of the parent bird standing over the eggs and thereby concealing them is undoubtedly

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