BIRDS. 
Puate XIU. 
Heads of McCormick’s Skua (Megalestris maccormickt) at various ages. Fig. 1, of 
nestling when first hatched, with the egg-scale still attached to the upper bill; fig. 2, 
nestling at about two weeks, showing the rapid growth of the bill; fig. 3, fledgling at 
about seven weeks, when the bird is just beginning to use its wings; fig. 4, young adult 
of the first year; fig. 5, adult at the end of summer, but before the moult. 
