io8 THE INFANCY OF ANIMALS 



are coloured alike — as, for example, in parrots and king- 

 fishers, the crows, and the robin. Thus we arrive once 

 more at a phase where offspring and parents wear a livery 

 of the same hue, but of a higher plane of development. 



Reference has been made more than once already in 

 these pages to the fact that longitudinal stripes are, in 

 order of sequence, followed by the development of spots, 

 and occasionally of transverse bars. We find the same 

 sequence of events in young birds. The goshawk and the 

 peregrine falcon, for example, have the breast marked by 

 dark longitudinal stripes during their immature stages, 

 in the adult these stripes give place to narrow transverse 

 bars. Similarly, among the Passeres, there are numerous 

 families wherein the first plumage is distinguished both 

 by stripes and spots, the latter being the more con- 

 spicuous, the stripes forming but narrow lines down 

 the centre of the feathers. The thrushes, robins, and fly- 

 catchers may be cited as examples of this type of plumage : 

 and that this is an ancestral plumage is attested by the 

 fact that there are certain species of thrush, of the genus 

 Geochicla, wherein both adults and young are soberly 

 marked ; and without doubt these birds have retained the 

 plumage once common to all those species which now, as 

 adults, are so differently garbed. 



Our common gannet furnishes us with another curious 

 fact about the coloration of young birds. The downy 

 nestling is white : in due time it assumes a black livery 

 heavily spotted with white. Later this is discarded, and 

 a white livery is once more assumed, relieved only by 

 a delicate buff tinge on the head and neck, developed 

 during the breeding season, and black quills. This loss 

 of pigment during adult life is rare among animals. 



The sweet reasonableness of the view that the juvenile, 



