Moulting and Replacement of Feathers

Abstract

IN a recent publication, Dr. Lowe¹ has described the peculiar moulting of penguins as due to new feathers pushing out their predecessors in rather widespread areas, and regards this as a unique feature of Sphenisciformes. Moulting in patches is certainly a rare occurrence under normal conditions in the majority of birds, but a new feather growing at the base of the old feather is the usual method of replacement during the moulting period. Dr. Lowe further says: “the intrusion of the tip of the new feather through the lower umbilicus of the old is interesting, because in birds in general as soon as the growth of the feather becomes an accomplished fact the lower umbilicus at the base of the calamus is definitely sealed, making the entry of a new feather an impossibility”. He continues by using this as one of the reasons for regarding the penguin as primitive rather than degenerate, and quotes Gadow that the only known exception to this general rule is in Struthiones, where the old feather is carried for some time at the tip of the new.