THE BIRD DEPARTMENT 



539 



That molting is not confined to birds is well recognized 

 and its homology to the " shedding of the skin " in reptiles 

 and amphibians is conceded. Of course, the snake or the 

 salamander does not actually shed its skin but merely 

 the hard outer cuticle. This cuticle, as in the case of the 

 birds' feathers, when fully formed is a dead structure and 

 it is inelastic. Consequently, as the snake or salamander 

 grows, this " shell " becomes too small for it and must 

 be replaced by a larger one. The more food one of these 

 cold-blooded animals consumes, the more rapidly it grows 

 and the more often it has to molt. It is not seriously 

 discommoded by the process, however, except for a short 

 time when the loosened cuticle over the eye becomes 

 opaque and renders it nearly blind. When this occurs the 

 animal rubs its nose against a stone, splitting the hard 

 cuticle and then gradually wiggles itself free, ieaving the 

 skin entire, a sort of a ghost of its former self. 



With birds the molting is a more serious matter. It 



ANOTHER PAIR CF HOUSE SPARROW S 



These birds are now in their winter plumage. The black spot on the throat 

 of the male is largely concealed by the gray tips of the feathers. 



requires far more energy to grow a new set of feathers 

 than merely to form a new cuticle, in fact, so much so 

 that most of the other activities must stop and the bird's 

 entire strength be given to molting. As a result song 

 ceases, fighting and display are never indulged in, and nest- 

 ing activities are completed and out of the way. The birds 

 retire to the thickets and move about only in search of 

 food. It is a period of sickness or indisposition and the 

 birds shun each other's company. During the molting 

 time many birds practically disappear and are nowhere to 

 be seen for several weeks. The red-winged blackbirds, 

 for example, are very abundant in all the marshes until 

 the last of August. Each evening they can be seen flying 



in large flocks to roost in the marshes and each morning 

 leaving again to feed on the upland fields. The sexes 

 separate in flocks by themselves and show little interest 

 in each other. Suddenly the male birds disappear, shortly 

 the females follow and there ensues a period of several 

 weeks when no blackbirds are seen either morning or 

 evening, nor are they to be seen during the day about the 

 marshes. In a few weeks they appear again and this time 

 in even larger numbers than before, for they have been 



A YOUNG GREEN HERON 



Showing the feather tracts and naked areas between found in all birds. The 

 bare areas are later entirely concealed by the overlapping of the feathers of 

 adjacent tracts. 



joined by migrating birds from the north. In former 

 years it was supposed that the early disappearance was 

 caused by the resident birds leaving for the south and 

 that the reappearance of blackbirds announced the arrival 

 of birds from the north, but the unaccountable part of the 

 story was that although the August birds were supposed to 

 be leaving for the south, they never arrived. Instead, the 

 blackbirds in the south likewise disappeared and were 

 supposed to be moving eastward to the rice fields. The 

 mystery of their disappearance, however, can easily be 

 explained by anyone who will venture out into the heart 

 of the larger marshes during the first of September, for 

 there he will find, after sufficient search, large flocks of 

 short-winged, short-tailed blackbirds skulking about the 

 more open areas and hesitating to fly far. For it is at this 

 period that they are just completing their molts by the 



