COLOUR IN BIRDS AND QUADRUPEDS. 219 



stance where a different process takes place. This, however, affords 

 no proof of the truth of the assertion that all birds moult but once a 

 year, since it is now certain that the majority of birds moult twice a 

 year. I do not however consider it impossible, that even in regard to 

 this species some mistake may have occurred. These changes pro- 

 gress silently and rapidly, and unless watched with great care, are 

 effected without our observing the process. The males made their 

 first appearance this year in our rice fields, in scattered flocks, on the 

 5th of May ; and on that and the three following days I had an oppor- 

 tunity, through the politeness and attention of several planters, of exa- 

 mining fifty specimens. Nine-tenths of the birds were in full plumage, 

 and there was no appearance of their having moulted ; but in five or 

 six specimens, where the black colour on the breast had not been fully 

 restored, I perceived several places where rows of young feathers, still 

 sheathed, existed in spots of an inch or two in extent. These feathers, 

 instead of coming out yellowish brown, as is the case with the species 

 when they moult in autumn, were black, narrowly edged on the points 

 with brown. Whether the moult was accidental in these specimens, 

 or whether it extends to every individual in the species, I had no means 

 this spring of ascertaining ; certain it is, that the young feathers percep- 

 tible on the specimens sent with this communication, do not undergo 

 the process of the change from brown to black, which must be the case 

 if the colours of spring are imparted without afresh moult. 



Sylvia aesHva, Blue-Eyed Yellow Warbler. This species, in autumn, 

 is of a pale yellow colour, changing in spring to bright yellow, streaked 

 on the breast with orange. It probably undergoes this change within 

 the tropics. On the 27th of April I had an opportunity of examining 

 eleven specimens ; two of these were not in full plumage, and I ob- 

 served that in one instance the whole head was covered with new fea- 

 thers, and in another the young feathers on the back had recently been 

 produced, and were still enclosed in a tube. 



Fringilla cyanea, Indigo Bird. This is a rather rare species in the 

 maritime districts of Carolina, and breeds but sparingly in these parts. 

 On the 3d of May I obtained three male Indigo Birds. They were in 

 full song, and I was enabled to discover them by their notes. One of 

 the birds was in perfect plumage, and I could observe no evidences of a 



VI. — 3 E 



