Vol. II, Pt. I] GIFFORD— BIRDS OF THE GALAPAGOS ISLANDS 27 



what is probably the first prenuptial moult, involving the wings 

 as well as the body. The newly-acquired feathers of the top 

 of the head are darker than those of adults taken at the same 

 time, and the ventral aspect of the body-plumage is browner. 



Five adults from Oneal Rock, taken July 27, 1905, are in 

 nuptial plumage somewhat abraded, and showing no indica- 

 • tions of recent feather-growth, except in one case, where a pin- 

 feather was found in the side of the neck. 



Nine adults from Clipperton Island were taken on the 

 breeding-ground, August 10, 1905. In No. 1416, male, the 

 moult is in full progress. New primaries have replaced all 

 but one of the old ; new tail-feathers and new body- feathers 

 are appearing. The white downy teleoptiles beneath the 

 contour feathers are also being shed. Six other specimens 

 show the moult under way; in the most it is just started, two 

 or three pin-feathers usually appearing at the base of the hind 

 neck. Two remaining specimens show no moult and are 

 comparable to the specimens from Oneal Rock. Without a 

 doubt, the moult which is beginning is the postnuptial. Two 

 individuals taken at sea near Clipperton Island on August 8, 

 are in the same stage as those from the island ; one shows con- 

 siderable new feather-growth, while the other exhibits but one 

 pin-feather. 



No. 1412, captured on August 3, ten miles north of Clipper- 

 ton Island, has a great many remarkably abraded and faded 

 feathers in the back, wings, and under parts. The new 

 plumage is that of the adult, as shown by the feathers of the 

 top of the head. The question is whether the worn feathers 

 are of an immature or of an adult plumage, also whether the 

 bird has not skipped a moult, or at most undergone only a 

 partial moult. The extremely dilapidated condition of the 

 old feathers would seem to indicate something of the sort. 

 Furthermore I can find no feathers that may be attributed to 

 a plumage appearing between the much worn one and the pres- 

 ent new one. 



In adults from Cocos Island taken during the first half of 

 September, 1905, the postnuptial moult is in progress; pri- 

 maries and rectrices are being renewed in some instances, as 

 well as the body-plumage. In certain cases the moult is just 

 starting. 



