86 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



sho\AO(l none of the functional development of birrls about to breed. The mi- 

 gratory movements of these birds increased from May until September, when 

 there was an abrupt decrease in their numbers, only stragglers being seen after- 

 wards. Not only were the September and October birds in fresh plumage, 

 but those secured had their sexual organs enlarged as in birds in the flush of 

 the breeding season. As the shearwaters are known to breed from October to 

 March on oceanic islands in the south temperate zone, the case seems to be 

 a simple one. 



The southward movement of this species, which is reall}' its spring 

 migration, begins in September and the bulk of the flight is oyer 

 before the end of that month, though it is still to be found here in 

 diminishing numbers during October and November on both our 

 Atlantic and Pacific coasts, Mr. Loomis (1900) says: "These shear- 

 Avaters in transitu., were exceedingly abundant on the 23d and 24th 

 of September, Afterwards the species rapidly declined in the scale 

 of abundance, in October and November only stragglers appearing." 



Nesting. — Mr, F. Ducane Godman (1907) gives the following ac- 

 count of the nesting habits of this species : 



It breeds in great numbers on some of the small islands off the coast of New 

 Zealand, the nesting places being much harried by the natives, who esteem these 

 shearwaters as an article of food. The burrows on the Chatham Islands are 

 usually formed in peaty soil, running horizontally for three or four feet and 

 then turning. The nest, a rude structure composed of sticks and dead leaves, 

 is placed at the end of the hole. A single egg is laid, both sexes assisting in 

 the work of incubation, and when the parents return to roost on shore in count- 

 less thousands, the noise they make is deafening. If removed from their bur- 

 rows they flutter about on the ground for some time in a confused way, but 

 eventually make for the sea. 



Sir Walter Buller (1888) says of its breeding habits: 

 On the Island of Karewa and on the Rurima Rocks large numbers annually 

 breed, sharing their burrows with the tuutara lizard, and submitting, season 

 after season, to have their nests plundered by the Maoris, who systematically 

 visit the breeding ground when the young birds are sufficiently plump and fat 

 for the calabash. 



Eggs. — He also describes an egg as follows : " An o^^g^ supposed to 

 belong to this species, is ovoide elliptical in form, measuring 3,1 

 inches in length by 1.95 in breadth ; it is white, wdth a smooth sur- 

 face, but much discolored by soiling." Mr. A. J. Campbell (1901) 

 describes the single egg as " round oval in shape, texture of shell 

 somewhat coarse, surface minutely pitted and slightly glossy, colour, 

 pure white, but frequently more or less stained with dirt." 



The measurements of 34 eggs, collected from various sources, 

 average 74 by 48 millimeters; the eggs showing the four extremes 

 measure 81.7 by 49.2, 79 by 53.4, 58.5 by 42.5, and 60.5 by 42 

 millimeters. 



Young. — Sir Walter Buller (1888) in referring to the young says: 



Mr. Marchant informs me that he found this species breeding in burrows 

 near the summit of the Island of Kapita about the end of February. The 



i 



