126 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



stones as large as I could lift on all sides of me, seldom failed iu capturing two 

 or three seated on their nests, either under the lowest stone or between two of 

 them. The nests, though of much the same materials as the ground on which 

 they were placed, seem to have been made with care ; they were of small bits 

 of stalks of plants, and pieces of hard, dry earth. Like the rest of the genus, 

 the stormy petrel lays invariably one egg only. During the daytime they 

 remain within their holes; and though the fishermen are constantly passing 

 over their heads (the beach under which they breed being appropriated for 

 the drying of fish), they are then seldom heard, but toward night become ex- 

 tremely querulous ; and when most other birds are gone to rest, issue forth in 

 great numbers, spreading themselves far over the surface of the sea. 



Mr. W, Eagle Clarke (1905a) gives a good account of the nesting 

 habits of this species, as foUov^s : 



The storm petrel is very numerous during the summer, when they fly noisily 

 about the islands during the nighttime. They breed on Eilean Mhor, and proba- 

 bly on the other islands, in abundance. Many chicks, some of them quite re- 

 cently hatched, were found during our visit in September, and we saw young 

 ones in every stage from a few hours' old (tiny balls of pretty lavender-grey 

 down) to birds full grown and fully feathered, except that they had a bunch of 

 down still present on the lower part o£ the abdomen. The old birds are entirely 

 absent during the daytime, leaving even the small chicks to take care of them- 

 selves, and do not return until darkness sets in, when they tend their young 

 and depart again early in the morning, probably to spend the day far out at sea 

 in search of food. We opened out a number of their nesting holes at all hours 

 of the day, but the old birds were always absent, except in one instance, where 

 the young had only recently emerged from the egg. Occasionally they visited 

 the lantern. They nest in the remains of the old building, in holes in turf, and 

 under stones among grass. The nest is a mere mat composed of dry roots, grass, 

 etc. I received a young one in full down, which had been taken on the 3rd 

 October ; probably the first egg of this pair had been taken or destroyed. 



The fact that eggs have been taken at various dates between May 

 and October has suggested the possibility that two or more broods 

 may be raised in a season, but probably such is not the case. 



Eggs. — Godman (1907) describes the egg as follows: "The egg is 

 white, with a sprinkling of minute reddish-brown dots, frequently 

 forming a distinct zone round the larger end." 



The measurements of 44 eggs, in various collections, average 27.() 

 by 21.3; the largest eggs measure 30 by 22 and 28.5 by 22.5; the 

 smallest eggs measure 26.2 by 21 and 29.5 by 20.5 millimeters. 



Rev. H. A. Macpherson (1898) says: 



The task of incubation is shared by both sexes, but It is usual to find only one 

 bird upon the egg. Probably the bird which is incubating is fed at night by its 

 mate, which has passed the day at sea. The egg of the storm petrel is believed 

 to be incubated for about thirty-five days. Mr. William Evans ascertained that 

 eggs of this species when placed in an incubator chipped on the thirty-third day, 

 while a chick hatched out upon the thirty-fifth day. 



Young. — The same writer gives the following interesting account 

 of the behavior and development of the young bird in confinement : 



