266 PUFFINUS CHLOROKHYNCHUS. 



All Petrels appear to be perfectly at borne in all weatbers on 

 the vast ocean expanse ; and the present species forms no 

 exception to this rule. Solitary individuals are frequently seen 

 flying across tbe track of vessels passing through the trade- 

 winds ; they come in sight, perhaps, away on the weather-beam, 

 shearing over the billows, one wing up and then down, with 

 great speed ; in a few minutes they will have crossed ahead 

 of the ship or flown round it at a distance, making their way 

 off to leeward, and disappearing as rapidly as they came in 

 sight. Their flight is performed by swaying the body as it were 

 from side to side, with the wings outstretched, and not 

 flapping, but turned up successively from the horizontal, the 

 course after each sudden inclination being downward and 

 then up again with a rapid sweep, overtopping the waves, and 

 instantly dropping again into the succeeding trough of the sea. 

 They feed on mariue substances, oily matter, the fat of 

 whales when it can be procured, and any garbage they may 

 find floating on the water. They sit buoyantly on the water, 

 and must, of necessity, sleep in that position, possibly reposing 

 a good deal by day. 



JSidification. — The Green-billed Petrel breeds at Round Island, 

 Mauritius, at Rodriguez, and probably other islands in the 

 Indian Ocean. Mr. Edward Newton, who visited a breeding- 

 place of this species at the first-named island, gives an interest- 

 ing account of it in the Ibis, 1861, p. 181, stating that there 

 is a large colony at the north-east of the island, although 

 they are spread over the greater part of it. He observes that 

 they are as tame as the Tropic birds but not so harmless. 

 " They breed/' he says, " under stones, and bite most awfully 

 if they get a chauce. The only way to get them out and take 

 their single egg is to contrive to turn them round, so that one 

 can grab their folded wings and tail. If dropped on the ground 

 they will run about, and for some time will not try to fly ; but 

 if thrown into the air, they will glide down gently towards the 

 sea. On going near any rock where there may be a dozen or 

 two, one bird seems to give the alarm, and a chorus of the 

 most extraordinary sounds immediately proceeds from under 

 the ground. I hardly know what to compare it to, as there is 

 nothing like it, except, perhaps, the noise made by cats when 

 they set up their backs and squall. ...It is kept up for a minute 

 or two, and increases when the individuals are hauled out in 

 the manner above described." Two eggs of this Petrel from 

 Round Island, for an examination of which I am indebted to 

 Mr. Foottel, of Croydon, are elongated ovals, one slightly 

 broader than the other, and both a little pointed at one end ; 

 they are dull white and smooth in texture, measuring 2*57 by 

 151 and 23 by 1 53 inches. 



