THALASSIDEOMA BULLOCKII. Ill 



Sound in great numbers a few days before the ' Transit/ Towards the end 

 of January they commenced laying their eggs generally. By the second and 

 third weeks of February the incubation of the eggs was usually far 

 advanced ; and a day or two before we left the island, Capt. Fairfax sent me 

 a young bird recently hatched. The tarso-metarsal joint is not elongated in 

 the chick. I failed to find the eggs of Thalassidroma melanogaster ; the birds 

 occurred to me only in pairs. 



'' It may be well to explain that Petrels sit in their holes in pairs until 

 the egg is laid. Then usually only one bird is found at a time upon the nest 

 until the young are hatched ; and soon after they have issued from the egg 

 the young are found alone during the day. For whilst incubation is m 

 progress, the bird not upon the nest is either asleep in a siding or branch 

 of the burrow or (more commonly) is spending the day at sea ; and when 

 the young are a day or two old, both of the parents absent themselves durmg 

 the day, and only return at night for the purpose of feeding them." 



