342 Papers from the Marine Biological Laboratory at Tortugas. 



but found them quite intractable. They were thrown into a state of absolute 

 terror every time I approached them. I kept them in captivity for 72 hours, 

 but they would neither eat nor drink. They fought me with all the vigor 

 of an adult. Fearing their death from starvation, I returned them to their 

 respective nests. The instinct of fear develops very early in these young 

 birds in the field. Even at 3 days, if one approaches a nest containing 

 a young noddy and attempts to pick it up, it will first disgorge and then strike 

 vigorously with its beak. It is almost impossible to tame either the young 

 noddy or the young sooty unless it is reared by hand from the first day. 

 Lloyd Morgan, Spaulding, and others are unquestionably right when they 

 affirm that young birds if taken early enough and reared by hand exhibit 

 little signs of fear. 



THE DEVELOPMENT OF THE YOUNG SOOTY IN CAPTIVITY. 



The young sooty is born in a very helpless state. ^ On the 7th of June I 

 took 8 young sooties, all born on that day. They differed slightly as regards 

 their development. This is due to the fact that the birds dwell for varying 

 lengths of time in the shell after it has become pipped. I have been passing 

 through the bushes when the eggs were beginning to hatch and have heard 

 quite lusty " peeping " and on looking about to discover the young bird 

 have found that the noise came from birds still in the shell. Whether they 

 are fed at this age or not I do not know. Sometimes they live as long 

 as 2 days in the shell with only the beak protruding. At this stage in their 

 development they make no response to the warning cry of the adults as they 

 do later on. They go on " peeping " lustily after the adults have flown. 

 The peculiar protective attitude of the young birds has been mentioned 

 already; that is, the ability to lie outstretched and perfectly motionless. If 

 left for a time in this attitude, they begin to " peep " as soon as the sun's 

 rays become oppressive. This means of protection persists until locomotion 

 makes possible a more efl:ective method. When the protective attitude disap- 

 pears and locomotion becomes possible, the bird nms to cover when dis- 

 turbed. Hiding is never in any sense complete. Indeed, the reaction seems 

 to be almost thygmotactic. The moment the young bird can put its head in 

 the crotch of a limb or get its body in contact with some solid object, loco- 

 motion ceases. 



First day: 



The young birds which I captured showed apparent signs of fear. Mov- 

 ing the hand rapidly near them, as in offering a piece of fish, caused them 

 to dodge quite noticeably. The instinctive cry is a lusty " peep-peep." 

 They are well developed, but clumsy. The wings droop and the birds 

 have difficulty in standing; coordinated sitting positions likewise are almost 

 impossible. The birds are somewhat hard to feed during the first day, but 



^ For supplementary description of field behavior of young and parent see p. 215. 



