BIRD ROOKERIES OF TORTUGAS BARTSCH. 481 



alighted on the nest and began to brood the egg in comfort. On my return 

 several hours later it was still sitting quietly on nest. 



On the second day after this (when this same bird was at the nest again) 

 I lowered the nest back to 10 centimeters, its first vertical position. On return- 

 ing the bird alighted squarely on the nest, maliing perfect adjustment, i 

 scared the bird away. On its return the bird again adjusted accurately. I 

 next moved the nest baclj to the height of 100 centimeters. Bird returned and 

 alighted on egg and adjusted to it before I could get back to my position in 

 the bushes. Adjustment in the vertical plane is made with exceeding rapidity 

 and ease. 



I then moved the nest 100 centimetei-s to the east, leaving it 100 centimeters 

 above the ground. Behavior of bird very interesting. Would not alight on 

 nest. Alighted at the former ground position. After a long time flew from 

 the old position and up to new position of nest. Immediately hopped down 

 and began a most peculiar performance. Bird would hover in space, attempting 

 to adjust to the nest in the air at its former position and height. It would 

 then fly away again and come back to the old position and try to alight in 

 space. This was done 20 times. At the end of 20 minutes the bird alighted 

 upon the pan in its new position and sat down on egg. I then scared the bird 

 away 5 successive times, to see if it would alight immediately upon the pan. 

 Each time on returning the bird alighted at the old ground position and pro- 

 ceeded from this point to the new position of the nest. 



I then put the pan back in its old position. Bird returned and alighted on 

 pan immediately. In this position I then raised the pan to a height of 200 

 centimeters. This raised the nest well up above any of the surrounding bushes. 

 This did not cause the bird the slightest disturbance. I forced it to make 

 three or four adjustments to the nest in immediate succession. It made them 

 all -with equal precision. 



Watson tells us that the liabit whicli he has called the sunning 

 reaction in the noddies, while present to some extent before the 

 appearance of the 3'oiing, shows itself in completed form as the 

 development of the young progresses. He also states that he has 

 never seen sooties roosting upon stakes and buoys, etc., but that " the 

 sooty always leaves the island and returns to it without at any time 

 having ceased its flight. This seems rather remarkable when we 

 take into account the fact that the sooty leaves the island in the 

 earlv morning and oftentimes does not return until toward night- 

 fall." 



At times, however, the}^ do rest in elevated positions, as shown in 

 plate 4, in which a group of sooties is occupying the tops of a bunch 

 of bay cedars. 



When flying low over the water to the fishing ground the sooty 

 resembles the black skimmer in its flight to such a remarkable degree 

 that I have very often been forced to pick up my glass in the hope 

 of listing this bird for the Tortugas region. The fishing is done by 

 quickly picking up such small fry as may be forced to jump above 

 the surface by pursuing larger fish. The birds may be seen fishing 

 singly or sometimes a hundred or more of both noddies and sooties 



