2^4 Papers from the Marine Biological Laboratory at Tortugas. 



TESTS WITH NODDIES ON RECOGNITION OF THE NEST AND NEST 



LOCALITY. 



The nest of the noddy is not individually recognized. I found that I 

 could exchange a large nest for a small one or vice versa; that I could tear 

 out the old nest and construct a rough one of bay-cedar limbs, etc., without 

 the noddy's reactions being in the least affected. I then made tests of the 

 following kind upon the nest locality, one of which I shall cite in detail : 



An isolated noddy nest, placed in the crotch of a limb near the stem of 

 the bush, was moved 3 feet farther out on the limb, but was still left in 

 plain sight. The noddy, on returning, flew to the old position of the nest. 

 After some delay it alighted on the nest. It then flew back to the old posi- 

 tion. It then flew to a limb a few inches above the old position of the nest 

 and waited there for a time. It then m^de 9 trips between the old position 

 of the nest and the new. After half an hour it settled down in the nest 

 in the new position and remained quietly brooding the egg for a few 

 minutes. It then became uneasy, got up, and made several more trips to the 

 old position and back to the new. Finally it settled down upon the nest in 

 the new position and made no further attempt to return to the old position 

 of the nest. I next made it a nest out of bay-cedar limbs and put it in the 

 old position, putting therein a sooty egg which I found at hand. On re- 

 turning, the bird naturally had the choice of going to its old nest and its 

 own egg in the new position, or going to a makeshift nest containing a sooty 

 egg in the old position. It went immediately to the old position and set- 

 tled down on the sooty egg with apparent satisfaction. These tests were re- 

 peated on other noddies with similar results. 



I conclude from these possibly insufficient data that the nest locality exerts 

 the stimulus for nest orientation and that the nest and egg as such are not 

 important factors in this situation. Whether or not this return to the old 

 position is accomplished in terms of visual data, my experiments do not 

 show. Provided the one limb is left which supports the nest, the rest of the 

 bush and the surrounding bushes may be cut away and the whole visual en- 

 vironment greatly altered without the birds' reactions being changed in the 

 least. 



TESTS WITH SOOTIES ON RECOGNITION OF THE NEST AND NEST 



LOCALITY. 



The study of nest and nest locality recognition are the most interesting 

 problems in the study of the life of the sooty. If one recalls the conditions 

 under which they lay their eggs, namely, in open spaces and at distances apart 

 sometimes not greater than 10 to 14 inches, one can not but admire the 

 exactness and ease with which the sooty approaches its own nest. I have 

 made numerous experiments upon the distance to which the sooty nest can 

 be moved without disturbing the habitual adjustment of the birds to it. 

 These tests, while not satisfactory as regards the determining of the sensory 

 factors entering into this function, at least will serve to show the nicet}' with 

 which the sooty makes its adjustments to the nest locality. 



