Vol i909- VI ] Recent Literature. 213 



Similar observations are recorded on the behavior of the sooty during 

 the period of incubation, in which are noted changes similar to those re- 

 corded for the noddy, with the important exception that the shift at 

 the nest in the case of the noddy occurs about once in two hours, and in 

 the case of the sooty only once in 24 hours. The period of incubation for 

 the noddy is given as from 32 to 35 days; the period of incubation for the 

 sooty was found to be 26 days. 



The activities of both species after the egg is hatched are recorded in 

 similar detail. The young of the noddy are fed at intervals varying from 

 one to four hours, and those of the sooty every four to seven hours. 



An interesting part of the paper relates to experiments in testing the 

 ability of recognition between mates, and of the parents to recognize nest 

 and young. While it is perfectly evident that such recognition must exist, 

 and cannot with reason be doubted, Dr. Watson's tentative proof that such 

 is the case is of interest. Birds were taken from marked nests, and the 

 birds themselves were also marked with oil paints; while this process 

 caused disturbance in the relations of the birds for a short time, they soon 

 became reconciled to the new conditions. 



Experiments in relation to recognition of the egg showed that neither 

 species recognizes its own egg, as is well known to be the case with many 

 other birds. Both species, also, would submit to considerable changes 

 in the size and character of the nest, and even to a slight change in its 

 position, without deserting it, but not without obvious recognition of the 

 changed conditions. A large number of experiments have relation mainly 

 to the length of time required for adjustment to the new situation. Where 

 the environment was markedly altered the bird remained undisturbed so 

 long as the position of the nest was not disturbed. Says Dr. Watson: 

 " If one recalls the conditions under which they [the sooties] 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 her own nest." This certainly shows a high power 

 of discrimination, quite in harmony with the action of birds in general, 

 and perhaps renders not less wonderful, but perhaps less astonishing, the 

 ability of migratory birds to find their way back to their own former nest- 

 ing-sites after hundreds and even thousands of miles of migratory travel. 

 With such power of local orientation as all birds show in the matter of the 

 nesting-site, is it so very strange that they should be able — accidents and 

 stress of weather aside — to orient themselves on their migratory journeys? 

 While the exact nature of this ability may not be at present known, its 

 possession is beyond question. 



Dr. Watson's experiments on distant orientation are here for the first 

 time fully stated, but the principal facts have already become more or 

 less current. His comment thereon is disappointing inasmuch as no 

 explanation is attempted. But perhaps this was to be expected for, as 

 he says: "the facts obtained from them are extremely difficult for current 

 theories of distant orientation to explain." These experiments, briefly 



