THE FEEDING OF NESTLING BIRDS 193 



species, to man and to other animals in which man is economically 

 concerned. While all of this has also a scientific value, yet the 

 horizon taken in from the viewpoint of pure science has a vastly 

 wider field than that which is involved in an economic study. 



Without attempting to scan the entire horizon we may at 

 once select the limited field into which we now wish to inquire. 

 One of the subjects which has received a relatively small amount 

 of attention is concerning the behavior of birds, and its inter- 

 pretation; and particularly the behavior of birds during the 

 breeding period, about which there is so much to learn. It 

 is true that within recent years much more attention is being 

 given to this phase of ornithology ; but notwithstanding a rapidly 

 growing literature along this line, on many of the problems 

 there is not yet sufficient knowledge to enable us to safely 

 generalize. 



While other causes may have played a part in the slow 

 development of our knowledge of the behavior of birds, it seems 

 not unlikely that it is to be attributed, at least in part, to some 

 prejudice against the reliability of field observations. 



There are some problems which may be checked by laboratory 

 technic, and in such cases our knowledge cannot be complete 

 until such a check is applied. But there are some questions, 

 which from their nature, can only be studied in the field (with 

 respect to many species, at least). For example, there are many 

 matters of detail about the mating of the sexes, the building 

 of the nest, and the care of the young, etc., which cannot well 

 be examined in the laboratory. 



So when we consider the question of the feeding of nestling 

 birds it seems that our most important method of study, and 

 perhaps the only method in some cases, is to watch the process 

 in nature and record the observations. 



I will now review, insofar as my study of the subject permits, 

 the facts which have been ascertained concerning the manner 

 in which young birds are fed. 



A considerable number of birds, among which, of course, are 

 the Limicolae, are precocious, and forage for themselves from 

 3he beginning. Smith's paper on the Spotted Sandpiper (l) 1 

 reported the feeding behavior of sandpiper chicks for as early 

 a period as I know of. 



1 Numbers in parenthesis refer to bibliography, and page citations will sometimes 

 be given also. 



