NESTS AND NEST-BUILDING IN BIRDS 167 



with a definite end in view; spiders also by courtesy are said 

 to spin, but I do not think it can be proved that birds delib- 

 erately either spin threads or tie knots. I have a nest of the 

 oriole, which is a felt-work of fibers, shot in and out, through 

 and through, looped in almost every conceivable way, thousands 

 of them, and in a sense no doubt knotted at many points ; further 

 I watched the building of this nest, and I know that the work 

 was done with a speed that taxed every resource to follow it, 

 and that such looping or " knotting " as exists, far from being 

 deliberate, was the inevitable consequence of a stereotyped 

 method of work, comparable to the turning and molding move- 

 ments of a building robin, or gull. It is not necessary to empha- 

 size further the need of ample corroboration of such remarkable 

 statements as we have quoted, for much of the difficulty in 

 dealing with the literature of nest-building lies in the very lack 

 of such requirements. 



Although my own studies in the field have been limited to a 

 few common American birds, they are offered at the present 

 time in the hope of directing the attention of other students 

 to a most interesting but singularly neglected field. Not only 

 do we need careful observations on the many representatives 

 of the seventeen thousand or more builders of nests throughout 

 the avian world, but we need repeated studies on the work of 

 different builders of the same species as well as upon successive 

 operations of the same individuals in the same or successive 

 seasons. Data of this sort to be most satisfactory, should repre- 

 sent the whole phase of behavior or building activity from the 

 start to the finish of a given nest. In many cases, to be sure, 

 from one cause or another such observations are either extremely 

 difficult or impossible, but in other and equally important cases 

 they are easy, the time element only standing in the way of an 

 observer, who, like myself, is liable to be called away by other 

 duties before his task is finished. In the case of an oriole for 

 instance, it would mean to be on the ground, at a point where 

 the birds could be clearly seen and their movements followed 

 for the best part of three or even four days, or from the time the 

 site is chosen and the first threads are laid to the putting of the 

 last stitch in the " hammock." The importance of following 

 the activities of more than one set of builders is seen from the 

 records of the robins which will be given later. I have merely 



