c6 Wheelock, Regurgitative Feeding of Nestlings. It 



be content with investigating the crops of the nestlings immedi- 

 ately after feeding. This was done in all cases whether watched at 

 close range or not. As soon as possible after the parent bird had 

 given the meal and left the brood, we took one of the little ones 

 up and by touching it gently with a feather induced it to open its 

 bill. Unless fed to a surfeit the nestling responded eagerly ; and 

 the feather, trimmed to a blunt point, was thrust into the throat, 

 turned once and withdrawn. Usually sufficient food adhered to 

 it to be placed on a slide and examined under a microscope if 

 necessary. Whenever it was found impracticable to insert the 

 feather we forced the young bird to disgorge by a slight pressure 

 on the gullet. Often the skin of the crop was so distended and 

 so transparent that it was possible to judge of the condition of its 

 contents from an external examination. Usually the internal ex- 

 aminations were limited to one a day for each young bird. 



Just here let me call your attention to a few salient points. 

 First. — In every case offered in evidence the record begins on the 

 day of hatching. Data obtained without knowledge of the exact age 

 of the young birds is incomplete, and while more or less valuable is 

 not sufficiently reliable to be used here. 



Second. — That in every case the crops of the young were exam- 

 ined within five minutes, usually within two minutes after feeding 

 was completed, and before any digestive process could have taken 

 place in the throat of the young. This is a most important point 

 — that the examination of the crop was made before any digestion 

 by the nestling could have been under way ; hence whatever state of 

 digestion the food showed must have been effected in the throat 

 of the adult before it was given to the young. Moreover, as soon 

 as any food was given in a fresh condition by the adult the fact 

 was at once apparent in the examination. In order to note the 

 rapidity of digestion, I experimented with a brood of Thurber Jun- 

 cos by feeding them fresh food and examining the contents of the 

 craw at ten minutes afterward. There was practically no change 

 in form and but slight change in substance, it being a trifle 

 softer, and more slimy. The same experiment was tried with 

 young Robins' with the same result. In the case of Crows and 

 Blue Jays digestion was somewhat more rapid. 



The first brood that I recorded as feeding by regurgitation was 



