IXSTIXCT AND INTELLIGENCE IN BIRDS 



54i 



from the gullet (Figs. 5 and 6), and the berries or insects come out 

 entire, but covered with slime, more than one bird being quickly served 

 at each visit. In woodpeckers and goldfinches, which are fed at longer 

 intervals, the food comes up in the form of a " pap " or " mash," prob- 

 ably from the stomach in part, to judge from the outlines of the neck, 

 and all are fed rapidly as before. 



The nestling gives the " opening " response, and shows its " food- 

 target,'*' while the parent, if a robin, vireo or one of many altrices, 

 "aims*" (Figs. 3 and 4) and inserts the food deep into the throat, 

 presses it gently down, and watches it, watches, we may say for the 

 swallowing reflex of the throat. If not quickly taken, the food is 

 whisked out and passed around, one bird after another being tried in 

 succession, until a throat with the proper reaction-time is found. There 

 is commonly no distribution of food among the offspring, on any other 

 basis than this. The youngster which can react most promptly, is thus 

 favored, because he holds up most of the food; accordingly he grows 

 fastest, and outstrips his competing nest-mates. The young cowbird 

 drives the children of its nurse quickly to the wall because it reacts 

 with greater vigor from the first, and interferes with any proper dis- 

 tribution of the food. It is not uncommon to see the same bird, usually 

 the larger and stronger one, fed two or three times in succession, but 

 the full gullet checks the swallowing reflex, and thus automatically ap- 

 plies a brake to the greediness of a nestling, which might otherwise 

 gorge itself to suffocation. 



Fig. 5. Cedarbied at Nest with full Gullet. First stage in reaction of young. 



