charles] OBSERVATIONS ON ROBIX XESTS 83 



feeding. The cock robin did less than one third of the feeding 

 on this day. 



For the five days on which complete data were taken, the 

 number of feedings were as follows: 

 Day By Female By Male Total 



Sixth 22 44 66 



Seventh 39 46 85 



Eighth 54 31 85 



Thirteenth 64 30 94 



Fourteenth 86 16 102 



The data of feedings by hours, when plotted, reveal a rath- 

 er sharp maximum frequency of feeding from 4 to 7 p. m., a 

 more or less level period during the greater part of the day, 

 and a less pronounced maximum from 5 to 7 a.m. The great- 

 est number of feedings in any one hour during these five days 

 was 14; there was never an hour without at least one feeding: 

 the average number per hour (from 4 a. m. to 7:30 p. m.) during 

 the five days was 5.6. 



The maximum number of pieces of food given to the young 

 by the parents in one day with 444; the minimum, 278; the 

 average, 356. The average number of pieces brought in one 

 visit was 4. For the five days, lepidopterous larvae comprise 

 one half of the food pieces; earthworms, 28.8 per cent; ants, 6.6 

 per cent; Diptera, 5.7 per cent; and Coleoptera, Orthoptera, 

 Myriapoda, adult Lepidoptera and other winged insects the re- 

 minder. Certain species were especially prominent in the diet, 

 and of these, specimens were captured and identified as above 

 mentioned. Some of them are of considerable economic sig- 

 nificance. 



The weights of the three young birds increased very rap- 

 idly until about the tenth day, after which they remained prac- 

 tically stationary save for the nocturnal shrinkage and diurnal 

 gain. 



From the view-point of behavior, or comparative psychol- 

 ogy, some notes of interest were taken. Almost invariably, af- 

 ter feeding, the excrement was promptly voided, the parent 

 waiting for this act and usually swallowing the excreta. The 

 nest was not soiled. The sun shone directly upon the nest for 

 about one hour each day, during which time the female brood- 

 ed in striking attitude. At one time when the young had been 

 weighed in a bowl and the bo\\l had been placed upon the sill 



