62 BULLETIN 621, U. S. DEPARTMENT OF AGRICULTURE. 



Other insects. 



Other orders of insects are poorly represented in the food of nestling- 

 crows. As in the case of the food of adults, craneflies (Tipulidse) are 

 the most important of the Diptera. Of bees, ants, and wasps (Hy- 

 menoptera), young crows take only a small quantity, 0.73 per cent, 

 but include many of the species listed under the food of adults (see 

 p. 24). Other insect forms occurred in only negligible quantities. 



Spiders constitute one of the most important food items of the 

 young crow during the early days of its existence. In fact for the 

 whole period of its nestling life these creatures form nearly a tenth 

 (9.68 per cent) of its diet. They were present in 471 of the 778 

 stomachs, in man}^ of these high percentages being recorded. One 

 newly hatched bird had subsisted on spiders alone; in 7 stomachs 

 they comprised over 90 per cent of the food ; while in 32 additional 

 stomachs they formed over half pf the contents. No instances of 

 very large numbers occurring in single stomachs were noted, 3 or 

 4 of the large wolf spiders so frequently eaten usually being suffi- 

 cient to satisfy all needs. In only 4 cases were more than 10 spiders 

 eaten; the highest record — 15 — was that of a callow young bird. 

 The avidity with which very young crows eat these arachnids is well 

 shown by the following summary: One hundred and twenty-six 

 nestlings, ranging in age from 1 to 4 days, and picked indiscrimi- 

 nately from the material at hand, had been fed on spiders to the 

 extent of a little less than a fourth of the food (24.5 per cent) ; in 80 

 others, 5 to 9 nine days old, spiders formed 11.6 per cent; and in 

 125, 10 or more days old, only 4.8 per cent of such food was recorded. 

 In the first of these three groups only 8 of the 126 failed to have 

 at least a trace of a spider in their stomachs; in the second series 

 12 out of 80 did not feed on them ; while in the third lot, including 

 many birds that were fully fledged, only about half (59 of 125) 

 had taken them. In feeding on the different families of spiders, 

 young crows followed closely the preferences exhibited in the 

 food of their parents (see p. 25). 



CRUSTACEANS. 



The greater part of the crustaceans eaten by the young crows 

 examined consisted of crawfish, which were taken in approximately 

 the same quantity (1.78 per cent) as recorded for the parent birds 

 during the same period. One nestling secured in Illinois had its 

 stomach practically filled (98 per cent) with this food, and in 27 

 others these crustaceans made up more than one-fifth of the stomach 



