NORTHERN BLUE JAY 39 



plainly afraid of the mice. Coming to the table they would, with all 

 signs of fright, jerk back, flutter with the wings and fly away. It was 

 up to the old birds to take the mouse, fly with it to a nearby branch, and 

 begin to tear it to pieces. And then the young birds would come near 

 and were fed by the adults." 



Plumages. — [Author's note: The following abstracts are taken 

 from the manuscript thesis of John R. Arnold, referred to above. He 

 has made a thorough study of the plumages of the blue jay, and says 

 that the young are hatched naked and have no natal down at all. On 

 the eighth and ninth days the body plumage begins to break the feather 

 sheaths, and when the young bird leaves the nest, at an age of about 

 20 days, the juvenal plumage is largely grown and the bird is able to 

 fly. He describes this plumage as follows : 



"Pileum between cadet gray and Columbia blue. Feathers of forehead 

 black at base with bluish- white tips. Superciliary line grayish white. 

 Throat bluish white to white. Nuchal band black. Black of lores less 

 pronounced than in adult. Back and lesser wing coverts light to deep 

 mouse gray, tinged with blue. Wing and tail feathers as in first winter 

 and similar to adult. Breast and flanks smoke gray, belly and under 

 tail coverts white." 



A partial postjuvenal molt takes place when the bird is between 50 

 and 90 days out of the nest; this produces a first winter plumage that 

 is hardly distinguishable from that of the adult, though somewhat paler 

 and less violet on the head and neck, and with the bars on the tail less 

 pronounced. This molt involves the contour plumage and the lesser 

 wing coverts only. 



Adults have a complete postnuptial molt between June and September.] 



Food. — The blue jay eats almost every kind of digestible food ; like 

 its relative, the crow, it may be considered omnivorous. F. E. L. Beat 

 (1897), in an exhaustive study to determine the exact economic status 

 of the jay, published the results of an examination "of 292 stomachs 

 collected in every month of the year from 22 states, the District of Col- 

 umbia, and Canada." He says: 



One of the first points to attract attention in examining these stomachs was 

 the large quantity of mineral matter, averaging over 14 per cent of the total 

 contents. The real food is composed of 24.3 per cent of animal matter and 75.7 

 per cent of vegetable matter, or a trifle more than three times as much vegetable 

 as animal. The animal food is chiefly made up of insects, with a few spiders, 

 myriapods, snails, and small vertebrates, such as fish, salamanders, tree frogs, mice 

 and birds. Everything was carefully examined which m'ght by any possibility 

 indicate that birds or eggs had been eaten, but remains of birds were found in 

 only 2, and the shells of small birds' eggs in 3 of the 292 stomachs. * * ♦ 



