234 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



part in incubation and both share in the care of the young. Macoun 

 (1909) reports a nest in which both birds were sitting on the eggs at 

 the same time. The cavity of the nest was much larger than usual. 

 There were five nearly incubated eggs in the same stage of development, 

 indicating that these birds were male and female rather than two fe- 

 males. Occasionally three crows may be seen about the nest, but be- 

 cause of lack of sexual differences of plumage it is difficult to determine 

 whether they represent cases of polygamy or polyandry. There is 

 indirect evidence, however, that two females may be concerned. There 

 are a number of cases on record where two sets of eggs were found in 

 a nest that hatched on different dates. Jung (1930) found a crow's 

 nest on June 15, 1928, in Alberta, Canada, that contained three eggs 

 and one young about a week old. When the nest was visited the next 

 day a fourth egg had been added. Three crows were seen about the 

 nest and it is apparent that two of them were females, both of which 

 were contributing eggs to this communal nest. In other cases three 

 crows were concerned with a single nest, which contained a normal set 

 of eggs hatching on the same date. Here, it is probable, two males were 

 involved. 



Young. — The young when first hatched are pink or flesh color and 

 scantily clad with tufts of grayish clove-brown on the head, back, and 

 wings. At five days of age the eyes are open and the exposed parts of 

 the skin have acquired a brownish-gray color. At 10 days the principal 

 feather tracts are established by the rapidly growing feather papillae. 

 At this stage they assert themselves by loud clamorings for food, and 

 the presence of a nest may be revealed by their incessant calls, especially 

 as they grow older. When the young crows reach the age of 20 days 

 many of the contour feathers are unsheathed, presenting a dull black 

 color. Tufts of down still cling to the tips of these juvenal feathers, 

 especially in the region of the crown. The eyes are a dark blue-gray, 

 the scales of tarsus and toes are grayish black, the upper mandible or 

 maxilla is black, and the lower mandible is pale yellow or horn color 

 streaked with gray. The lateral basal portions of the gape are yellowish 

 orange. At this age tufts at the base of the bill are developed. 



After four weeks most of the feathers are completely unsheathed. 

 The young at this stage also show a marked change in behavior especially 

 in regard to a human visitor. Before this time they were passive but now 

 exhibit fear and offer resistance at being handled or lifted from the nest. 

 At this time they may stand on the rim of the nest or even leave to 

 nearby branches of the tree where they are fed by the adults. In the 

 course of another week they are capable of leaving the nest and making 

 their initial flight. If disturbed they may leave the nest before reaching 

 the age of five weeks. 



