368 TJ. S. NATIONAL MUSEUM BULLETIN 211 



perceptibly finer as well as more profuse, being more like the markings found in 

 the eggs of the Baltimore and Bullock's Oriole. They also average somewhat 

 less in size. 



The average measurement of 98 eggs in the U. S. National Museum 

 collection is 31.60 by 22.49 millimetres, or about 1.24 by 0.89 inches. 

 The largest egg measures 34.29 by 24.64 millimetres, or 1.35 by 0.97 

 inches; the smallest, 27.94 by 21.59 millimetres, or 1.10 by 0.85 inches. 



Incubation. — Incubation consumes 14 days and is accomplished 

 entirely by the female. Here again, confusion exists among writers. 

 H. C. Oberholser (1938) states; "It takes about 15 days to hatch the 

 young, in which performance the male seldom assists, although he 

 does aid in taking care of the young." However, it is the universal 

 and confirmed experience of those who have studied the bird on its 

 nesting grounds that the male never assists in incubation and does not 

 aid in the care of the young. 



Audubon (1834) gives a curiously mixed account of the nesting 

 behavior, in that he intimated that both birds build the nest, which is 

 an error, and that when this is done, the male departs and shows no 

 further interest in the domestic proceedings, which is correctl He 

 states further that the male "places implicit reliance on the fidelity of 

 his mate * * * many pairs now resort to a place previously known 

 to them, and in the greatest harmony construct their mansions. * * * 

 Each pair choose their branch of smilax." Also that the birds repair 

 last year's nest if any of it still exists, but if not, "they quickly form 

 a new one from the abundant materials around." The reader cer- 

 tainly gathers the impression that both birds engage in nest building, 

 which is not the case. However, Audubon then observes that after 

 the eggs are laid "all of the male buds fly off together and leave their 

 mates to rear their offspring." Rev. John Bachman's observations, 

 so frequently of value to Audubon, who quotes him at length, bear out 

 this practice; they can be summarized by Bachman's statements that 

 he "never found the males in the vicinity of the nests from the time 

 the eggs were laid," and that "the females alone take charge of their 

 nests and young." The experience of present-day observers confirm 

 these observations, and although contemporary writers say remark- 

 ably little about the apparent refusal of the male to take any part in 

 nesting activities, the statements given in the account of the Florida 

 race (see p. 359) should be conclusive. 



Plumages. — Dr. Chapman (1922) writes: 



The difference between the sexes is more pronounced in the Boat-tailed than in 

 the Purple Grackle, the female of the former being a generally brownish bird 

 with small trace of the glossy plumage of her mate. Furthermore, she has a much 

 shorter tail. Young birds of both sexes resemble^ their mother. The post- 

 juvenile molt is complete. The female acquires a plumage essentially like that of 

 the adult, but that of the male is much duller than that of the mature bird. There 



