INCA DOVE 447 



Plumages. — The following observations on plumage changes under 

 artificial conditions are of great interest and possible significance, 

 and are therefore recorded here. William Beebe (1907) subjected 

 with other birds some Inca doves to a warm, superhumid atmos- 

 phere and found that the plumage, with each succeeding molt, 

 became darker and developed iridescence. He says: 



When the concentration of melanin has reached a certain stage, a change 

 in color occurs, from dull dark brown or black to a brilliant iridescent bronze 

 or green. This iridescence reaches its highest development on the wing coverts 

 and inner secondaries, where, in many genera of tropical and subtropical doves, 

 iridescence most often occurs. 



In other words, by subjecting the Inca dove, which belongs in a 

 genus of tropical origin, to the humidity of the Tropics, it reverted 

 back in the lifetime of the individual to an ancestral type. This 

 is certainly a most surprising result and the experiment should be 

 repeated. Mr. Beebe's skins of Inca doves showing these remark- 

 able changes are on exhibition in the park of the New York 

 Zoological Society. 



[Author's note: I have never seen the nestling of this dove. 

 A small young bird, about two-thirds grown, in juvenal plumage 

 is much like the adult; it is more heavily barred with black or 

 dusky on the breast and flanks, with more buffy color on the belly ; 

 the feathers of the back, scapulars, and wing coverts have a heavier 

 terminal black bar and a subterminal band of " cinnamon-buff." 



A. J. Van Kossem tells me that the postjuvenal molt occurs soon 

 after the young bird attains its full size; and that the complete 

 postnuptial molt of adults comes at any time between July and 

 October, inclusive, with individual variation.] 



Food. — "Weeds abound in back yards and near dwelling houses 

 and barns, and in eating the seeds of these plants Inca doves give 

 good service. They also eat wheat and other small waste grains that 

 have fallen, but they are apparently unable to manage whole Indian 

 corn. Their familiarity permits them to mingle with poultry and 

 partake of their food. 



Water is, of course, an essential part of their diet, and reference 

 has alreacty been made to the extension of their range in times of 

 drought in order that they may obtain water. M. F. Gilman (1911) 

 says : " They are rather dainty in their drinking, rarely using the 

 chickens' drinking vessel but perching on the hydrant and catch- 

 ing the drops of water as they leak from the pipe. To do this 

 they nearly have to stand on their heads, but that does not bother 

 them at all." 



Behavior. — In summer these birds may be seen singly or in pairs, 

 or rarely in family groups, but in fall and winter they gather in 

 small flocks, which sometimes number as many as 50 individuals. 



