96 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



the one area and then, when the available nests have all been made 

 use of, the cuckoo removes to another area, generally close by, even- 

 tually often returning to the original one later in the season and 

 again cuckolding other nests of the same fosterer. 



There can, I think, be no doubt that a cuckoo brought up in a nest 

 of a certain fosterer will deposit its own eggs in nests of the same 

 bird. This theory seems now to be one generally accepted, and cer- 

 tainly my experience goes to confirm this, and in my own collection 

 I have eggs of a very definite type taken for over 30 years in the 

 nests of the same species of fosterer in the same district. 



Eggs. — The eggs of the Khasia Hills cuckoo are of very many and 

 beautiful types of color and character of markings, while the eggs 

 of each individual cuckoo, though varying slightly inter se, do not 

 show so great a variation as is found in the eggs of single clutches 

 laid by many species of Passeres or other orders. 



Among the most common types of eggs are, naturally, those that 

 have been evolved to assimilate with the eggs of the birds most 

 frequently employed as foster parents. Among these may be men- 

 tioned the following: 



An egg with a white ground lightly marked, chiefly at the larger 

 end, with specks, spots, or small blotches of red, reddish brown, or 

 brown. These eggs are excellent counterparts in all but size of the 

 eggs of the fantail warbler, in whose tiny nest they are usually 

 deposited. 



The next commonest type has the ground color more or less dis- 

 tinctly tinged with reddish and is rather more profusely marked 

 with larger blotches of various shades of red-brown. These are 

 normally deposited in the nests of various species of Suya, or brown 

 hill warbler, the most common types of whose eggs agree well with 

 those of the cuckoo. 



A third and common type of cuckoo's egg has the ground color 

 a beautiful salmon-pink or buff -pink and has the surface freckled 

 with deeper reddish ; in some cases so finely and thickly that the eggs 

 appear at first glance to be unicolored; in other cases more or less 

 boldly, though sparsely, covered with reddish brown and underlying 

 faint marks of gray or pale purple. These eggs agree well with 

 various types of eggs laid by the verditer flycatcher and, even still 

 more so, with those of the beautiful niltava {Niltava sundara)^ 

 while it is in the nests of these birds we find them deposited. 

 Cuckoos, however, that normally deposit their eggs in the nest of 

 these birds seem regularly also to cuckold the large niltava {N. 

 grandis) and the white-tailed chat {Muscisylvia notodela), which 

 lay the same colored eggs and make similar cup-shaped nests of 

 living moss, built in exactly similar positions in holes in banks and 

 amons: boulders. 



