Development and Care of the Young 189 



of any kind. 1 Audubon, who has probably recorded more facts 

 on the behavior of American birds than any other writer, does 

 not, I believe, mention this important function. The reason is 

 not far to seek, for without the possibility of close approach to 

 the nest, and the use of a convenient blind, such acts are difficult 

 or impossible to observe. 



The instinct of inspecting and cleaning the nest is mainly 

 confined to the great passerine and picarian orders represented 

 in this country by hundreds of species. It is a well-marked 

 trait in Thrushes, Waxwings, Vireos, Warblers, Orioles, Black- 

 birds, Woodpeckers, Wrens, and Titmice, to mention those 

 families in which it has been regularly observed. Gulls and 

 Terns, however, possess the cleaning instinct in a minor degree, 

 as I have observed on one or two occasions. 



The excreta of the young of most land birds leave the cloaca 

 in the form of white, opaque or transparent, mucous sacs. The 

 sac is probably secreted at the lower end of the alimentary canal, 

 and is sufficiently consistent to admit of being picked up without 

 soiling bill or fingers. The parent birds often leave the nest 

 hurriedly bearing one of these small white packages in bill, an 

 action full of significance to every member of the family. I 

 have seen the Oriole carry these packages a few rods from the 

 nest and drop them before alighting. The Bluebird and Red- 

 wing Blackbird take them a long distance before letting them 

 fall. Crow Blackbirds sometimes drop them in the water, and 

 House Wrens and Nuthatches implant them on the bark of 

 trees. 



Removing the excreta piecemeal and dropping it at a safe 

 distance is the common instinctive method not only of ensuring 

 the sanitary condition of the nest itself, but, what is even more 

 important, of keeping the grass and leaves below free from any 

 sign which might betray them to an enemy. 



Many other birds, of which I can now certify the Robin, 

 Catbird, Cedar Waxwing, Red-eyed and Warbling Vireos, King- 

 bird, Redwing Blackbird, Brown Thrush, Chickadee, and 



1 See the original and excellent Researches in Zoology, by John Black- 

 wall, 2d Ed., London, 1873. 



