94 Bird - Lore 



Nevertheless, Pycraft, in a recent article (Pop. Sci. Monthly, December,. 



1902), advances the theory that all birds were originally 



arboreal and praecocial, and that, because of the danger of 



Theory , ,,. , . , • 1 l • u 



falling, etc., to which praecocial young, born in trees, would 



be exposed, the parents of those that remained praecocial descended to 



the ground to lay their eggs ; while the young of those birds which did 



not make this change either perished or gradually became altricial. Under 



the latter supposition there would evidently be a need for a corresponding 



change in the character of the nest, which would then become designed 



to hold not only eggs but young birds. 



Mr. Pycraft finds support for his theory in the development of the 

 wing of chickens and some other gallinaceous birds, which frequently 

 have a claw on the thumb and, in the embryo, one on the index finger; and 

 in the absence of the outer flight feathers from the first plumage, leaving a 

 free finger-tip ; all characters which suggest a former arboreal mode of life. 



The theory may be accepted for certain species, but the discovery of 

 Archaeopteryx would not seem to warrant us in assuming that all the 

 ancestors of birds were arboreal. We cannot assert that no birds have 

 been derived from either terrestrial or aquatic ancestors, a line of descent 

 which would have a most important bearing on the condition of the young 

 at birth of existing species, and, consequently, upon the character of their 

 nests. 



HINTS FOR THE STUDY OF THE LIFE OF THE NEST 



With a hope that they may be of assistance to students during the 

 nesting season, we append here, in advance of the publication of the 

 succeeding papers of this series, some suggestions for a study of birds 

 during the period of incubation and care of the young. 



Some form of blind, in which one may conceal oneself near the 



nest, is essential if one would study the home-life of birds 



Need of a , . ^ , . . , , n- • <• 



at close range. After struggnng with a clumsy arrair of 



sticks, wires arid canvas, I finally hit upon a very simple 



and effective structure, easy to make, to carry, and to erect. It consists 



of a good -sized umbrella, a sharp stick about three feet long, and some 



light green material. Cut the material into six- or seven-foot lengths 



and run them together until their united breadth equals the circumference 



of the open umbrella. Run a strong tape around what will then become 



the top of the cloth ; draw the ends until the remaining opening is 



about five inches in diameter, and then tie them. Stick the end of the 



closed umbrella into this five-inch hole and open it, when, as the folds 



of the cloth are adjusted, they will fall evenly from all sides of the 



umbrella and make a circular tent. Drive the three-foot stick a few 



inches into the ground, and fasten the umbrella handle to it with two 



