Page:Bird-lore Vol 05.djvu/107

 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 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 Archmopteryx 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.

Ri'rraft 'x Tbeary

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 0 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 stuty the home-life of birds at close range. After struggling with a clumsy affair of sticks, wires arid canvas, 1 finally hit upon a very simple and effective structure. easy to make, to carry. and to erect. It consists of a goodrsized umbrella, a sharp stick about tiree feet long. and some light green material. Cut the material into six? or sevenyfoot 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 tie 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 even y from all sides of the umbrella and make a circular tent. Dri\e the three-foot stick a few inches into the ground. and fasten the umbrela handle to it with two

IVIHI 0/ (1 Blind