ON THE ALTERNATION OF SEX IN A BROOD 
OF YOUNG SPARROW HAWKS. 
Dr. R. W. SHUFELDT, C.M.Z.S. 
In the early part of May (1898) a collector sent me a brood 
of five nestling sparrow hawks (Falco sparverius), taken from 
their nest in the neighborhood of Washington, D.C. At the 
time of reception they were in excellent health and vigor, and 
all readily fed from the hand bits of raw beef that were offered 
to them. The quantity of such food each one could eat at a 
single meal, and the rapidity with which it was digested, were 
both remarkable facts. A pound and a half of beef was equally 
divided among them within a quarter of an hour, and was dis- 
posed of without any apparent inconvenience to them. Having 
kept them five or six days in a small basket in which an im- 
provised nest had been made, it was noted with surprise that 
this temporary habitation remained unsoiled by their excrement, 
which, however, was by no means the case with the floor for 
nearly a yard from the edge of the basket, and upon the walls 
of the corner of the room where the basket was kept, up for 
nearly an equal distance.. In this particular, nestling raptorial 
birds are at marked variance with such groups as the. 
Passeres and the Woodpeckers, for example, where the 
parents habitually carry away the excrement of their young, 
and drop it at a distance from the nest. On or about the 
sixth day I made a series of photographs of these young 
hawks, taking them singly, and in one instance two of them 
together, after which my son chloroformed the five and made 
a very excellent series of skins of them. Upon dissection and 
a study of this series a number of interesting points were 
brought to light. It was noted in the first place that the 
largest bird of the brood, and of course the oldest one, was 
nearly double the size of the youngest or last one of the series, 
while the three others graduated down, from the largest to the 
