INTRODUCTION. 7 
or three days, the proper inference generally is that no more 
will be laid. If the egg of a Cow-bird (§ 17, III) be discov- 
ered, it should be taken home, or destroyed (at a distance from 
the nest), unless observations are to be made upon the young 
when hatched. 
§G. A method of finding nests, which may often be prac- 
tised with success, is that of “tracking” birds, when seen 
with food for their mates or material for building. It is gen- 
erally a wearisome and patience-exhausting process, and fre- 
quently causes disappointment. Ht may often be facilitated by 
the scattering of feathers, horse-hairs, string, cotton-wovl, 
straw, etc., in places where they will attract the attention of 
the architects, in whose work you are interested. The nests of 
woodpeckers may often be found, by tracing to their source 
the loud rapping of the builders, or by observing on the 
ground the chips, which are usually fresh (unless, as is rarely 
the case, the excavation be made in an unsound tree). 
§H. When you take eggs, pack them at once, bearing in 
mind that the smaller ones are very delicate, and even the 
larger ones easily broken.® If they are of the former class, 
having taken from the box most of the cotton-wool, leave a 
layer on the bottom, in which make a slight depression with 
the finger, and lay the first egg. The following rules should 
be observed : —(1) An egg must not come in contact with an- 
other, with the bottom, sides, or cover of the box. (2) The 
cotton-wool must be tightly packed. To paek it loosely is a 
®° Much danger will be obviated by blowing the eggs first, when practicable. 
If fresh eggs are allowed to grow cold, or to remain long unblown the contents are 
less easily removed. The reverse is said to be the case, when eggs containing em- 
bryos are left unblown for two or even three days. See §I and note. 
