Few objects of natural history are more interesting than the nests of
birds. To the reflecting naturalist they open up a wide field for
inquiry. Speaking of the examination of birds, in the exercise of their
mechanical arts of constructing nests, Professor Rennie says: “This work
is the business of their lives—the duty which calls forth that wonderful
ingenuity which no experience can teach, and which no human skill can
rival. The infinite variety of modes in which the nests of birds are
constructed, and the exquisite adaptation of the nest to the peculiar
habits of the individual, offer a subject of almost exhaustless
interest.” The number and variety of the eggs of birds are curious
subjects of contemplation, and should be carefully noted whenever
opportunity offers. They are as essential to the personal history of the
species, as any other part of our inquiries.
The eggs are emptied of their contents by making a very small hole at
each end with a point. By blowing at one of the ends, the contents will
escape by the other, unless the young has been already formed; in which
case a larger hole must be made in the side of the egg, and the contents
removed with a small hook. The hole should then be stopped up by pasting
a little goldbeater’s leaf over it. The eggs are then either returned to
their nest, in which they ought to be cemented, or should be fixed down
by one side to cards, with the name and locality attached.
The best manner of conveying loose eggs to a distance, is to put some
cotton at the bottom of the nest, and then another layer above them. The
nests should all be put in separate boxes if possible, and so packed
that the pressure of the lid may not injure the eggs, or a box with
several compartments should be used, taking care that each is carefully
marked. It would also be of consequence to have the nests attached to
the branches, with those species which build on trees, which will enable
us to trace the ingenious means employed by those little animals in
constructing their habitations. In sending home specimens from a foreign
country, the seams of the box should be covered by pitched cloth to
protect them from the influence of moisture.
To preserve the shells of eggs, first take care to clear them of their
contents; get a small, fine-pointed common syringe, such as is sold in
toy-shops for a penny or twopence, and inject the specimen with water
until it comes out quite clean. When an egg has been partly hatched or
addled, the removal of the contents generally includes that of the
internal membrane or pellicle; this makes the shell weaker. When the
specimens are quite clean internally, and have become dry (which will be
in a day or two), take the syringe and inject them with a strong
solution of isinglass (with a little sugar-candy added to prevent its
cracking); blow this out again whilst warm. Let the shell get dry, and
then wash the outside with a soft wet cloth to remove saline particles,
dirt from the nest, etc. This method varnishes the inside, and the first
specimen on which it has been tried was the before-mentioned
hedge-accentor’s egg, which is to this day as bright in color as a fresh
specimen.
Also in a pair of nightjar’s eggs, of which species the delicate gray
tint is particularly evanescent, one was injected in the manner
described, and the other was not; in the first the gray is still
perfectly defined, in the other it has entirely disappeared. Eggs which
have lost their internal pellicle become strengthened by this process,
and those which have not lost their color greatly improved.
SKINNING, PRESERVING, AND SETTING UP REPTILES, AND MOLLUSCOUS ANIMALS,
ETC.