Reproduction and Migration.
The continuation of the species is carried on by eggs, which are laid in a nest more or less artificial according as the nestling is more or less capable of gathering its own food at the time of its exclusion from the egg. Of those birds whose young possess this capability in the highest degree, the male is for the most part polygamous, and does not pair; but among those whose young depend for some time on the parents for their sustenance, one male confines his attentions to one female, as long at least as the seasons of love, incubation, and parental anxiety endure. To the first and second of these seasons we, in great measure, owe that outpouring of melody which renders our groves and gardens so musical in spring.
" There is every reason," writes Montagu, " to believe it is necessary there should be native notes peculiar to each species, or the sexes might have some difficulty in discovering each other, the species be intermixed, and a variety of mules produced ; for we cannot suppose birds discriminate colours by which they know their species, because some distinct species are so exactly alike that a mixture might take place. The males of song-birds, and many others, do not in general search for the female ; but, on the contrary, their business in the spring is to perch on some conspicuous spot, breathing out their full and amorous notes, which by instinct the female knows, and repairs to the spot to choose her mate. This is particularly verified with respect to the summer birds of passage. The nightingale and most of its genus, although timid and shy to a great degree, mount aloft to pour forth their amorous strains incessantly, each seemingly tieing in their love-laboured song before the females arrive. No sooner do they make their appearance than dreadful battles ensue, and their notes are considerably changed ; sometimes their song is hurried through without the usual grace and elegance, at other times modulated into a soothing melody. The first we conceive to be a provocation to battle on the sight of another male ; the last an amorous cadence, a courting address. This variety of song lasts no longer than till the
female is fixed in her choice, which is in general in a few days after her arrival ; and if the season is favourable she soon begins the task allotted to her sex." We entirely agree with the writer of this animated passage that "'Tis love creates their melody," and that the car is a principal guide to the hen-bird in her choice of a mate ; but we cannot entirely exclude the eye when we remember what pains have been taken In most in stances to distinguish the sexes by the colour of their feathered garb, and even in many instances to prepare a nuptial dress ('plumage de nOcea ' of the French) for the male, which fades when the season of love has passed away.
We must not dwell here upon the wonders of birds'-nests, their admirable structure as places of comfort and concealment, and the exquisite workmanship of some of them—that of the goldfinch, for instance. In those snug receptacles the eggs are deposited and hatched. Then the old birds feel all the parent within them, and entirely forget their own safety and wants in protecting and providing for their help less nestlings. This parental love changes the timid at once to tho brave ; for birds of prey, cats, dogs, and sometimes even man, when be approaches the sanctuary, are attacked and followed with angry cries. For some time after quitting the nest this care continues, till the nestling is able to provide for itself. Then the whole seeno changes. The young bird still lingers about the old one, and approaches it when it finds a worm or insect, expectant of the morsel. At first the young bird is unheeded and treated coldly ; but if it does not take this hint, and perseveres in its solicitations, the parent, which but a few days before would have braved a hawk or a eat in its defence, and would have been content to suffer hunger rather than have seen it without food, gives it a buffet, and thus compels it to rely on its own resources.