With the female Illinois parrot (_Psittacus pertinax_) widowhood and death are synonymous, a circumstance rare enough in the human species, yet of which birds give us more than one example. When, after some years of conjugal life, a wheatear happens to die, his companion hardly survives him a month. The male and female of the _panurus_ are always perched side by side. When they fall asleep, one of them, generally the male, tenderly spreads its wing over the other. The death of one, says Brehm, is fatal to its companion. The couples of golden wood-peckers, of doves, etc., live in a perfect union, and in case of widowhood experience a violent and lasting grief. The male of a climbing wood-pecker, having seen his mate die, tapped day and night with his beak to recall the absent one; then at length, discouraged and hopeless, he became silent, but never recovered his gaiety (Brehm). These examples of a fidelity that stands every test, and of the religion of memory, although much more frequent in the unions of birds than in those of human beings, are not, however, the unfailing rule. With birds, as with men, there seems to be a good number of irregular cases--individuals of imperfect moral development and of fickle disposition. This may be inferred from the facility with which, among certain species of monogamous birds, the dead partner is replaced. Jenner, who introduced vaccination, relates that in Wiltshire he has seen one of a couple of magpies killed seven days in succession, and seven times over immediately replaced. Analogous facts have been observed of jays, falcons, and starlings. Now, when it concerns animals that are paired, each substitution must correspond to a desertion, the more so as the observations were made in the same locality and in the height of the breeding season.[44] Very peculiar fancies sometimes arise in the brains of certain birds. Thus we see birds of distinct species pairing, and this even in a wild state. These illegitimate unions have been observed between geese and barnacle geese, and between black grouse and pheasants.