"The songs of other birds, the sounds of instruments, the tones of a sweet sonorous voice, excite them much. They run, they approach, attracted by the sweet sounds; but duets attract them still more powerfully, which would seem to prove that they are sensible to the effects of harmony. They do not continue silent auditors, they join the performance, and use all their efforts to eclipse their rivals, to surpass all the other voices, and even all other sounds. It is said that they have been known to drop down dead at the feet of a person singing. Another has been seen fluttering, swelling his throat, and uttering an angry warble every time a canary which was near him, began to sing; he succeeded by his threats in imposing silence, so true is it, that superiority is not always free from jealousy. Can it be in consequence of the passion for pre-eminence, that these birds are so careful to seize every advantage, and that they prefer singing in a place favourable to sound, or within reach of an echo? "All nightingales do not sing equally well. Some are so very inferior as not to be worth keeping. It has even been thought that the song of the nightingale is different in different countries. In England, those who are curious respecting these birds, prefer, it is said, those of the county of Surrey, to those of Middlesex; as they prefer the greenfinch of Essex, and the goldfinch of Kent. This diversity of song among birds of the same species has very rationally been compared to the different dialects of the same language. The true causes can hardly be assigned, as they are for the most part accidental. A nightingale may perhaps have heard other singing birds, or emulation may have caused him to perfect his song, which he thus transmits improved to his descendants, for every father is the singing master of his family; and it is easy to perceive that in succeeding generations the song may be still further improved or modified by similar accidents. "After the month of June, the nightingale sings no more, and he retains only a hoarse cry, a sort of croaking, by which the melodious Philomel cannot be recognised, and it is not surprising that formerly, in Italy, they gave him a different name under these circumstances. He is indeed another bird, a bird altogether different in respect of voice, and even, in a great degree, in respect of the colour of his plumage.