The notes of the Song-Sparrow would not entitle him to be ranked among our principal singing-birds, were it not for the remarkable variations of his song, in which respect he is equalled, I think, by no other bird.  Of these variations there are seven or eight which may be distinctly recognized, and differing enough to be considered separate tunes.  The bird does not warble these in regular succession; he is in the habit of repeating one several times, and then leaves it, and repeats another in a similar manner.  Mr. Paine[1] took note, on one occasion, of the number of times a Song-Sparrow sang each of the tunes, and the order of singing them.  Of the tunes, as he had numbered them, the bird “sang No. 1, 27 times; No. 2, 36 times; No. 3, 23 times; No. 4, 19 times; No. 5, 21 times; No. 6, 32 times; No. 7, 18 times.  Perhaps next he would sing No. 2, then perhaps No. 4, or 5, and so on.”  Mr. Paine adds, “Some males will sing each tune about fifty times, though seldom; some will only sing them from five to ten times.  But as far as I have observed, each male has his seven songs.  I have applied the rule to as many as a dozen different birds, and the result has been the same.”

An individual will sometimes, for half a day, confine himself almost entirely to a few of these variations; but he will commonly sing each one more or less in the course of the day.  I have observed also, that, when one principal singer takes up a particular tune, other birds in the vicinity will unite in the same.  The several variations are mostly in triple time, a few in common time, and there is an occasional blending of both in the same tune, which consists usually of four bars or strains, sometimes five, though the song is frequently broken off at the end of the third strain.  This habit of varying his notes through so many permutations, and the singularly fine intonations of many of them, entitle the Song-Sparrow to a very high rank as a singing-bird.

There is a manifest difference in the expression of these several tunes.  The one which I have marked as No. 3 is particularly plaintive, and is usually in common time.  No. 2 is the one which I think is most frequently sung.  No. 5 is querulous and entirely unmusical.  There is a remarkable precision in the song of this bird, and the finest singers are those which, in the language of musicians, have the least execution.  There are some individuals that blend their notes together so promiscuously, and use so many flourishes, that it is difficult to identify their song, or to perceive its expression.  Whether these tunes of the Song-Sparrow express to his mate, or to others of his species, different sentiments, and convey different messages, or whether the bird adopts them for his own amusement, I have not been able to determine.  Neither have I learned whether a certain hour of the day or a certain state of the weather predisposes him to sing a particular tune.  This point may, perhaps, be determined by some future