"The second form begins in the same manner, but has all the notes of equal time, and the last three or four successively lower in pitch. I have records of 24 such songs. There remain in my records 18 songs so variable that they belong to neither of these forms, and yet no two of them are similar in form. A number of songs of the different forms begin with slurred notes, the slurs being about equally up or down in pitch. "Songs vary from 1-1/5 to 2 seconds in length, averaging about 1-2/5 seconds. The pitch varies from A´´´´ to D´´´´´, only three and a half tones altogether. Single songs vary from one to two and a half tones in range of pitch, averaging about one and a half tones. Individual birds may sing as many as three different songs, and sometimes sing two different songs in regular alternation. "Singing continues from the first arrival in migration until the third week of July, ceases for a short time, but is usually revived in August, and is to be heard irregularly until the birds depart for the south." Francis H. Allen gives me his impressions of the two common songs as follows: "One of these I have been accustomed to render as _wee see wee see wiss wiss´-u_. Occasionally the final _wiss´-u_ is doubled. The other of these two songs goes something like _wee wee wee witita weet_, without the drop in the pitch that the first song has at the final note. I have also heard a song of five single notes with no variation in pitch or tempo--_weet weet weet weet weet_. Besides a rather sharp _chip_, which is the ordinary call-note, I have heard a _dzee_ from a yellow warbler." The yellow warbler is an early riser. Mr. Smith (1943) heard one begin singing at 4:56 a.m., "daylight time," and another at 4:05, "but with only one song until 4:08 when seven were given during the space of one minute. During the song period of fifty minutes, 197 songs were given." Dr. Charles W. Townsend told Mr. Allen that he heard one at Ipswich, Mass., on June 13, 1908, that began singing at 3:10 a.m., but this was standard time. Dr. Winsor M. Tyler (1937) mentions a peculiar note, heard during the migration in August, which had puzzled him for nearly 30 years until he finally traced it to an eastern yellow warbler. "As we walk under the trees, listening, we hear a long, wild, high, sharp bird-note, abrupt, and very slightly vibratory, lasting perhaps half a second. It is a characteristic sound of this time of year, and we hear it best on these quiet, silent days. It comes from a bird moving restlessly up in the trees, and before we can see the bird, it is gone. * * * In pitch, it suggests the call of a migrating Ovenbird, but it is too long-drawn-out; it suggests the _chip_ of a Northern Water-Thrush in its sharp abruptness, but again it is too long."