The Carolina Chickadee sings a usually four-part song, but there may be from three to five notes in each phrase. The following songs were all by the same bird at dawn, when it went through its repertoire, including gargle-type songs (the gargle is more often used as a call note).
four-part song(Apr, PA)
three and five-part song
four-part song followed by gargled variations
For more on the gargle song go to Carolina Chickadee gargle song.
The Black-capped Chickadee has a two-parted song that uniquely remains unchanged across most of its range ie with a few exceptions there is an absence of dialects.
The birds vary the song with frequency changes, as at 42s in this recording (May, RI). Note the short note before each phrase.
Tufted Titmice each have a repertoire of up to ten songs. Here are several examples:
A nice example of matched counter-singing (June, NJ).
Four males in close proximity counter-singing (Mar, PA)
Two males countersinging, but the songs do not match and often overlap. As the songs show some variability it suggests to me that these may be young birds. When adult birds sing over a neighbor it is a sign of increased aggression, but in this case it could just be two neighboring birds practicing their songs. Or perhaps they have not yet learned to correctly countersing ie the birds have to learn not only their songs but also the way they use them in relation to their neighbors.
Odd vocalizations heard in spring often turn out to be a Tufted Titmouse (May, NJ).
A two-parted song with high and trilled syllables (Mar, PA)
A trill-like song by a Tufted Titmouse pursuing another through bushes, with a non-participating third bird in attendance (Mar, PA).
A bird singing and another replying with a call-like song, either two males or a pair (Mar, PA)
Another example of two birds answering each other in song-like fashion, even though the vocalizations sound like calls (Mar, PA).
Another example of a high vocalization made repetitively in a song-like fashion. In the family Paridae the distinction between calls and songs is often ill-defined (Apr, PA).