I've termed flock calls those calls that are made between birds as they forage (that are not flight or aggressive calls). Chase and other agonistic calls are calls between two or more birds, involving chasing or other apparently aggressive behavior.
Dark-eyed Junco, a flock of about 60 birds at Whitesbogs, NJ in November. The predominant call is the tu-tu flock call, other calls are the buzzy flight call, one bird singing at 6s and a titter call at 10s.
buzzy flight calls and titter call (above tu-tu calls)
Another example of the tu-tu calls with a series of rapid chips at the end of the recording (Dec, PA).
Flock calls of White-throated Sparrows include chip calls and "laughing" calls (Oct, NJ).
laughing calls (Dec, PA)
When White-throated Sparrows interact closely, they chip rapidly. So it appears that the chip call is used for flock communication, aggressive interaction and as an alarm call.
Two birds rising in the air in a brief aggressive encounter at 4s, with flight calls (Dec, NJ).
American Tree Sparrows are also very vocal in winter. This is their common call, a unique "chu-wit".
single bird (Jan, PA)
flock (Jan, PA)
single bird (Dec, PA)
flock (Dec, PA)
These are also termed growls.
Savannah Sparrow (Oct, PA).
Swamp Sparrow interaction calls are lower (at dusk, Nov, PA)
chips followed by growls
Chipping Sparrow (Nov, PA).
Song Sparrow excited chip series, presumed interaction between two birds (dusk, Nov, PA). This may be the previously described chitter call.
the full series, reduced time scale
American Tree Sparrow growl (Jan, PA).
American Tree Sparrow or Song Sparrow growl. Note: heard among a group of American Tree Sparrows, Song Sparrow also present, but the calling birds were not observed:
Other agonistic calls
This low grating call was made by a Song Sparrow while feeding with White-throated Sparrows and Dark-eyed Juncos, and appeared to be an aggressive vocalization. It was not made when the bird was feeding alone (Dec, PA).
This call was made during an aggressive interaction between a White-throated and Song Sparrow, where the Song Sparrow was the aggressor (identity of calling bird unknown,Jan, PA).
Various twittering calls (calls above 6kHz) by male Field Sparrow before dawn (May, DE).
Twittering between two Field Sparrows (May, DE).
Interaction calls between an Eastern Towhee (male) and Spotted Towhee (female) where the Eastern Towhee was the aggressor. One bird is uttering a series of chips, followed by two buzzy calls from the other bird. The series of chips has been described in the literature as a fear or flee call and is made by both species (Dec, Palmyra, NJ).
Chipping Sparrow calls while mating, a rapid series of chips at 8 and 21s (May, DE).