Thursday, January 13

Warbler songs I

Several warbler species sing two different types of song, known as accented and unaccented. Accented songs are sung to attract females, unaccented songs are considered to have a more aggressive function and are used to maintain territory. Accented songs are sung all day until the male is paired up, and then singing drops off significantly. Unaccented songs are the predominant songs given at dawn and dusk.

In "The Singing Life of Birds" by Don Kroodsma we learn that the male Chestnut-sided Warbler learns accented songs (there are 4-5) in the first year of life, probably in migration. These songs are the same throughout the species' range. The unaccented song is not learnt until the young male arrives on his breeding grounds, and is learnt from neighboring males. Each male learns up to 12 unaccented songs. Each local group of Chestnut-sided Warblers has a different set of unaccented songs, so that throughout the species' range the number of variations is innumerable.

Chestnut-sided Warbler, accented song (July, ME)

unaccented song (July, ME)

The American Redstart has a repertoire of 1-4 accented and 2-10 unaccented songs (up to 12 total). Accented songs end in a chevron on the sonagram. Individual accented songs tend to be repeated over and over (repeat mode) whereas the unaccented are often sung in variable sequences (serial mode).
accented in repeat mode(May, NJ)

unaccented in serial mode, actually two phrases alternating (July, ME)

Songs in serial mode (May, NJ).

The Black-throated Blue Warbler is another species that has two different song types. The so-called Type 1 song has several relatively pure-toned notes in the beginning. The Type 2 song usually has less notes, all buzzy. It is likely one is used for maintaining territory, and the other for attracting females, but not a lot of study has been done on this species.
Type 1 (July, ME, juvs in background)

Type 2 (July, ME)

Prairie Warblers sing several versions of two song types, called A and B, which are equivalent to accented and unaccented respectively.
Type A is a rising series of buzzy notes (June, NJ).

Type B begins with clear notes (June, NJ).

Each Hooded Warbler sings one accented but several non-accented songs.
accented (May, NJ)

unaccented (May, NJ)

The Blackburnian Warbler has these two song types, but each male usually sings only one version of each (this is the more common situation in the warblers):
accented (July, ME)

unaccented (July, ME)

Individual males of the next few species also sing only two different songs, one of each type, accented and unaccented.

Magnolia Warbler.
accented (July, ME)

unaccented (July, ME)

Northern Parula.
Type A or accented, a simple rising buzz with an end note (migrant, May, PA)

Type B or unaccented, more complex with clear and buzzy notes (July, ME)

Black-throated Green Warbler.
accented song (July, ME)

unaccented (July, ME)

Cerulean Warbler.
accented (June, NJ)

Blue-winged Warbler (with Common Yellowthroat)
accented (May, NJ)

Tennessee Warblers sing either a 2-parted or a 3-parted song, the different song-types are of unknown significance.
3-parted(migrant, May, ND)

Another 3-parted song (migrant, May, ND)

Nashville Warblers sing a faster song at dawn that may function as an unaccented song. The regular slower version of the song is sung during the day and in interactions with females (Birds of North America).
regular song(July, ME)

Blackpoll warblers have two different song types (per BNA), delivered at different speeds, which may function as accented or unaccented songs. There has been speculation that song speed varies geographically. The following are recordings of migrants.
(May, PA)

faster song (May, PA)

Even faster song (May, PA)

Pine Warblers have a repertoire of more than one song and some songs are faster than others.
(June, NJ)

rapid song (June, NJ)

Pine Warbler singing 15 minutes before sunrise, running through an apparent repertoire of four songs (June, NJ). Incidentally, this is a good way to distinguish a singing Pine Warbler from the similar Chipping Sparrow and Worm-eating Warbler, as those birds sing only one song.

The Black-and-white Warbler has a "squeaky wheel" song, but there is another version that is more extended.
regular song (May, NJ)

This example lacks the more usual up and down arrangement of notes (May, NJ)

extended version (June, NJ)

Each Canada Warbler sings about 11 different songs, often given in serial mode. A flight song has also been described.
(migrant, May, NJ)

Yellow-rumped Warblers have a variety of song phrases, as shown by this migrant singing in serial mode ie different consecutive phrases.
(May, NJ)

1st phrase

2nd phrase

3rd phrase

4th phrase

According to BNA, Yellow Warblers have a repertoire of about 15 songs, which may be accented or unaccented, but it is the mode of singing that defines song classification, independent of whether or not the song is accented, with more immediate variety at dawn, and repeat mode predominating during the day.
This bird was recorded at dawn (May, NJ).

phrases 1 and 2

phrases 3-6

phrases 7 and 8

phrase 9

The Yellow-breasted Chat has a highly variable song including mimicry, in this case crow calls (June, NJ)

No comments: