Biology Reference
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Fig. 7.4
Spring (
open circles
) and autumn (
black circles
): number of songs broadcast by males of
winter wren (
Troglodytes troglodytes
) before and after playback of mating male intrusion at dawn
(Reproduced with permission from Erne and Amrhein
2008
)
work demonstrates the importance in territory defense of the acoustic communica-
tion in those two periods. Playback experiments conducted after sunrise and before
sunset have not found a significant difference in song output.
Morse (
1989
) discussed the role of song patterns of northern parula (
Parula
americana
), magnolia warbler (
Dendroica magnolia
), yellow-rumped warbler
(
D. coronata
), black-throated green warbler (
D. virens
), and the blackburnian
(
D. fusca
) warbler at dawn and dusk, represented by unaccented ending song as
an advertisement display utilized by males that are singing well spaced, and with
females not in evidence, as a communication tool to advertise of presence of singers
to eventual intruders.
7.6 Reproduction Mechanisms and Choruses
In some species song activity at dawn is coincident with the fecundity period of
females. Song is a phenotypic character that is connected with sexual selection, and
we can expect that a complex song, louder and repeated for a long time, represents a
honest signal in mate selection.
In the great tit (
Parus major
) and in the blue tit (
Cyanistes caeruleus
), males
repeat a particular song type for some time, then they adopt another song type. This
phenomenon has been called “drift” and could be dependent on neuromuscular
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