28
w.w.L. Au
emissions by baleen whales. A model of blue whale (B. mursculus) sound
production mechanism involving the larynx is presented in the chapter by
Aroyan et al. (Chapter 10). The vocalization of baleen whales can be
divided into two general categories: songs and calls (Clark 1990). The calls
can be further subdivided into three categories: simple calls, complex calls,
and clicks, pulses, knocks, and grunts (Clark 1990). Simple calls are often
low-frequency, frequency-modulated signals with narrow instantaneous
bandwidth that sound like moans if a recording is speeded up or slowed
down, depending on the specific animal. Amplitude modulation and the
presence of harmonics are usually part of a simple call, with most of the
energy below 1kHz. Complex calls are pulselike broadband signals with a
variable mixture of amplitude and/or frequency modulation. They sound
like screams, roars, and growls, with most of the energy between 500 and
5,000 Hz. Clicks, pulses, knocks, and grunts are short-duration «O.ls)
signals with little or no frequency modulation. Clicks and pulses are very
short «2ms) signals with frequencies between 3 and 31 kHz, while grunts
and knocks are longer (50 to lOOms) signals in the 100 to 1,000Hz range
(Clark 1990).
5.1 Songs of Mysticete Whales
Songs are defined as "sequences of notes occurring in a regular sequence
and patterned in time" (Clark 1990). Songs are easily discriminated from
calls in most instances. Four mysticete species have been reported to
produce songs; the blue whale, B. musculus (Alling et aI.1991), the fin whale,
Balaenoptera physalus (Watkins et al. 1987), the bowhead whale, B. mysticetus (Ljungblad et al. 1982), and the humpback whale, M. novangliae
(Payne and McVay 1971; Winn and Winn, 1978). Songs of humpback whales
have without a doubt received the most attention from researchers. Part
of the reason for this is the relative ease for investigators to travel and do
research in the summer grounds of humpback whales, especially Hawaii in
the Pacific and Puerto Rico in the Atlantic.
5.1.1 Humpback Whale Songs
A list of studies involving M. novangliae, humpback whale, songs is long
and extends from 1971 to the present time (Helweg et al. 1992). Some
general properties of songs and the whales that are singing are:
1. Songs from the north Pacific, south Pacific, and Atlantic populations are
different.
2. Singing peaks during the winter months when humpback whales migrate
to warmer waters at lower latitudes.
3. Whales within a population sing the same basic song in anyone year
although the song may undergo slight changes during a breeding
season.
w.w.L. Au
emissions by baleen whales. A model of blue whale (B. mursculus) sound
production mechanism involving the larynx is presented in the chapter by
Aroyan et al. (Chapter 10). The vocalization of baleen whales can be
divided into two general categories: songs and calls (Clark 1990). The calls
can be further subdivided into three categories: simple calls, complex calls,
and clicks, pulses, knocks, and grunts (Clark 1990). Simple calls are often
low-frequency, frequency-modulated signals with narrow instantaneous
bandwidth that sound like moans if a recording is speeded up or slowed
down, depending on the specific animal. Amplitude modulation and the
presence of harmonics are usually part of a simple call, with most of the
energy below 1kHz. Complex calls are pulselike broadband signals with a
variable mixture of amplitude and/or frequency modulation. They sound
like screams, roars, and growls, with most of the energy between 500 and
5,000 Hz. Clicks, pulses, knocks, and grunts are short-duration «O.ls)
signals with little or no frequency modulation. Clicks and pulses are very
short «2ms) signals with frequencies between 3 and 31 kHz, while grunts
and knocks are longer (50 to lOOms) signals in the 100 to 1,000Hz range
(Clark 1990).
5.1 Songs of Mysticete Whales
Songs are defined as "sequences of notes occurring in a regular sequence
and patterned in time" (Clark 1990). Songs are easily discriminated from
calls in most instances. Four mysticete species have been reported to
produce songs; the blue whale, B. musculus (Alling et aI.1991), the fin whale,
Balaenoptera physalus (Watkins et al. 1987), the bowhead whale, B. mysticetus (Ljungblad et al. 1982), and the humpback whale, M. novangliae
(Payne and McVay 1971; Winn and Winn, 1978). Songs of humpback whales
have without a doubt received the most attention from researchers. Part
of the reason for this is the relative ease for investigators to travel and do
research in the summer grounds of humpback whales, especially Hawaii in
the Pacific and Puerto Rico in the Atlantic.
5.1.1 Humpback Whale Songs
A list of studies involving M. novangliae, humpback whale, songs is long
and extends from 1971 to the present time (Helweg et al. 1992). Some
general properties of songs and the whales that are singing are:
1. Songs from the north Pacific, south Pacific, and Atlantic populations are
different.
2. Singing peaks during the winter months when humpback whales migrate
to warmer waters at lower latitudes.
3. Whales within a population sing the same basic song in anyone year
although the song may undergo slight changes during a breeding
season.