Characteristics and Significance of Song in Female Oriental Magpie robin, Copsychus Saularis

5 Pages·2002·2.6 MB·

by  Anil Kumar

,
CHARACTERISTICS AND SIGNIFICANCE OF SONG
IN FEMALE ORIENTAL MAGPIE-ROBIN, COPSYCHUS SA ULARIS1
Anil Kumar2 3 and Dinesh Bhatt2
’
(With one text-figure)
Key words: Copsychus saularis, song of female, communication,
territorial defence, spectrograms
Singing behaviour of the female Oriental magpie-robin, Copsychus saularis was studied. The
female sings occasionally for a short period in the presence of the male. The song consists of
phrases made up of different elements. The minimum, maximum and range offrequencies were
found to be 2.42 ±0.03, 5.03 ±0.08 and 2.61 ±0.02 kHz, respectively while the duration of the
phrases were 1.38 ±0.02 sec, followed by an interval of 1 .49 ±0.03 sec. It appears that the female
magpie-robin’s song helps to stimulate the male to sing.
Introduction Methodology
Bird song performs a variety of functions The Oriental magpie-robin breeds during
(Ali 1996). In most passerine species, song is March to August in northern India (Ali 1996,
the characteristic of the male and is used for Roberts 1992, Kumar 1999). Songs of five
territorial defence through advertisement and females were recorded from March 1997 to
mate acquisition (Cooney and Cockburn 1995, August 1998, at Haridwar (29° 55’ N, 78° 8’ E),
Bhatt et al. 2000). Besides these two functions, using a JVC Zoom MZ-500 unidirectional
birds also use the song to synchronize breeding microphone and a SONY CFS 1030S tape
behaviour, mate guarding, mate recognition, recorder. Most signals were recorded at a
parent-offspring recognition and neighbour- distance of 2-5 m. Pre- and post-signalling
stranger discrimination (Weary et al. 1992, behaviour and circumstances in which
Lambrechts and Dhondt 1995). The song in the signalling occur were observed to infer the
female has also been studied in many passerine meaning of the song. After editing, cuts of
species. In some species it is rare, while in others high quality recordings (a few seconds duration)
the females normally sing duets with males were used for physical analysis (charac-
(Ridgely and Tudor 1989). The major functions teristics based on frequency and duration).
of the song of the female include territorial In the present study, we used minimum
defence, prevention of polygyny and intra-pair frequency, maximum frequency, range of
communication (Flood 1990). frequencies, duration of phrases and interval
In the present study, an attempt has been between phrases, to define the physical
made to investigate physical characteristics and characteristics of the songs. The analysis was
functional significance ofthe song in the female made with the help of Scientific 25 MHz
Oriental magpie-robin, Copsychus saularis. Digital Storage Oscilloscope HM205-3,
interfaced with a PC (Pentium) and signal
'AcceptedNovember, 2001
departmentofZoologyandEnvironmental Science, analyzer software SP 91 (Bhatt et al. 2000).
Gurukul Kangri University, Haridwar249404, Spectrograms were generated with the help of
Uttaranchal, India. DSP Sonagraph™ 5500 machine using
Presentaddress: WildlifeInstituteofIndia,
Post BoxNo. 18, Chandrabani, DehraDun 248 001 SIGNAL™, a software package for sound
Uttaranchal, India. generation and analysis.
54 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 99(1), APR. 2002
1
SONGINFEMALEORIENTALMAGPIE-ROBIN
Results mating. It appears that the function ofthe female
song in magpie-robin is to stimulate the male
The female Oriental magpie-robin for (i) initiation of breeding activities (i.e.
occasionally sings a short, low amplitude song formation of breeding territory), and (ii)
in the presence ofthe male. In most cases (n=7), courtship.
they were observed singing alone. However, male
and female were once seen singing a duet at a Discussion
distance ofabout 25 cm. The female song consists
of phrases, either similar (repetition of same Our results reveal that the female
phrase) or dissimilar in structure as observed in Copsychus saularis sings rarely, and uses almost
male birds. Minimum, maximum and range of same frequencies as male birds. However, the
frequencies were found to be 2.42 ±0.03, 5.03 maximum frequency, range of frequencies and
±0.08 and 2.61 ±0.02 kHz respectively, while the relative amplitude was found to be higher in
duration ofphrases was 1.38 ±0.02 sec followed males (Table 1). The female rarely sings. It seems
by an 1.49±0.03 sec interval (Fig. 1). Since the that the biological significance of the female’s
female sings rarely, only a few song samples song is restricted to initiating the males to sing,
could be recorded and the analysis is restricted while in males the song is common during
to a few select phrases. Analysis of the data breeding and is used for territorial defence and
reveals that the female uses almost the same mate acquisition (Bhatt et al. 2000).
frequency pattern as the male birds do (Table 1). In many species of birds and mammals,
Interestingly, the female started singing before both the sexes live together throughout the year
the male. Thus, it appears that in C. saularis but courtship takes place when a female gives
,
onset of breeding is indicated by female song. signs ofreadiness in the form ofolfactory/vocal/
However, in some males (n=4), the singing was visual cue(s). In the magpie-robin group, females
initiated on listening to the song ofneighbouring normally use singing for this purpose. In the
males. In two cases, the female was found singing polygynous redwinged blackbird-, Agelaius
at the time of the second brood, just before the phoeniceus of North America, Beletsky (1983)
Table
1
COMPARATIVE ACCOUNTOF THE PHYSICALAND ASSOCIATED CHARACTERISTICS OF SONG
OF MALE AND FEMALE, ORIENTAL MAGPIE-ROBIN COPSYCHUSSAULARIS
S. No. Characteristics Female Male
(Bhattetal. 2000)
1. Numberofindividuals(N), studied 5 14
2. Numberofsamples(n), taken forstatistical analysis (mean±SE) 12 84
3. Minimum frequency(kHz) 2.42 ±0.03 2.39±0.04
4. Maximumfrequency(kHz) 5.03 ±0.08 5.41 ±0.07
5. P.angeoffrequency(kHz) 2.61 ±0.02 3.19±0. 1
6. Durationofphrases(sec) 1.38 ±0.02 1.52±0.05
7. Interval between phrases (sec) 1.49±0.03 1.09±0.04
8. Relative amplitude Low High
9. Useofsong Rare Common inbreedingseason
10. Conspecificcontext Alwaysobserved in Irrespectiveofthe presence/
thepresenceofmale absenceoffemale
11. Biological function Probably initiatethe Forterritory advertisement
malestosing andmateacquisition
JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 99(1), APR. 2002 55
SONGINFEMALEORIENTALMAGPIE-ROBIN
characteristics,
phrases.
physical
between
different interval
the and
phrases
showing
of
saularis
duration
Copsychus
frequency,
of
magpie-robin
range
Oriental frequency,
female
minimum
the
of
frequency,
song
the
of
maximum
Spectrogram
namely
1:
—
i — i— 1 ”^i «r "« - - — b o Fig.
h. to U) CM r-
Aouanbajj
(ZHM)
56 JOURNAL BOMBAY NATURAL HISTORY SOCIETY, 99(1), APR 2002
,
SONGINFEMALEORIENTALMAGPIE-ROBIN
found two types of female song with varied The song of the Northern cardinal seemed to
functions. These songs probably help in stimulate the males to join in and sing as well. It
communication between the mated pair and are is suggested that female song in cardinals might
aggressive signals. As in the Oriental magpie- function in pair bonding or synchronising
robin, the song of the female European robin, reproductive physiology (Ritchison 1986, Moller
Erithacus rubecula is shorter and simpler than 1991).
the male song (Lack 1946). Female white- The present study indicates that the
crowned sparrow, Zonotrichia leucophrys also magpie-robin is a good model to study the
produce a song, which is structurally similar to functional significance of song of female birds.
that of the male, but usually shorter in duration It provides basic information on the song of the
A
(Baptista et al. 1993). female magpie-robin. detailed study is required
In the European robin, Erithacus rubecula to know the repertoire of female song and its
the female song is clearly related to the winter functional significance.
territorial behaviour (Hoelzel 1986), while in
Oriental magpie-robin the female generally does Acknowledgments
not exhibit territorial behaviour. However, during
We
breeding if a predator appears in the territory, thank Dr. A.K. Chopra, Head, Dept,
the female helps the male to chase it away, both ofZoology and Environmental Sciences, Gurukul
producing threat calls. The female was never Kangri University, Haridwar, for facilities,
observed chasing conspecifics during this study. Dr. Sandra L. L. Gaunt and Dr. Hitesh Khanna,
In Northern cardinals, Richrnondena cardinalis, Department of Zoology, Ohio State University,
USA We
Ritchison (1986) found that females sang during for the preparation ofspectrograms. are
a particular phase of the breeding cycle, just thankful to Dr. Q.H. Baqri, Officer-in-Charge,
before nesting, and there was no evidence from Desert Regional Station, Zoological Survey of
field observations or playback experiments that India, Jodhpur, for his valuable comments.
female song helped to establish or defend Financial assistance from DST (Govt, of India)
territory, just as in the Oriental magpie-robin. is also gratefully acknowledged.
Refer
N C E S
Ali, S. (1996): The Book of Indian Birds, 12"' edition. to playbackofmale and femalerobins, Erithacus
BombayNatural History Society, Mumbai. rubecula. Ibis 128: 115-127.
Baptista, L.F., P.W. Trail, B.B. DeWolfe & M.L Morton Kumar, A. (1999): Characteristics and significance of
(1993): Singing and its functions in female white- calls, songs and visual displays in two avian
crowned sparrows. Anim. Behav. 46: 51 1-524. species viz. Copsychus saularis and Pycnonotus
Beletsky, L.D. (1983): Aggressive and pair bond cafer. Ph.D. thesis. Gurukul Kangri University,
maintenance songsoffemalered-winged blackbirds Haridwar.
(Agelaiusphoeniceus). Z. Tierpsychol. 62: 47-54. Lack, D. (1946): The lifeofthe Robin. London: Witherby.
Bhatt, D., A. Kumar, Y. Singh & R.B. Payne (2000): Lambrechts, M.M. & A.A. Dhondt 995): Individuals
(1
Territorial songs and calls inoriental magpie-robin, voice discrimination in birds. In: Current
Copsychus saularis. Curr. Sci. 78(6): 722-728. Ornithology(Ed.: Power, D.M.). Vol. 12: 115-139,
Cooney, R. & A. Cockburn (1995): Territorial defence is Plenum Press, New York.
the major function of female song in the superb Moller, A.P. (1991): Whymatedsongbirds singso much,
fairy-wren Malurus cyaneus). Anim. Behav. 49: mate guarding and male announcement of mate
(
1635-1647. fertility status. Amer. Nat. 138: 994-1014.
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Audubon’s oriole. J. FieldOrnithol. 61: 290-302. America, Vol. /: UniversityofTexas Press, Austin,
Hoelzel, A.R. (1986): Song characteristics and response Texas.
JOURNAL, BOMBAY NATURAL HISTORY SOCIETY 99(1), APR. 2002 57
SONGINFEMALEORIENTALMAGPIE-ROBIN
Ritchison, G. (1986): The singing behaviour of female UniversityPress, Karachi, Pakistan.
northern cardinals. Condor 88: 156-159. Weary, D.M., R.E. Lemon & S. Perrault (1992): Song
Roberts, T.J. (1992): The Birds of Pakistan (Vol. 2), repertoire do not hinder neighbour-stranger
Passeriformes: Pittas to Buntings. Oxford discrimination. Behav. Ecol. Socibiol. 31: 441-447.
58 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 99(1), APR. 2002