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Why might it be important to learn more
about loon music?
Jay Mager Department of Biological & Allied Health Sciences Ohio Northern University Ada, Ohio 45810 [email protected]
Charles Walcott Department of Neurobiology & Behavior Cornell University Ithaca, New York 14853 [email protected]
A
B Benefit
Net Benefit A = 100
Net Benefit B = 70
?
A
B
Benefit Cost
Net Benefit A = 100 - 80 = 20
Net Benefit B = 70 - 20 = 50
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X
?
Dan Salsbury
W. Piper
Nathan Banfield
Yodel Acoustic Structure:
The yodel as an aggressive threat signal:
Given by only male Great Northern Divers (Gavia immer)
Given primarily to conspecific flyovers & intrusions
Given when probability of physical confrontation is high, & given in “vulture posture” during close confrontations
Given most frequently upon return to breeding territories & when chicks are about to hatch
Dan Salsbury
Yodel Acoustic Structure: Fighting Ability
(Mager et al. 2007, in prep)
FEINTRO3
1,650
1,700
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2,000
3900 4100 4300 4500 4700 4900 5100
Body Mass (g)
Peak
Fre
qu
en
cy (
kHz)
FEI
NTR
O3
y = -1.661x + 2.535; r2 = 0.470; P < 0.0001
Dominant frequencies of yodels are related to male body mass
Mager, et al. 2007
Pairs respond differently to yodels of lower frequency
Friedman’s χ2 = 10.20 ; N = 42; P = 0.0061 Friedman’s χ2 = 12.78 N = 42; P = 0.0017
Mager, et al. 2007
Not Land
Land
Res
po
nse
Non-resident FEINTRO3 Peak Frequency (kHz)
Intruders land to high-frequency non-resident yodels?
Logistic Likelihood Ratio χ2 = 5.985; N =33; P = 0.0144
0,0
1,0
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Peak Frequency (kHz) FEINTRO3
# R
epe
at S
ylla
ble
s /
Yod
el
y = -8.489x – 11.520; r2 = 0.142; P = 0.0077
High-frequency yodelers give more repeat phrases per yodel
Yodel Acoustic Structure: Aggressive “Motivation”
(Barklow 1979, Mager et al. 2012, in prep)
# REPEAT PHRASES
Variability in # repeat phrases: Longer yodels = heightened aggressive state
Males give more repeat phrases when risk of attack is greater
Repeated-measures ANOVA F4,216 = 6.207; P < 0.0001; N = 44 males
0,0
1,0
2,0
3,0
4,0
5,0
6,0
Flyover Distant Intruder Close Intruder Social Gathering Chase/Fight
Nu
mb
er
of R
ep
ea
t P
hra
se
s/Y
od
el
Mager, et al. 2012
Did the duration of yodels change after
adding platforms?
3
3.25
3.5
3.75M
ean
Nu
mb
er o
f R
epea
t P
hra
ses
2002 2003
Year
*
* Repeated-measures ANOVA F1,18 = 4.491, P = 0.048
Mager et al. 2010
Information communicated by yodel:
Dominant frequencies communicate body mass/condition
# repeat syllables communicate aggressive “motivation”
Do males of poorer condition compensate by being more “motivated”?
What factors ensure signal reliability, or “honesty”?
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Yodel Acoustic Structure: Individual Identity (Walcott et al. 1999, 2006; Lindsay 2000)
FINTRO3
DGA
P DINTRO
FINTRO1U F2RPT1B F1RPT1A
D1RPT1B
DGAP2
Why would individual recognition be important for divers?
Recognition of territorial threats: •Male recognition of territorial rivals (Mager et al. 2010)
•Female recognition of mates (Mager & Walcott, in press)
Recognition of kin: •Chick recognition of fathers from threats •Male/female future recognition of sons, fathers, grandfathers, grandsons, etc.
Resident Males respond more
aggressively to non-neighbor yodels
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
Neighbor Non-neighbor
# Y
od
els
/ 1
0 m
in a
fter
Pla
yback
*
*Wilcoxon Z = 2.6, N = 20, P = 0.01 (Mager, et al. 2010)
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Diver communication “networks”
Great Northern Divers change their
yodels when they change territories (Walcott et al. 2006)
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Network consists of eavesdroppers
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Wayne Albertson
0,8
0,9
1
1,1
1,2
1,3
1,4
0,8 1 1,2 1,4
Son D
ura
tion (
sec)
Father Duration (sec)
Possible relationship between duration
components of repeat phrases
Slope = 0.312, df = 19, P = 0.025
Granddad
Dad
Son/Grandson
Value of learning more:
Diver Conservation & Management:
Acoustic signals are important to habitat selection & defense
Acoustic signals reflect individual condition & resource value
Vocal Signaling within a Non-Oscine Bird:
Acoustic signals within acoustic “networks” & “neighborhoods”
Acoustic signals within a long-lived species with natal fidelity
http://www.iyufera.com/data/photos/920_1pacific_loon_call_2.jpg
THANK YOU!!!!
Dr. Andre Dhondt, Dr. H. Kern Reeve, and Dr. Sandra Vehrencamp, Cornell
University, Dr. Walter Piper, Dr. David Evers, Dr. Mark Pokras, Dr. Amy
McMillan, Dr. James Paruk, Dr. Alec Lindsay, Dr. Judith McIntyre
Numerous Field Assistants: N. Banfield, M. Gibbon, R. Hart, B. Lampe, D.
Reid, M. Schwabenlander, A. Webber, A. & J. Reiman, F. Spilker, E.
Harrington, C. Ritchie, V. Abernathy, D. Salsbury, J. Backus, E. Nebgen, D.
Woods, K. Trinkle, K. Klotz
Supporting Agencies: M. Meyer & R. Eckstein, WDNR, Loon Preservation
Committee
Financial Support: Cornell Lab of O. W. E. Benning Fellowship, Kieckhefer
Adirondack Fellowship, M. B. Sussman Fellowship, Sigurd T. Olson Loon
Research Award, Sigma Xi Grants in Aid of Research, National Science
Foundation, Cornell University Dept. of Neurobiolgy and Behavior Research
Award, Ohio Northern University Faculty Research Grant
? ? ?
Pe
ak
Fre
qu
en
cy
Sylla
ble
2 R
pt
Ph
ras
e 2
(k
Hz)
Individuals
Sons produce higher frequency yodels
*
Paired t = 2.388, df = 19, P = 0.0137
Yo
del D
ura
tio
n (
seco
nd
s)
Group
Sons tend to produce longer yodels
*
Paired t = 1.901, df = 19, P = 0.0367
What is Communication?
Sender Receiver Information
Decision & Response
MESSAGE
MEANING
Smith, W.J. (1965)
0.00
0.05
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0.15
Ag
gre
ssiv
e E
nco
un
ters
2002 2003 2004
Year
0
0.1
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'So
cial
Gat
her
ing
s'
2002 2003 2004
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Ap
pro
ach
es
2002 2003 2004
Year
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Intr
usi
on
s
2002 2003 2004
Year
Did contests escalate on treatment territories?
*
*
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0.2
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0.8
# C
hic
ks
Hat
ched
/ E
gg
Lai
d
2002 2003 2004
Year
0
0.2
0.4
0.6
0.8
# C
hic
ks
Fle
dged
/ E
gg L
aid
2002 2003 2004
Year
Platform territories experienced lower
reproductive success during the treatment year.
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*signficant at an of 0.05 (Mann-Whitney Z test)
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Pairs tremolo more to yodels having more repeat phrases
Linear Growth Model F1,112 = 5.26; P = 0.023
Mager, et al. 2012
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