M u s k D u c k b ro o d p a r a s it is m
127
M usk Duck brood
parasitism on Black Swans
K. K r a a ije v e ld 1 & R . A . M u ld e r 2
' D e p a r t m e n t o f Z o o lo g y , U n iv e r s it y o f M e lb o u r n e , P a r k v ille , V ic 3 0 1 0 , A u s t r a lia .
C u r r e n t a d d r e s s : D e p a r t m e n t o f B io lo g y , D a r w in
B u i ld in g , U n iv e r s it y C o lle g e
Lo n d o n ,
G o w e r S tre e t, L o n d o n W C 1 E 6 B T, U K .
' D e p a r t m e n t o f Z o o L o g y , U n iv e r s it y o f M e lb o u r n e , P a r k v ille , V ic 3 0 1 0 , A u s t r a lia .
T h is
p a p e r d e s c rib e s
lo n g
in c u b a t io n
b e h a v io u r,
s it is m .
p a ra s it is m
th a t
B la c k
Swans
p a ra s it is m
Biziura Lobata.
a s th e y a re
u n lik e ly to
as
w e re
w h e th e r
used
to
te s t
is c o n s t r a i n e d
a b a n d o n m e n t),
d if f e re n t f r o m
b ro o d
p o t e n t ia lly s u ita b le
in t h i s s y s t e m
o r ne st
s h e lle d
e ggs
of
by M usk Duc ks
p e r io d , a n d
th e y a re
M o de l
t io n
Th e
in c id e n c e s
Cygnus atratus
Swans
o r egg
h o s ts
t h o u g h t to
be
fo r
M usk
th e
e ggs,
of
Th e
e ve n
Duck
of
(e g g
re s u lts
whe n
B la c k
ha ve
a
re je c tio n
succe ss
b y h o s t re s p o n s e s
t h e ir o w n . H o w e v e r, th e re w a s
m o de l e ggs,
n e s ts
e x h ib it e g g
s h e ll s tre n g t h .
re a d ily a c c e p t f o re ig n
of
B la c k S w a n s
p a ra
b ro o d
re c o g n i
sho we d
t h e y a re
v e ry
a s u b s t a n t ia l lo s s o f w e a k -
a c c id e n t a lly c ru s h e d
b y th e
swans.
re la t io n o f t h is to t h e u n u s u a lly t h ic k s h e ll o f M u s k D u c k e g g s
is d i s
cussed.
K e y W o r d s : in t e r s p e c if ic b ro o d p a r a s it is m , e g g r e c o g n it io n , e g g r e je c t io n , m o d e l e x p e r i
m e n t s , s h e ll t h ic k n e s s
In t e r s p e c i f i c
f e m a le s
n e s ts
of
o th e r
w id e s p re a d
Th e
b ro o d
p u rp o s e ly
p a ra s it is m ,
la y in g
am o ng
in
o r
th e
1 9 9 2 ).
m o s tly
Th e
h o s ts
i n v o lv e
of
p a ra s it ic
o t h e r w ild f o w l,
( La rid a e ) ,
w i l d f o w l ( A n a t id a e ) .
ib is e s
( T h re s k io rn it h id a e ) . T h e
been
of
le a s t 3 6 o u t o f
Π 6
p a rtic u la rly
c o m m o n
is
re c o rd e d
s p e c ie s
O x y u rin i
( s t if f -t a ile d
© W ild f o w l &
W e t la n d s
T ru s t
r e la t iv e ly
in a t
( 2 5 % ) , a n d is
a m o ng
duc ks;
th e
S a y le r
in te rs p e c if ic
b e c o n s tra in e d
C o o ts
b ro o d
w ild f o w l
b u t a ls o
Fulica sp.
g u lls
s p e c ie s ,
b e h a v io u r h a s
e ggs
p a ra s it is m
b y th e t im in g
and
succe ss
o f th e
m ay
p a r
a s it is m , a n d b y h o s t re s p o n s e s , s u c h a s
n e s t s it e
d e f e n c e , d is p la c e m e n t o f p a r-
W i l d f o w l ( 2 0 0 2 ) 5 3 : 1 2 7 -1 3 5
128
M u s k D u c k b ro o d p a r a s it is m
a s itic
e ggs,
e gg
re je c t io n
a b a nd o nm e nt
and
Fu rth e rm o re ,
p a ra s itic
1 9 9 2 ).
e ggs
m ay
dam age d whe n
q u ic k ly d e p o s ite d
ne st
th e
o r
whe n
p u n c tu re
as
s h e lls
ha ve
egg
e v o lv e d
m im ic ry
( D a v ie s
2 0 0 0 ).
egg
d is c rim in a t io n
( S o re n s o n
1997,
e t at.
Dugge r
c lu t c h
( M a llo ry
to
s h e lls
&
h a ve
&
p a ra s it is m
dence
a re
b o th
and
th e
th e
is
m o re
1 9 9 3 ).
do
a lt ric ia l
Th e
1 9 8 9 , Lyo n &
In
t h is
A u s t ra lia n
Duc ks
n e s ts
(R o h w e r
E a d ie
p a p e r,
h o s t -p a ra s it e
a
Biziura lobata
is
Swans
A lt h o u g h
M usk
Duc ks
ha ve
p a ra s ite s ( A tt iw il
e v i
to
p a ra s ite s
M a rc h a n t &
can
th e
Duc ks
M usk
(s e e
of
la rg e
Swans
a b ilit ie s .
ha ve
L a s t ly ,
asse ss
1 9 8 1 ), th e y
re c o rd e d
p a r
B la c k S w a n s . M u s k D u c k s a re
w h e th e r
M usk
h o s ts
Duc ks ,
m o de l e ggs
fo r
a
B la c k
b ro o d
f ie ld
egg
cost
to
u n lik e
e v o lv e d
in t h e
of
at o ur
s m a ll
e x tra
s m a lle r
th o s e
Th e
B la c k
F u rth e rm o re ,
p a re d
be
host
o v e r la p
M usk
to
to
of
a d d it io n a l
a
host
in c u b a t io n .
p e rio d s
Duc ks
an
th e
th e
c o m p a re d
n e s t s a re
kno wn
24
B la c k
w h ic h
ra te s o f B la c k S w a n
s u it a b le
d a ys
(a b o u t
b e f o re
M e th o d s ) .
pose
B la c k
to
Swans
41
h o s t a n d it w o u l d t h u s s e e m
re c o g n it io n
of
1 9 6 7 ).
1 9 9 0 ).
d u rin g
s h o rte r
and
not
am o unt
B la c k
H ig g in s
h a tc h
Swans
in c u b a tio n
of
in
o ff
o f f e r a r e la t iv e ly la r g e w i n
in c u b a t io n
s h o u ld
a m o ng
e ggs
e t al.
M usk
m a in
s t u d y s it e
t h e ir
abo ut
o p p o rt u n it y
p re
Cygnus atratus.
a re
of
th u s
of
w it h
F re e m a n
re p o rte d :
n o t p r e v io u s ly b e e n
a s it is in g
th a t
d a ys ,
do w
le a s t
M usk
1 9 7 7 ), c o n s id e r a b ly lo n g e r
th a n
Swans
at
n e s t ( F r it h
a v e ra g e
( B ra it h w a it e
Duc ks
w ild f o w l
fe e d
p e rio d
w ith
as
u n e xp e c te d
la y in g
B la c k
on
th e
s p e c ie s
c o m b in a t io n
w ild f o w l
ta k e s
M usk
c o n s id e ra b le
in c u b a t io n
ly t h a t
ra th e r
a
a f t e r le a v in g
p a ra s ite s
th o s e
&
d ire c t ly
th e
s t u d ie s
co m m o n,
in c u b a t io n ,
1 9 9 1 ).
of
b ro o d
to
fo r
a
th a t in te rs p e
by
unusual am o ng
f e m a le s
s p rin g
in
f u rth e r
c irc u m s ta n c e s .
f in is h e s
p a ra s it is m
th e
r e la t iv e ly
b ro o d
to
p a ra s it is m
p a ra s it is m
a re
as
re p o rt
c e rt a in
Duc ks
th a t
in t e r
is
o n ly o t h e r s tu d y to
egg
ta k e n
to
be
not
e t at.
p a ra s it ic
and
of
egg
1 9 9 0 ).
o fte n
c o m p a re d
yo u n g
no t
s p e c ie s
r e l a t i v e l y s m a l l in s p e c i e s w i t h
c o c ia l y o u n g ,
host
's tro n g e r'
h o s ts
c o s ts
m ay
und e r
Th e
in r e l a t i o n
b e n e f its
b ro o d
G o ld e n e y e
w e re
W e a th e rh e a d
in
im p o rta n t
n e e d e d , it is p o s s i b l e
c if ic
tim e
s p e c ie s
e v o lv e d
a re
c uc ullatus
n o n -p a ra s itic
w ild f o w l
th a t
h o s ts
1 9 9 9 a,
W e a th e rh e a d
la c k o f a d a p t a t io n s
am o ng
w ild
p e rip h e ry o f th e
p a ra s it ic
th a n
( M a llo ry
on
egg
h o s t s p e c ie s
Co m m o n
b e a t th e
Fu rth e rm o re ,
se e m
s tro n g
Duc k.
it is
p a ra s it is m
s tra te g y .
is t h e
and
A tt iw il
re p ro d u c t iv e
(1 9 8 1 )
ho w
b ro o d
b ro o d
e t at.
e ggs
p re s e n t
A lth o u g h
Lo pho dyte s
th a t
at
s p e c if ic
M usk
lit t le e v id e n c e f o r
am o ng
c le a r
s p e c ie s ,
in t e rs p e c if ic
b ro o d
a d a p t a t io n s
Dugge r
p o o rly -s t u d ie d
a v ia n
S tu d ie s
Buc e phaia c langula
lik e ly to
to
1 9 9 9 b ). A s tu d y o f H o o d e d
M e rg a n s e rs
re p o rte d
in t h e
a
In r e s p o n s e
and
fo w l ha ve s o fa r fo u n d
be
a tte m p ts
c o n s t ra in t s , s o m e
p a ra s ite s
such
host
it ( M a l l o r y 2 0 0 0 ) .
to t h e s e
ne st
(S a yte r
egg
p re d a tio n
lo w c o m
h o s ts .
Sw a ns
m a ke
p a ra s it is m
e x p e rim e n t
o f d if f e re n t m i m e t i c
To
by
u s in g
q u a li
t ie s a n d s h e l l s t r e n g t h w a s u n d e r t a k e n .
M u s k D u c k b ro o d p a r a s it is m
Study A re a and M e th o d s
fo u n d
by
w a d in g
a re a . T h e
Th e
Ju ly
s tu d y
and
w as
O c to b e r
c e n tra l
2000
V ic t o ria ,
W e n d o u re e
V ic t o ria
and
Re e dy
fo r
p la c e
Th e
b e tw e e n
s iz e
s e ve n
( K ra a ije v e ld 2 0 0 3 ). L a k e W e n d o u r e e
p e r m a n e n t la k e
o f 2 3 8 h a , w it h
la t io n
170
a re
o f a ro u n d
p re s e n t
y e a r. T h e
Ta ll
a t th e
swans
B la c k
s it e
b re e d
by cano e.
p e rm a n e n t
o c c u rs
No ve m b e r
p e rs .
re e d
re e d
a re
&
50 cm
d e p th .
about
130
w h ile
at
o th e r
s tu d y a re a
p re s e n t.
am o ng
swans
is
w e re
B la c k
W h it e
Swan
and
d o m e s t ic
an
a re a
p e rim e t e r o f
d u rin g
o f lo w
of
Reed
s tu d y
of
no
a re a ,
ye a r
swans
m o s t ly
and
p e r io d
th e
th e
th a n
th e
w e re
lo c a t e d
w e re
e a s ily
W e n d o u re e ,
re fu s e d
c lu t c h e s
b ro w n
c h ic k e n s ,
swan
e ggs
f ro m
th e
w e re
a ls o
used.
c o n t r o l.
and
e ggs
cam e
and
sam e
in v e s t ig a t e
w h it e
p a ris .
w e re
c he c ke d
a d d it io n
of
assum e d
th a t
p a rtn e rs
a
w o u ld
h a ve
had
swan
used
as
a
e x p e ri
in T a b le
1.
m o d e l egg.
tw o
m o d e l
e ggs
of
o f th e
one
d u rin g
th e
so m e
c h ic k e n
lis t e d
n e s t o n ly re c e iv e d
N e s ts
f ille d
S h e lls
d im e n s io n s
a re
in f e rt ile
p o p u la t io n
o r u n f ille d ) w e r e
Th e
age.
f ro m
e f f e c t o f s h e ll s tre n g t h , w e
of
s iz e ,
added
c am e
w h it is h
To
in
o f v a ry in g
duc ks,
add
S e ve n
w e re
e ggs
d o m e s t ic
b ro w n
le a v e
to
d if f e rin g
f ro m
th e
to
u n n o tic e d .
s h e ll s tre n g t h ,
a s ys te m
in h a b ite d
o f re e d s
to
w e re
d u rin g
it i m p o s s i b l e
m o de l e ggs,
Ea c h
of
at
e x p e rim e n t s w e re
e ggs
m e n ta l s tu d y e g g s
n u m e ro u s
No
re c o rd e d
La k e
La k e
K ra a ij e v e ld ,
w as
th e
N e s ts
s t rip s
K.
w a t e r o f le s s
d ry a n d
of
c o lo u r a n d
( f i l le d
s trip s
w as
typ e s
No
swans
e x p e rim e n t a l
e ggs
and
a t b o th
w e e k ly .
e x p e rim e n t s
m a k in g
1 9 8 3 ).
a t th e
c o n s is t e d
tim e s
th e
p la s t e r
th e
D u rin g
be cause
t h e ir n e s t,
of
Duc ks
e ve r
Re e d y
at
w it h
o n ly f lo o d s
n a rro w
c o n d u c te d
b re e d
S e p te m b e r
a ro u n d
a
at
k n o w n to
s t u d y s ite
Phragmite s aus tralis
has
W h e e le r
v e g e ta tio n
and
a ls o
o f a ll n e s t s
re c o g n it io n
2 0 -6 0
La k e
b e d s , w h ic h
Eg g
about
c o n t a in in g
Th e
s p rin g . T h e
ru s h e s
of
1967;
Re edy
o f a b o u t 9 0 ha
th e
la k e
by M usk
( F rith
la k e s
beds.
b y s e a rc h in g v e g
b e tw e e n
o b s .).
s h a llo w
t h ro u g h o u t th e
Th e
[Th o m a s
M o s t e g g -la y in g
s it e
who
m a i n l y in b e d s o f
p o p u la t io n
M u s k D u c k s , w h ic h
r e g u la rly
a po pu
Swans
Ele o c haris sphace late ,
S p ik e -ru s h
a n d n e s ts w e re fo u n d
e t a t io n
is a
s tu d y
R e e d y La k e .
S e p te m b e r 2 0 0 0 .
in
th e
m o n it o re d
w e re
ne ar
e a rly Ju ly
and
Duc ks
m a in
c lu t c h
tw o
M usk
w e re
c o n d u c te d
Swans
b e tw e e n
and
in
La k e
La k e ,
B la c k
m id -N o v e m b e r
v a rie s
s it e s
c o n te n ts
s t u d y s it e s
(S 3 7 ° 3 3 '
E 1 4 -4 -° 2 6 ' ) .
p e r io d
ta k e s
tw o
B a lla ra t
(S 3 8 ° 1 1
in c u b a t io n
at
b e tw e e n
A u s t ra lia :
in
E 1 4 -3 ° 4 -9 ’ )
G e e lo n g
and
c o n d u c te d
th ro u g h
129
d a ys
e gg.
t h is
a fte r
It
w as
t im e
an
b o th
o p p o r t u n it y
to re je c t t h e m o d e l e g g s . A l l e x p e r i m e n t s
d e s c rib e d
b y th e
in t h i s
A n im a l
C o m m it t e e
p a p e r w e re
a p p ro v e d
E x p e rim e n t a t io n
at
th e
E th ic s
U n iv e rs ity
of
M e lb o u rn e .
To
M usk
asse ss
Duc ks
e xp e c te d
a p p ro a c h
f ro m
w h e t h e r th e
f ro m
of
egg
is s t r o n g e r t h a n
it s s i z e , w e
M a llo ry
M a llo ry
f o llo w e d
(2 0 0 0 ),
e t al.
s h e ll o f
w o u ld
u s in g
(1 9 9 0 ).
be
th e
d a ta
L in e a r
130
M u s k D u c k b ro o d p a r a s it is m
re g re s s io n
was
r e la t io n s h ip s
used
b e tw e e n
s h e ll t h ic k n e s s ,
shape .
A ll
o r
h is t o g ra m .
d ic t iv e
s h e ll
w e re
A
se co nd
on
re g re s s io n
a ll
t h ic k n e s s
fo r
based
c o m p a re d
to
egg
egg
egg
as a
was
p re
and
m ass.
M u s k D u c k e g g w e re
th e
9 5 %
c o n f id e n c e
p r e d ic t e d v a lu e . D a t a o n
c h a ra c t e ris t ic s
a n d te s te d
w e re
lo g e
f o r n o r m a lit y .
R esults
and
w a te rf o w l,
shape
on
th e
in it ia lly
M u s k D u c k , to g e n e ra t e
in t e r v a ls o f t h e
egg
and
r e s id u a ls p lo t t e d
e q u a t io n s
fo rm e d
m ass
m ass
T h e v a lu e s f o r th e
th e n
egg
egg
p e rfo rm e d
e xc e p t th e
e x a m in e
w a te rf o w l
in c lu d e d , a n d t h e
th e n
to
tra n s
At
La k e
W e n d o u re e
n e s ts w e re
a ll n e s ts
66
B la c k
lo c a t e d , c o n s t it u t in g
on
th e
la k e ,
and
Swan
9 5 %
th re e
of
n e s ts
( 5 % ) c o n t a in e d a M u s k D u c k e g g . T h e s e
e g g s w e re
g re e n is h w h it e
u n m a rk e d ,
s lig h t ly
th a n
Swan
B la c k
lig h t e r
e ggs,
a b l y s m a l l e r ( Ta b le
in c o l o u r a n d
in
and
c o lo u r
c o n s id e r
1 ). O n e w a s f o u n d in
a c l u t c h o f f iv e s w a n e g g s , 2 1 d a y s a f t e r
th e
c lu t c h
had
been
c o m p le t e d .
Th e
e g g w a s s t i l l p r e s e n t in t h e
n e s t 17 d a ys
la t e r, a f t e r t h e
had
and
th e
e gg
c yg n e ts
w as
c o ld
d e v e lo p e d
second
swan
had
and
M usk
M usk
e ggs
Duck
c lu t c h
of fo u r s w a n
c lu t c h
c o m p le t io n .
le f t t h e
n e s t. Th e
c o n ta in e d
Duc k
egg
h a tc h e d
a
e m b ryo .
w as
fo u n d
e ggs , 20
T h is
d a ys
egg
was
f u lly
Th e
in a
a fte r
s t ill
T a b le 1 . D i m e n s i o n s ( m m ± S D ] o f d if f e re n t t y p e s o f e g g s f o u n d in n e s t s o f B la c k S w a n s a n d
o f th o s e
use d
in e g g
r e c o g n it io n e x p e r i m e n t s ( th e
la t t e r a re
m a rk e d w i t h * ).
A l l e g g s a re
p la in in c o lo u r.
Le n g t h
W id t h
B la c k S w a n ( n = 3 3 )
106 ±3
67+2
P a le G re e n
M u s k D u c k (n = 2 )
5 8 ±1
4 7+7
P a le G r e e n i s h - w h it e
W h i t e Ib is (n= 1 )
68
47
* C h ic k e n ( n = 1 6 )
57±2
4 3 ±1
B r o w n o r W h it e
* D u c k (n= 1 2 )
62±3
4 7 ±1
W h ite
E g g Ty p e
C o lo u r
W h it e
M u s k D u c k b ro o d p a r a s it is m
p re s e n t
swan
in
th e
e ggs
ne st
14
h a tc h e d
d a y s la t e r, s o t h e
h a ve
been
Th e
e v e n tu a l
d a ys
a
la t e r .
f u rth e r
Th e
s e ve n
M u s k D u c k e g g c o u ld
in c u b a te d
fa te
f o r o v e r 21
of
t h is
As
th is
e a s ily a c c e s s ib le ,
n e s ts
w as
about
day
by
600m
th e
a
f ro m
swan
c yg n e ts
p a re n t
th e
ne st
p a ir
a w a y f ro m
w as
w e re
th e
th e
se e n
n e s t.
Th e
a fte r
swan
th e
ju d g in g
s e ve n
e g g s . T h is
c lu t c h
f ro m
d a ys
was
th e
o ld
ne st w a s
h a t c h in g
whe n
d a te
fo u n d .
1.
w ith
d e s e rte d
t h ird
e gg.
but
in to
M usk
c lu t c h e s
re m a in e d
w e re
canno t
h a ve
lo n g e r
th a n
of swan
e ggs
in t a c t a n d
d e s e rte d
been
15
in a l l t h e
no ne
o f th e
a f t e r b e in g
A t R e e d y La k e , 31
in
d a ys .
a re a
it is
at
lik e ly
o f th e
c o n ta in e d
M usk
th e
Th e
Exa c t
f ro m
of
th a t
tw o
had
th e
w e re
been
m o de l e ggs
th e
c h ic k e n
a fte r
ne st cup
tw o
p la s t e r
e ggs
e ggs
been
o r b u rie d
lo w ,
in
but
e g g s h e lls
used
( F is h e r
P la s t e r-f ille d
n o t d if f e r s ig n if i c a n t ly
c o n tro l s w a n
9
in c u b a t
had
was
w e re
in
w a rm ,
re m a in in g
d a ys
P < 0 .0 0 0 1 ],
d id
m o de l
p e rc e n ta g e
s ig n if ic a n t ly w h e n
te s t,
in F i g u r e
re m a in e d
d a ys
th a t th e y
w it h
c h ic k e n
p a ra s itis e d .
n e s ts w e re fo u n d a n d
re c o g n it io n
n e s t m a t e ria l. T h e
in c r e a s e d
n e s ts
e ggs
o f th e
ne st
f ille d
a d d it io n
a fte r
n o rm a l
n e s ts
egg
e x p e rim e n t a l n e s ts w e re
o u t s id e
th e
th e
s u m m a ris e d
m o de l
No ne
pushed
we e k
of
Duck
of
a fte r
A ll
in d ic a t in g
th e
fo r
o f th e
n e s ts
ed.
la t e r t h e e g g h a d d is a p p e a r e d . T h u s t h e
ne st
No ne
th e
it w a s
A
s tu d y
lo c a t e d . N o n e
La k e
re s u lts
f ir s t
fo u n d
c o m p le t e d ,
Re e dy
e x p e r im e n t s a re
M u s k D u c k e g g w a s f o u n d w it h a c lu t c h
o f tw o
at
Th e
o b s e rv e d
on
is
th e
Duck eggs.
u n k n o w n , b u t a M u s k D u c k c h ic k u n a c
c o m p a n ie d
s ite
a ll o f
t h a t a ll n e s t s w e r e
d a ys .
e gg
m o n ito re d .
131
e ggs
in
t h e ir lik e li-
8
100 r
»
80
cn
60
m
40
cć
20
16
□
N o rm a l
■
P la s te r f ille d
à?
W h ite
B ro w n
c h ic k e n
c h ic k e n
Swan
Duck
Eg g typ e
F ig u r e
1 . P e r c e n t a g e o f e x p e r im e n t a l e g g s r e m a in in g
t io n . S a m p le
s iz e s a re
in d ic a t e d a b o v e t h e
b a rs . N o
in t h e
n e s t s o f B la c k S w a n s t w o
p la s t e r - f il l e d
d u c k e g g s w e re
used.
d a y s a f t e r a d d i
132
M u s k D u c k b ro o d p a r a s it is m
hoo d
of
s lig h t ly
re m a in in g
h ig h e r
in
th e
n e s t.
p e rc e n ta g e
of
duck e ggs
re m a in in g
in t h e
c o m p a re d
to
c h ic k e n
u n f ille d
n o t s ig n if ic a n t a n d
b e tw e e n
e ggs
o f d if f e re n t
hood
o f re m a in in g
F ig u re
egg
m ass
th e
M usk
re s id u a l,
Ho o d e d
is
of
Duck
M e rg a n s e r.
m ass
can
la rg e
to
o n th e
ha ve
p re d ic tio n
is
0 .7 0 m m
w h ic h
o f th e
f a lls
a
of
in t e r v a l
o f 0 .3 7 - 0 . 6 5 m m . T h e
e t at.
[ M a llo ry
o u t s id e
ly t h i c k e r t h a n
on
egg
t h is
of
of
Duck
re g re s s io n ,
s h e ll
f ro m
th a t th e s h a p e
egg
th e
M usk
e xp e c te d
s im ila r a n a ly s is
p o s it iv e
th a t
p re d ic te d
to
1 9 9 0 ),
c o n f id e n c e
i n t e r v a l , i n d i c a t i n g t h a t it is s i g n i f i c a n t
th ic k n e s s
W he n
th e
be
b y th e
a
o n ly
f ro m
M u s k D u c k e g g ) is
s h e ll th ic k n e s s
e gg
lik e li
re s id u a ls
has
( th e
a v e ra g e s h e ll t h ic k n e s s o f a M u s k D u c k
n e s t.
s h e ll
128g egg
0 . 4 9 m m , w it h a 9 5 % c o n f id e n c e
c h ic k e n
f o r a ll w a t e r f o w l. T h e
re m o v e d
egg
th e
e q u a t io n , a
p re d ic te d
e ggs was
t h e ir
t h is
w e ig h t o f a n a v e ra g e
n e s ts
n o s ig n if ic a n t
in
in t h e
egg
second
t h ic k n e s s
u n f ille d
swan
u n f ille d
c o lo u r
2 sho w s
re g re s s io n
Fro m
p ro b a b ly d u e to t h e ir
s t r o n g e r s h e ll. T h e r e w a s
d if f e re n c e
Th e
th e
is
on
egg
f o r its m a s s . A
shape
in d e x f o r t h e
n o t d if f e re n t f r o m
sho we d
M usk Duck
th e
e x p e c te d
v a lu e . E g g s h a p e
c a n b e p re d ic te d
egg
e q u a t io n :
m ass
b y th e
f ro m
L o g e s h a p e = 0 .0 9 6 + 0 .0 5 9 ( L o g e m a s s ) ;
e q u a t io n :
R 2= 0 . 4 4 , F 1 , 1 2 0 = 9 3 .9 0 , P< 0 .0 0 1
L o g e t h ic k n e s s = -2 . 8 4 7 + 0 .4 4 0 ( Lo g e m a s s ) ;
Fro m
R 2= 0 . 7 7 , F 1120= 4 0 8 .9 , P< 0 .0 0 1
t h is
p r e d ic t e d
1 .4 6 2 ,
w it h
to
e q u a t io n ,
ha ve
a
9 5 %
a
a
128g
shape
egg
in d e x
c o n f id e n c e
is
of
in t e rv a l
35
30
» 2 5
0
§ 20
1 15
¿ 10
5
0
-0.3 -0.2 -0.1
0
0.1
0.2 0.3 0.4 0.5 0.6
Residual
F ig u r e
2 . H is t o g r a m
o f r e s id u a l v a lu e s f r o m
s p e c ie s o f w a t e r f o w l [ d a t a f r o m
th e
r e g r e s s io n
M a l lo r y e f a í. 1 9 9 0 ). T h e
o f e g g s h e l l t h ic k n e s s
on egg
m a s s fo r 122
M u s k D u c k is in d ic a t e d w it h a n a s t e r ix .
M u s k D u c k b ro o d p a r a s it is m
on
th e
p re d ic tio n
shape
in d e x
of
1 .5 0 3
( M a llo ry
in s id e
th is
not
a
Ί .3 5
M usk
e t al.
shape
-
1 .5 8 .
Duck
1 9 9 0 ),
c o n f id e n c e
in g t h a t t h e
is
of
egg
w h ic h
in t e rv a l,
of a M usk
s ig n if ic a n t ly
Th e
is
f a lls
in d ic a t
Duc k egg
d if f e re n t
f ro m
th a t
p r e d ic t e d .
s m a lle r
f irs t
re q u is it e
w in d o w .
e x p e rim e n t a l
n e s ts s e e m s
s it ic
had
e ggs
c h ic k e n
0 .3 3 - 0 .3 6 m m
t h in
Nwo su
e t al.
be cause
was
whe n
s im ila r
w it h
p la s t e r
b y th e
p a ra s it ic
th a t
of
B la c k
Duck
e ggs
b e in g
c ru s h e d
a c c id e n t a lly
swans.
added,
whe n
d id
b e h a v io u r,
f ille d
th e s e
w e re
h ig h lig h t s
in t e rp re t in g
t h e ir
o r
not
d is p la y
egg
whe n
p re
e ve n
th a t w e re
own.
In
any chance
o f h a t c h in g , th e
egg
(i)
h o s t n e s t w ith in
th e
s ta rt
c lu t c h ,
s tro n g
of a
do w
swan
of
and
th e
(ii)
to
to
B la c k S w a n .
ha ve
Eve n
is
lo n g
to
p a ra
d e p o s ite d
in
f irs t 1 7 d a y s o f
of
a
th e
host
s h e ll th a t
w it h s t a n d
o p p o rt u n it y f o r
ne st
be
in c u b a t io n
e no ugh
of
to
v e ry
o rd e r
ha ve
needs:
a n t i-
s tu d y s u g g e s ts
m o de l e ggs
f ro m
fa c t
e ggs
s w a n s . T h is
Swans
T h is
b y th e
s it ic
th e
is
th e
th o u g h
w e ig h t
th e
p a ra s it is m
c o m p a re d
to
is
w in
of a
th a t
of
th e
th e
m ass
b a s ic
been
of
M usk
to
in c u b a t in g
a v o id
swan,
th ic k e r
whe n
w a t e rf o w l.
th e
a ls o
e no ugh
by an
s tu d y
w ith in
s h e ll
s tro n g
f o r it s
th is
It h a s
s u b s ta n t ia lly
o th e r
o b s e rv e d
in
o c c u rre d
th a t
a re
s tu d y o f th e
th a n
c o m p a re d
W it h o u t
f u rth e r
b io lo g y o f th e
M usk
D u c k , it r e m a i n s
u n c le a r w h e t h e r t h ic k
s h e lls
b y th e
p ro d u c e d
s p e c ie s
a re
an
e v o lu t io n a ry a d a p t a t io n to p a ra s it is m
of
B la c k
of
so m e
Swans,
o r
a s itis m
a re
a re
a
b y -p ro d u c t
o t h e r f u n c t io n .
It is p o s s i b l e
1998;
p ro b a b ly d is a p
e g g -re c o g n it io n
w it h
d if f e re n t
e t at.
Ve rn a
b e h a v io u r . T h e
re c o g n it io n
s e n te d
abo ut
m o de l
re q u ire d
o ur
s h e lls
s u p p o rte d
w e re
of
( th e
in c u b a t in g
th a t
e v id e n c e
m any
th e y w e re
s u g g e s t io n
Swan
g e n e ra lly
1987) and
b y th e
of
a n ti-p a ra -
s h e lls
a re
t h ic k ,
p e a re d
c a u tio n
B la c k
H o w e v e r,
m o de l e ggs
a c c e p te d
f ro m
c o n s is t e n t w it h
of
th e
d is a p p e a ra n c e
e ggs
b e h a v io u r .
c ru s h e d
th e
tim e
d e m o n s tra te d
e xp e c te d
s ig h t ,
h o s ts ,
p a ra s it is m
h a ve
to
At
of
a p p e a r n o t to
and
Discussion
p o t e n t ia l
in c id e n c e s
133
due
h o s ts .
th a t in c id e n c e s
to
a
la c k
of
P r e v io u s ly ,
been
n e s ts
M usk
re c o rd e d
H a rd h e a d
tralis,
Duck
me mbranac e us,
( A tt iw il
e t al.
B la c k
Duck
b re e d
w h ile
s m a ll
at
La k e
n e s ts w e re
(Th o m a s
o f p a ra s it ic
b re e d s
in
&
W h e e le r
w e re
o b s e rv e d
w it h
B la c k
o th e r h o s t
' a v a ila b le ' .
Swan,
e x p e rim e n t a l e g g s
n e s ts w e re
W e n d o u re e ,
u n lik e ly th a t n o
B la c k
m a rk in g s
P a c if ic
M o o rh e n
Duck
c o n c u rre n tly
it is
and
te ne bro sa
Dusky
m a n y o f th e s e
b re e d in g
Swans,
Th e
th e
B lu e -b ille d
n u m b e rs
1 9 8 3 ). A s
Duck
1 9 8 1 ). O f t h e s e , t h e
c o m m o n ly
th e
G re y Te a l
Aythya aus
Gallinula
and
h a ve
P a c if ic
Malacorhynchus
B lu e -b ille d
M o o rh e n
o th e r
Duc ks
Anas gibbe rifro ns,
P in k -e a re d
of
p a ra s it is in g
Anas supe rc ilio sa,
B la c k D u c k
Dusky
o f p a r
o f B la c k S w a n s a t t h e s t u d y s it e
M usk
Duck,
th a t w e re
and
added
to
p la in
in c o l o u r .
Th e
m ig h t
c o n s t ra in
re c o g n it io n
e ggs
b y th e
h o s t.
la c k o f
H o w e v e r,
1 3 4 - B la c k D u c k b ro o d p a r a s it is m
th is s e e m s
o ur
u n lik e ly , a s t h e e g g s u s e d
e x p e rim e n t
B la c k
Swan
D ie d e rik
a ls o
e ggs
d if f e re d
c o lo u r
s e v e ra l
s p e c ie s
of
( D a v ie s
2 0 0 0 ), a n d
in t h i s
s ys te m
b o th
u n m a rk e d
th e
host
is
h a ve
a b le
to
Th e
succe ss
re p ro d u c t iv e
f a c ilit a t e d
h o s t -p a ra s it e
e ggs
and
p a ra s itic
depend
of
th e
o th e r
on
to
be
( F rith
th e
yo u n g
m a jo rit y
in c lu d in g
egg
of
a
s tu d y
at
La k e
of
yo u n g
de pe nde nt
t h e y le a v e
f e m a le s
th e
a re
p o t e n t ia l
B la c k
Swans,
do
b e h a v io u r,
it w o u l d
se e m
not
on
nest
kno wn
s e v e ra l w e e k s .
t h e ir
s u rv iv a l c h a n c e s
o f th e
lin g
lo w
w o u ld
c o lle c t t h e
f in is h e d
be
to
As
h o s ts ,
Re edy
La k e .
p o rte d
by
W ild lif e
L e s lie
T h is
g ra n ts
R e s e a rc h
B ird
re f e re e s
th e
d u c k lin g s
in c u b a t io n .
once
Such
p r o v id e d
w as
s up
f ro m
th e
H o ls w o rt h
Fu n d
and
th e
and
Fu n d .
tw o
S tu a rt
F e m m ie
a n o n ym o u s
u s e fu l c o m m e n ts
on
m a n u s c rip t .
R e feren ces
A t t iw i l,
A. R .,
1981.
B o u rn e ,
P o s s ib le
A u s t r a l ia n
O x y u rin i) .
J. M .
s t i f f -t a i le d
Emu
&
P a rk e r,
n e s t -p a r a s it is m
d uc ks
S . A.
in
th e
( A n a t id a e :
8 1 :4 -1 -4 2 .
B r a it h w a it e , L. W . 1 9 7 7 . E c o lo g i c a l s t u d ie s o f
th e
B la c k
Swan.
in c u b a t io n .
I. T h e
e gg,
c lu t c h
and
Australian Wildlife Research
4:
5 9 -7 9 .
N .B .
2000.
othe r cheats.
Cuckoos, cow/birds and
T & A D P o y s e r, L o n d o n .
d uc k
f e m a le s
th e
re s e a rc h
R e s e a rc h
e x h ib it
th a t th e
p a ra s it ic
u n le s s
and
P a r k s V ic t o ria f o r p e r m is s io n to w o r k a t
D a v ie s ,
such
co nduct
W e n d o u re e
and
m o st
Duck
to
and
be
H o w e v e r,
yo u n g
m o re
fo r
to
s tre n g th
M usk
once
1 9 6 7 ), a n d
of
as
a p p e a rs
p a ra s it is m .
fa r
p a re n t a l c a re
Duc ks
a c c e p ta n c e , a n d
p re c o c ia l
w a t e rb ird s ,
appe ar
p a ra s it is m
M uck
s tra te g y
t im in g
u n lik e
b ro o d
by
by host e gg
m a y a ls o
th e
of
Sw a ns
R e s o u rc e s
E n v iro n m e n t f o r p e rm is s io n
K ra a ije v e ld -S m it
B la c k
fe e d
N a tu ra l
t h is
eggs.
th e
of
s iz e .
W e a v e rs
re c o g n is e
D e p t,
f ro m
and
Chryso c o c c yx c aprius
Cuc ko o
p a ra s it is e
in
in
ho st has
re t rie v a l
of
D u g g e r , B . D . , B lu m s , P. & F r e d r i c k s o n , L. H .
1 9 9 9 a . H o s t re s p o n s e to b ro o d p a r a s i t i s m
in t w o s p e c i e s o f d iv in g d u c k .
Wildfowl 5 0 :
6 9 -7 6 .
yo u n g
u n iq u e
f ro m
p a ra s it is e d
am o ng
2000) and
has
b ro o d
n e s ts w o u ld
p a ra s ite s
not be en
be
( D a v ie s
D u g g e r,
B .D .,
F r e d r ic k s o n ,
o b s e rv e d .
B o llm a n n ,
L.H .· 1 9 9 9 b.
L. C .
&
Re spo nse
of
f e m a le H o o d e d M e r g a n s e r s to e g g s o f a n
i n t e r s p e c i f ic
A c k n o w le d g e m e n ts
We
w o u ld
lik e
to
th a n k
b e rs o f th e
B a lla r a t F ie ld
p a rt ic u la r
Jo h n
C a ro l
H a ll,
and
B ria n ,
t h e ir
th e
m e m
N a t u r a l i s t s , in
E la in e
K e v in
h e lp
b ro o d
p a ra s ite .
Auk
116:
2 6 9 -2 7 3 .
in
G re g u rk e ,
and
fo r
th a n k th e
B a lla ra t C it y C o u n c il a n d
f ie ld .
H . J.
1967.
Wate rfowl in Australia.
A n g u s & R o b e rt s o n , S yd n e y.
We
K. 2 0 0 3 . Breeding ecology and
the evolution of mutual ornamentation in
the Black Swan. P h D t h e s is , U n i v e r s i t y o f
th e
M e lb o u r n e , A u s t r a li a .
Jo a n
A n d re w s
Frith ,
K ra a ije v e ld ,
B la c k D u c k b ro o d p a r a s it is m
Lyo n ,
B .E.
&
E a d ie ,
J. M .
1991.
Mode
of
d e v e lo p m e n t a n d in t e rs p e c if ic a v ia n b ro o d
Behavioural. Ecoiogy 2 :
p a ra s it is m .
3 0 9 -3 1 8 .
M a llo ry , M . L. 2 0 0 0 . T h e B la c k - h e a d e d D u c k
Heteronetta atricapiiia
Wildfowl 5 1 : 1 0 9 -1 1 5 .
la y s o r d in a ry e g g s .
Th o m a s ,
R.
Ballarat
&
W h e e le r ,
re gion.
M . L.
&
on
W e a th e rh e a d ,
M a llo ry ,
P . J.
1990.
a n d n e s t lo c a
e g g s h e ll s tre n g th
Condor 9 2 :
in
w a t e r f o w l.
1 0 3 1 -1 0 3 9 .
M . L.
&
W e a th e rh e a d ,
P . J.
1993.
R e s p o n s e s o f n e s t in g M e r g a n s e r s to p a r
a s it ic
Co m m o n
Behaviour 4 6 :
G o ld e n e y e
Animal
e ggs.
1 2 2 6 -1 2 2 8 .
Handbook
of Australian, Ne w Ze aland and Antarctic
birds. Vol. I: Ratite s to Ducks. O x f o rd
M a rc h a n t , S . & H ig g in s , P . J. 1 9 9 0 .
U n i v e r s i t y P re s s , O x f o rd .
Nw o s u,
C.C.,
1987.
O m e je ,
Ef f e c ts
of
S . S . I.
g e n o typ e ,
&
Ik e m e ,
age
A. i.
and
e gg
s iz e o n m e a s u r e s o f s h e l l q u a li t y o f lo c a l
and
c ro s s b re d
he ns.
Production Research
Journal of Animal
7 : 1 9 -2 8 .
R o w h e r , F. C . & F r e e m a n , S . 1 9 8 7 . T h e
d is
t r i b u t io n o f c o n s p e c if ic n e s t p a r a s i t i s m
b ird s .
Canadian Journal of Zoology 6 7 :
in
239-
253.
S a y le r, R . D .
1 9 9 2 . E c o lo g y a n d
e v o lu t io n o f
Ecology
and management of bree ding waterfowl.
b ro o d p a r a s i t i s m in w a t e r f o w l . In :
(e d s .
B . D . J.
B a tt,
A.D .
Afto n ,
M .G.
A n d e r s o n , C . D . A n k n e y , D . H . Jo h n s o n , A.
K a d le c
&
M in n e s o t a
G . L.
K ra p u ) .
P re s s ,
U n iv e rs it y
M in n e a p o lis ,
pp
of
290-
322.
S o re n s o n ,
M .D.
1997.
Ef f e c ts
o f in t ra - a n d
in t e r s p e c if ic b ro o d p a r a s i t i s m o n a p r e c o
c ia l
h o s t,
th e
Ca nva s b a c k
valisine ria. Behavioural Ecology
161.
Birds of
V ic t o ria ,
Ve rm a ,
S . V. S . ,
Go wda,
S .K.
&
E la n g o v a n ,
A. V. 1 9 9 8 . R e s p o n s e o f s in g le c o m b W h i t e
L e g h o r n la y e rs to d i e t a r y in c lu s io n o f ra w
Ef f e c ts o f n e s t p a ra s itis m
tio n
1983.
A u s t r a li a .
n e e m Azadirachta indica
Animal Fe ed Scie nce &
o r a lk a l i- t r e a t e d
M a llo ry ,
J.
R .Th o m a s ,
135
Aythya
8:
153-
k e rn e l
m e a l.
Technology 7 6 :
1 6 9 -1 7 5 .
136
Ken Kraaijeveld