Image
AI
ge e ated
I
1958,
Clippe to
Isla d
was
a
ve y
diffe e t
place
f om
the
huge
seabi d
colo y
it
would
late
become.
The
ti y
Pacific
atoll
had
o ce
suppo ted
thousa ds
of
b eedi g
bi ds,
but
decades
of
huma
occupatio
had
left
a
heavy
ma k.
Fe al
pigs,
i t oduced
whe
people
settled
o
the
isla d,
had
multiplied
a d
we e
feedi g
o
la d
c abs
a d
distu bi g
esti g
bi ds.
Whe
Ame ica
o ithologist
Ke eth
Stage
a ived,
o ly
about
650
B ow
a d
Masked
Boobies
emai ed.
He
emoved
all
58
pigs
f om
the
isla d.
The
cha ge
that
followed
was
g adual
but
st iki g.
With
the
pigs
go e,
la d
c abs
ecove ed,
vegetatio
was
kept
i
check,
a d
the
ope
g ou d
favou ed
by
the
boobies
emai ed
available.
By
2003,
ae ial
photog aphs
showed
mo e
tha
137,000
B ow
a d
Masked
Boobies
b eedi g
o
Clippe to ,
tu i g
a
sto y
of
ecological
damage
i to
o e
of
the
most
st iki g
seabi d
ecove ies
eco ded
o
a
isolated
isla d.
How
huma
settleme t
cha ged
Clippe to
Isla d’s
atu al
ecosystem
Clippe to
had
bee
desc ibed
by
ea ly
explo e s
as
a
place
c owded
with
t opical
seabi ds.
The
exposed
la d
cove s
o ly
about
1.6
squa e
kilomet es,
a d
the
la dscape
was
la gely
ba e .
That
cha ged
afte
people
settled
the e
i
the
late
19th
ce tu y
to
exploit
its
gua o
deposits.
Acco di g
to
a
2005
pape
published
i
Ma i e
O ithology
titled
‘Clippe to
Isla d:
Pig
sty,
at
hole
a d
booby
p ize’,
the
huma
occupatio
i t oduced
two
lasti g
cha ges:
coco ut
palms
we e
b ought
to
a
othe wise
la gely
pla t-f ee
isla d,
a d
pigs
we e
eleased
the e.
Du i g
the
yea s
that
followed,
the
pigs
became
fe al
a d
bega
feedi g
heavily
o
the
isla d’s
la ge
populatio
of
la d
c abs
as
well
as
affecti g
the
g ou d- esti g
bi ds.The
co seque ces
we e
al eady
seve e
by
the
time
Stage
a ived.
Pitma
a d
his
co-autho s
epo ted
that
thousa ds
of
Masked
a d
B ow
Boobies
had
o ce
b ed
o
Clippe to ,
but
Stage ‘s
1958
visit
fou d
o ly
650
bi ds
betwee
the
two
species.
The
pigs
had
alte ed
the
isla d
i
ways
that
eached
beyo d
the
bi ds
themselves.
Image
AI
ge e ated
How
Ke eth
Stage
emoved
58
fe al
pigs
f om
Clippe to
Isla d
The
solutio
was
u usually
di ect.
Stage ,
a
o ithologist
f om
the
Los
A geles
Cou ty
Museum,
killed
all
58
fe al
pigs
he
fou d
o
the
isla d.
He
a ived
with
a
shotgu
a d
emoved
the
a imals
afte
seei g
the
damage
they
we e
causi g
to
Clippe to ‘s
wildlife.
What
happe ed
afte wa ds
was
ot
simply
a
matte
of
emovi g
a
p edato
a d
waiti g
fo
bi ds
to
etu .
The
pigs
had
bee
eati g
the
isla d’s
la d
c abs,
a d
those
c abs
played
a
impo ta t
pa t
i
co t olli g
vegetatio .
With
the
pigs
go e,
the
c ab
populatio
ecove ed.
The
c abs
the
co sumed
much
of
the
vegetatio
a d
you g
coco ut
palms,
helpi g
etu
Clippe to
towa ds
the
spa se
la dscape
that
had
existed
befo e
the
huma
settleme t.That
elatio ship
betwee
pigs,
c abs,
pla ts
a d
seabi ds
became
a
impo ta t
pa t
of
the
isla d’s
ecological
sto y.
The
pigs
we e
ot
me ely
attacki g
bi ds.
They
we e
cha gi g
the
food
web
a ou d
them,
a d
those
cha ges
we e
affecti g
what
the
isla d
could
suppo t.
How
Clippe to
Isla d
we t
f om
650
boobies
i
1958
to
mo e
tha
137,000
The
scale
of
the
ecove y
o ly
became
clea
much
late .
Usi g
ae ial
photog aphs
take
i
2003,
Pitma ,
Balla ce
a d
Bost
cou ted
at
least
25,000
B ow
Boobies
a d
mo e
tha
112,000
Masked
Boobies.
Togethe ,
that
put
the
two
populatio s
at
mo e
tha
137,000
bi ds,
compa ed
with
the
app oximately
650
eco ded
by
Stage
i
1958.The
i c ease
was
especially
st iki g
fo
Masked
Boobies.
The
autho s
desc ibed
Clippe to
as
the
wo ld’s
la gest
k ow
colo y
of
the
species
at
the
time
a d
suggested
that
pe haps
half
of
the
global
populatio
might
have
bee
b eedi g
o
the
ti y
atoll.
Thei
figu es
also
placed
Clippe to
amo g
the
most
impo ta t
b eedi g
sites
k ow
fo
B ow
Boobies.The e
was
a othe
ecological
cha ge
that
helped
explai
why
the
isla d
looked
so
diffe e t
afte
the
pigs
disappea ed.
With
la d
c abs
o
lo ge
bei g
supp essed
by
pigs,
vegetatio
was
agai
kept
to
elatively
small
a eas.
The
c abs
also
co sumed
ewly
sp outi g
coco ut
palms,
limiti g
the
sp ead
of
t ees
ac oss
g ou d
that
the
Masked
Boobies
used
fo
esti g.
It
mea t
that
emovi g
o e
i t oduced
a imal
had
helped
esto e
a
much
la ge
elatio ship
betwee
the
isla d’s
pla ts,
c abs
a d
bi ds.
Black
Rats
sp ead
ac oss
Clippe to
Isla d
i
the
ea ly
2000s
By
the
1980s,
Pitma
a d
his
colleagues
we e
seei g
a
isla d
whe e
vegetatio
emai ed
est icted
la gely
to
small
lagoo
islets
a d
scatte ed
coco ut
palms.
The
a othe
i t oduced
species
a ived.
Two
fishi g
boats
w ecked
o
Clippe to
betwee
1999
a d
2000.
Du i g
the
followi g
yea ,
the
esea che s
eco ded
the
fi st
Black
Rats
they
had
see
o
the
isla d.
By
2003,
the
ats
we e
commo ,
a d
vegetatio
had
begu
sp eadi g
o to
the
mai
isla d
fo
the
fi st
time
i
decades.Whe
the
esea che s
etu ed
du i g
a
F e ch
expeditio
i
2005,
they
fou d
ats
feedi g
heavily
o
la d
c abs.
As
the
c ab
populatio
fell,
p eviously
ba e
co al
a eas
bega
ca yi g
de se
patches
of
vegetatio .
New
pla t
species
appea ed,
a d
hu d eds
of
coco ut
palms
bega
to
establish
themselves.The
shift
was
impo ta t
because
the
ats
we e
effectively
pushi g
the
isla d
i
the
opposite
ecological
di ectio
f om
the
o e
that
had
followed
the
pig
emoval.
Fewe
c abs
mea t
less
g azi g
o
vegetatio ,
while
mo e
vegetatio
c eated
additio al
habitat
fo
ats.
Pitma
a d
his
colleagues
wa ed
that
this
could
become
a
self- ei fo ci g
cycle.Rats
bega
eati g
seabi d
eggs
a d
chicks
o
Clippe to
Isla dThe
ats
we e
ot
o ly
cha gi g
the
la dscape.
They
we e
begi i g
to
affect
the
bi ds
di ectly.
O
small
lagoo
islets
whe e
Sooty
Te s
b ed,
the
esea che s
fou d
ve y
few
eggs
du i g
thei
2005
visit.
O e
had
ece tly
bee
laid,
o e
had
bee
eate
by
a
at.
Pitma ,
Balla ce
a d
Bost
wa ed
that
co ti ued
at
expa sio
could
th eate
smalle
seabi ds,
i cludi g
Sooty
Te s,
B ow
Noddies,
White
Te s
a d
Black
Noddies.
Rats
a e
capable
of
taki g
eggs
a d
chicks,
a d
thei
effects
ca
be
pa ticula ly
se ious
fo
species
that
est
o
o
close
to
the
g ou d.The
effects
could
also
each
la ge
seabi ds
i di ectly.
Red-footed
Boobies
favou
sh ubs
a d
t ees
fo
esti g,
while
Masked
Boobies
eed
elatively
ope
g ou d
fo
la di g
a d
taki g
off.
If
coco ut
palms
a d
othe
pla ts
we e
allowed
to
sp ead
ac oss
much
of
Clippe to ,
the
habitat
would
become
mo e
suitable
fo
some
species
a d
less
suitable
fo
othe s.So
the
same
isla d
that
had
o ce
demo st ated
how
quickly
seabi ds
could
ecove
afte
a
i vasive
mammal
was
emoved
was
faci g
a othe
i vasio
capable
of
eshapi g
its
bi d
commu ity.
What
Clippe to
Isla d
taught
co se vatio ists
about
i vasive
species
Clippe to ‘s
histo y
became
a
impo ta t
example
fo
co se vatio ists
wo ki g
o
isla ds
elsewhe e.
The
lesso
was
ot
simply
that
pigs
ca
ha m
seabi ds.
It
was
that
i t oduced
a imals
ca
alte
seve al
pa ts
of
a
isla d
ecosystem
at
o ce,
sometimes
p oduci g
effects
that
a e
ot
obvious
u til
a othe
species
begi s
to
disappea .
As
pe
The
U ive sity
of
Califo ia,
Ke eth
Stage ‘s
actio
o
Clippe to
was
fo
co se vatio ists
B ad
Keitt,
Be ie
Te shy
a d
Do
C oll,
who
developed
p ojects
aimed
at
emovi g
i vasive
p edato s
f om
isla ds
off
Baja
Califo ia.
Thei
wo k
eve tually
co t ibuted
to
the
c eatio
of
Isla d
Co se vatio ,
which
has
ca ied
out
e adicatio
p ojects
i volvi g
ats,
cats,
goats
a d
othe
i t oduced
a imals.Othe
isla d
p ojects
followed
a
simila
patte .
O
A acapa
Isla d,
fo
example,
the
emoval
of
ats
was
followed
by
a
fou fold
i c ease
i
Sc ipps’s
Mu elet
ests.
O
Rat
Isla d
i
the
Aleutia s,
emovi g
i vasive
ats
was
followed
by
the
etu
of
bi d
species
a d
b oade
i c eases
i
bi d
populatio s.
Clippe to ,
though,
emai s
u usually
clea
i
the
umbe s.
I
1958
the e
we e
o ly
a ou d
650
B ow
a d
Masked
Boobies
combi ed.
Afte
the
pigs
we e
emoved,
the
isla d
eve tually
suppo ted
mo e
tha
137,000
of
the
two
species.The
figu e
is
ema kable,
but
the
mo e
eveali g
pa t
of
the
sto y
is
what
sits
behi d
it.
Fifty-eight
pigs
had
bee
i t oduced
i to
a
ti y,
isolated
ecosystem.
Thei
emoval
did
ot
simply
save
bi ds
f om
bei g
eate .
It
allowed
the
la d
c abs
to
ecove ,
vegetatio
to
et eat,
coco ut
seedli gs
to
be
co t olled
a d
the
ope
esti g
habitat
favou ed
by
Masked
Boobies
to
emai
available.Fo
a
small
isla d
i
the
middle
of
the
Pacific,
that
chai
of
eve ts
became
a
emi de
of
how
much
ecological
cha ge
ca
begi
with
a
ha dful
of
a imals.