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Threats to a Mixed-Species Colony of Spheniscus Penguins in Southern ChileAuthor(s): Alejandro Simeone and Roberto P. SchlatterSource: Colonial Waterbirds, Vol. 21, No. 3 (1998), pp. 418-421Published by: Waterbird SocietyStable URL: http://www.jstor.org/stable/1521654Accessed: 11-08-2014 23:36 UTC

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8/12/2019 Simeone, A., R. P. Schlatter. 1998. Threats to a mixed species colony of Spheniscus penguins in southern Chile. C

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Threats to a

Mixed-Species Colony

of

Spheniscus

Penguins

in

Southern Chile

ALEJANDRO

IMEONE1

ND ROBERTOP. SCHLATTER2

Instituto

de

Zoologia,

Universidad Austral

de

Chile. Casilla

567, Valdivia,

Chile

lInternet: csimeone@entelchile.net

2Internet: rschlatt@valdivia.uca.uach.cl

Abstract.-The

Pufiihuil

islands,

off

the coast of

Chiloe,

southern

Chile,

have the

only

known mixed

colony

of

Humboldt

(Spheniscus

humboldti)

nd

Magellanic penguins

(S.

magellanicus).

Since first

reported

in

1985,

the

colony

has

experienced

heavy

human

disturbance,

mainly

caused

by non-regulated

tourist activities and the introduction

of domestic

goats.

On the island closest to shore and most

frequently

visited

by

tourists,

28%

of

dirt burrows

have

collapsed, mainly by

accidental

trampling

and

goat activity.

In

addition,

goats

browse

the

vegetation

used

by pen-

guins

to build their nests. On

the island located farthest

offshore,

with no

goats

and fewer

tourists,

only

10%

of

dirt

burrows have

collapsed. Comparison

with

previous population

estimates

suggests

that the

colony

has declined over

the last decade. Considering the important biological value as a mixed colony of Spheniscus enguins, we propose

that these islands be

officially

protected.

Received

3

February

998,

accepted

6

May

1998.

Key

words.-Humboldt

Penguin, Magellanic Penguin,

tourism,

introduced

animals,

Chile.

Colonial

Waterbirds

21(3):

418421,

1998

In

southern South

America,

the Hum-

boldt

Penguin (Spheniscus

humboldti) IUCN

Vulnerable,

CITES

Appendix

I)

breeds on

coastal and offshore islands of the Pacific

Ocean

from Punta

Aguja

(5?S)

in

Peru to the

Pufiihuil islands (41?S) in Chile (Hays 1985;

Araya

et

al.

1996),

although

in

Per6 some

mainland

breeding

also

occurs

(Zavalaga

and Paredes

1997).

The

Magellanic Penguin

(S.

magellanicus)

(IUCN

Near

Threatened)

breeds on both the Atlantic and Pacific

coasts of South

America,

from

Cape

Horn to

42?S

on

the Atlantic side and

from

Tierra del

Fuego

to

29?S

on the Pacific

coast,

and

on

the Falkland Islands

(Williams 1995).

The two species overlap only on the Pacif-

ic

coast,

primarily

between

32?S

and

42?S.

On

Pajaro

Nifio and

Cachagua

islands

(32?S),

where two

significant

Humboldt

Penguin

colonies

occur,

only

ten to 15

pairs

of

Magellanic Penguins

have been seen to

nest

(A.

S., pers.

obs.).

On

Metalqui

island

(42?S),

where

Magellanic penguins

nest

in

large

numbers,

the Humboldt

Penguin

has

been

recently reported

to

occur,

but

breed-

ing has not been confirmed (Simeone and

Hucke-Gaete

1997).

The

present paper

describes the

only

known mixed

colony

of

Spheniscus enguins,

at the Pufiihuil

Islands,

and current

prob-

lems derived from introduced animals and

non-regulated

tourism.

STUDY

AREAAND

METHODS

The Pufiihuil islands (41?55'S, 74?02'W) are located

on the

exposed

Pacific coast of

Chiloe

Island,

in south-

ern

Chile.

The

first and

smallest island

(Island 1)

is

about 400

m

offshore. It is

covered

by bushy vegetation

including

Quila

(Chusquea

p.), Chupalla

Fascicular-

ia

bicolor),

Chup6n (Greigia sphacelata)

and

grasses

(Holcus

lanatus and

Anthoxantum

odoratum),

although

there are extensive bare surfaces. At

least six

goats

have

been seen on

this

island,

introduced

approximately

10

years ago.

The

second and

biggest

island

(Island 2)

is lo-

cated about 700

m

from the coast. It is

mainly

covered

by

Chusquea

p.,

and has a

large

amount of

H.

lanatus

and A.

odoratum.

ome E

bicolor

atches

also

occur.

Besides

penguins,

other

seabird

species

such

as

the

Kelp

Gull

(Larus

dominicanus)

and

Red-legged

Cormo-

rant

(Phalacrocorax

aimardi)

breed

at

the

islands.

Also

present

but

with

breeding

unconfirmed

are

Magellan

Cormorant

(Phalacrocorax

magellanicus),

Blue-eyed

Cor-

morant

(Phalacrocorax

triceps),

Chilean Pelican

(Peleca-

nus

thagus), Kelp

Goose

(Chloephaga hybrida)

and

Magellanic Flightless

Steamer Duck

(Tachyeresteneres).

The islands were visited

during

26-27

February

1997.

Previous

attempts

to access the islands in November

1996

andJanuary

1997

were

aborted

due

to

bad weather

conditions.

We used a

Zodiac

boat with a 15

Hp

out-

board

motor.

Each nest was

individually

checked

and

we

recorded

the number of adults and chicks at each, as well as the

size of the chicks

(according

to

plumage/down

cover-

age).

Five

penguin

nest

types

were

recognized:

a)

scrapes

covered

by

Fascicularia

bicolor,

)

scrapes

covered

by

Greigia

phacelata,

)

scrapes

covered

by

Chusquea p.,

d)

dirt

burrows

and

e)

rock crevices.

Damage

to nests

418

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8/12/2019 Simeone, A., R. P. Schlatter. 1998. Threats to a mixed species colony of Spheniscus penguins in southern Chile. C

3/5

CHILEANPENGUINCONSERVATION

(i.e.

trampling)

and

vegetation

(i.e.

browsing, burning)

attributed to introduced animals

or man was recorded.

Penguins

roosting

in flocks on intertidal

rocks

were

counted,

using

7

x

50 binoculars and a 60

x

spotting

scope.

RESULTS

During

our

visit,

we

observed

a total of

775

penguins

both inside nests

(535)

and

roosting

on rocks

(240).

We counted 561

adult

Magellanic

and

210

adult Humboldt

penguins

(ratio 3:1),

of

which

55%

and

10%

were

molting,

respectively.

Only

four

juve-

niles

were

sighted.

Six

nests had

chicks,

all of

them

belonging

to Humboldt

penguins;

no

active nests with eggs were seen.

A

total of 814 nests was recorded

for the

two

islands,

with dirt burrows

comprising

72%

and

scrapes

covered

by

Chusquea

sp.

18%

(Table

1).

The other three nest

types

ac-

counted

for

the

remaining

10%.

The

num-

ber of nests under

large

dense

aggregations

of

vegetation (particularly Chusquea p.

and

G.

sphacelata)

s

an

underestimate,

as

many

of

them were inaccessible.

Nests

activity

and nest

types

We counted a total of

285

nests

on

island

1

(Table 1).

Both

Magellanic

and Humboldt

penguins

were

seen

primarily

in

dirt bur-

rows,

which

comprised

72%

of total nests.

Only

three dirt burrows

were

active,

two con-

taining

one adult Humboldt

Penguin

with

one chick each

(30-40

days

old)

and

the oth-

er one adult

Humboldt

Penguin

with two

chicks

(+/-

30

days

old).

One nest contained

an

abandoned

egg.

A total of 529 nests was recorded on is-

land

2

(Table 1).

Both

species

of

penguins

occurred

mainly

in

dirt

burrows,

which also

comprised

72%

of the nest

types.

Three

ac-

tive

nests

(dirt burrows)

were

recorded,

each

with one adult

Humboldt

Penguin

and one

chick,

all estimated

to be 40-50

days

of

age.

Two

nests contained abandoned

eggs.

In

addition,

236

adult birds were seen

roosting

on

the shore of

the

islands,

includ-

ing

small

adjacent

rookeries: 131

Magellanic

and 105 Humboldt

penguins,

of which

7%

and

12%

were

molting,

respectively.

Only

4

juveniles

were

sighted.

Damage

to nests and

nesting

areas

Comparatively,

island

1

showed the

high-

est

proportion

of

collapsed

dirt burrows with

28% and island 2 the lowest with 10% (X2 =

28.46,

df

=

1,

P