Missing:
Contributions
to
Zoology,
SPB Academic
of the endemic
Conservation
Javan
70
161-173
(3)
Publishing bv,
(2001)
The
Hague
hawk-eagle Spizaetus bartelsi
Stresemann, 1924 (Aves: Falconiformes): density, age-structure and numbers
S.+(Bas)
Balen
van
Nature
'Tropica!
Bornsesteeg 69, ics,
Vincent ¹,
Conservation
6708 PD
²
& Resit Sözer
Nijman ²
population
and
Vertebrate
Ecology
The Netherlands.
Wageningen,
Zoological Museum, University of Amsterdam,
forest
Key-words:: birds-of-prey, raptor,
Group,
Institute for
P.O. Box 94766,
fragmentation, Java,
The endemic
hawk-eagle Spizaetus bartelsi
Javan
because
is considered threatened with extinction
and
University,
Ecosystem Dynam-
1090 GT Amsterdam,
The Netherlands
Indonesia
Abstract
161
Introduction
161
Material
small
its habitat
size and
population the
on
fragmentation of
densely populated island of Java,
Indonesia. Like many other
tropical forest raptors
little is known about many of its meters. Research
in
Agricultural
Biodiversity
Contents
Abstract
of its
Wageningen
2
order
to
carried
was
the
assess
out
status
population
from 1980
of this
2000
Its
species.
Data
162 162
area
acquisition
Determination
164
of
164
densitly
165
Age-structure
para-
to
and methods
Study
Estimate
of
population
numbers
165
Statistical analysis
166
Results
presence
both
wet
was
confirmed
dry climatic
and
calculated
were
comparison these
with
zones.
published
may differ
island
in
Home range sizes
166
Distribution
Discussion
estimates suggests that
Density
significantly
and
day, and
with
short
a
long
dry
in
are
survey
between
areas.
dry
is
for all
been
captive
1.3. An
1:
large
timate that there account of
for
a
gestions more
for
insight
world
related habitat
age
servation,
including
gazettment of
more
new
non
lead
numbers
a
us
which
just short
obtaining
recruitment and and for strict
reserves.
and
improved
conservation
170
Acknowledgements
171
References
171
Appendix
I
172
Introduction
dento es-
number of sug-
aimed at
169
for further research
quality
remaining pairs, of
168
structure
adult
working
quality,
We make
preferences,
a
hawk-eagles have
population
dispersal,
per
areas
with
areas
of habitat
conservative
habitat
further research on
to
birds, the adult:
137-188
are
total
thousand birds.
a
and
a
to
167 168
and
Population
En-
field-observations,
assessment
and
sity differentiated
on
where Javan
areas
recorded,
compared
Based
season.
higher in
significantly
season
museum skins and
ratio
the order of 0.1-0.9 birds
were
166 size
²,
Suggestions counter rates
density
Age-composition and population
and
12-36 km
range between
to
the
throughout
improved
agecon-
law enforcement
The Sundaic the
hottest
area
region has been identified
biodiversity
that has lost
vegetation and
is
a
the
than
fish
(Myers
fragmentation
the island of Java, Indonesia, cover
has
in
one
of an
plant
original
turned the
and
ah, 2000).
et
region,
is most ancient
with less than
remaining under forest.
destruction of the Java
rich
different parts of the Sundaic
deforestation and
of land
as
earth, i.e.
high proportion of its primary
disproportional
vertebrates other
Among
hotspots
on
lowland
on
10%
The overall
vegetation
habitat of Java’s
on
rainforest
162
S.
into
specialists
quently,
fragmented of
patches
varying
endangered
critically
or
(Hilton-Taylor 2000; Collar these is a
the Javan
forest
tropical Hardly
endemic
eagle
parameters, demography
tropical forest raptors (Thiollay, to
in
species
species
few
1994). Compared
offspring often have prolonged 1994). Given the
destruction it is
1997;
ah 2001),
et
cluding birds of
On account of small for
a
ing
IUCN
to
threat
has been
recognised
Given the
relatively the
order for
low number of
and in order to allow essential
lation in
to
have
such
different
habitats, like
Unfortunately,
raptors, these data the relevant data ies and a new
and
a
sults latest
we
present
assessment
Birds (Collar
et
Stuart,
and
population
lacking.
conducted to
to
scant
on
in
be made it is
popu-
numbers.
tropical
In order to a
forest obtain
number of stud-
2000. Here on
we
present
original research
published
data. The
re-
study have been used in the
of the Red
ah, 2001).
major
the
with
ah,
et
100,000 km
montane)
Data Book for Asian
2
Tectona
estimated total
forest (lowland, 17th
in the
present
et
in the 2nd to 4th century
An
1996).
com-
loss of which may have
introduction of teak
of natural
was
probably
was
forest (MacKinnon
by tropical
the first
1982),
(Whitten
of
area
hill
and
(Smiet,
century
2 1990). About hundred years ago 40,000 km
was
left of this, but this further decreased to about 15,000 km
2
in
the
years
is
to
about 10,000 km 2
land, cash
further
century,
during the past
original vegetation and
largely replaced by cities
agricultural
crop
natural forest
10%
areas
of the
54% of the
villages, roads,
The
latter
natural
forest,
2% of the
forest type
is
along
easternmost part
forests
remain:
19% of the
original
lowland forest
1990; Whitten
1988; Smiet,
found scattered
leaving the
brasiliensis),
original
only
Pinus
habitat islands. Overall, less
as
mountain
hill forest, and
Balen,
Hevea
50
cover
plantations (e.g. cof-
Coffea spp), forest plantations (teak, pine
merkusii, rubber
the
The
(Smiet, 1992).
now
fee
half of the 20th
first
decreasing
now
the
et
almost
southern
ah,
exclusively and
coast
of the island of Java.
generalised
land
use
(van
1996).
1
Fig.
of the
cover
in
is-
land of Java.
given
eagles,
number of basic
and
pletely ah,
island of Java
covered
presents the
age-structure, densities
of status based
review of the of the
a
as
1980 surveys from
appraisal
surviving
for many other are
has
bird trade
subsequent monitoring,
insight in
parameters,
and
dependence areas
status assessment
accurate
an
&
illegal
large continuous forest
expected
disappear
ah, 2001).
et
the
Originally,
than
(Collar
hawk-eagle’s
Javan
in-
additional threat (Sozer
an
1995; Collar
Nijman,
Owens
hawk-eagle
the
recently as
to
to
endangered accord-
as
categories
more
prone
fragmentation
Javan
long time been classed
re-
ah 2000).
et
habitat
the
size
population
1988) whereas
and
severe
in
top-predators,
be the first prey, may
1988; Davies
(Terborgh,
animal
Bennett &
and
and
of forest
rate
especially
are
1997;
(McKinney,
Fagan
year,
fecundity and occurring
stricted ranges (endemics) extinction
larger
produce
widely believed that large
with low
species,
the
fledgling periods
alarming
area
grandis by early Hindus
not breed every
may
Study
numbers of
typically
year,
of Javan hawk-eagles
Material and methods
occurred
long-lived, hold large stable
throughout the
offspring and
(Clark,
Among bartelsi,
temperate regions, especially
probably
are
territories
Conservation
-
population
on
population
or
Sozer
endangered
2001).
available
are
classed
the island of Java.
to
& R.
Subse-
are
hawk-eagle Spizaetus
data
any
et al.
Nijman
of
system
sizes.
rainforest vertebrates
some ten
either
as
highly
a
forest
numerous
V.
Balen,
van
The
climate
longitudinal
on
Java differs
Java and the north coast have season,
greatly along the
axis of the island. The eastern part of
while in the
nowhere marked. In
western
a
pronounced
half it is
general, the
wettest
tion types (mixed
lowland and hill
ever-wet montane
forest) only
at
least 30
secutive
vegeta-
rainforest and
occur
in
areas
rainy days during the driest four
months
Lammertse,
(van
Steenis
dry
weak and
and
with con-
Schippers-
1965), and hence is mostly
found in
the western and central part of Java. Rain forest is also found east in
throughout
the otherwise
the wet “islands”
cloud stowage
on
seasonally dry
which arise
as
a
result of
the southern and south-eastern
slopes of the higher mountains (van Steenis, 1972). In est
the drier
replace
areas
moist
rainforest.
forest and deciduous for-
Contributions
to
Zoology,
70 (3)
-
2001
163
1996). al. et
Whiten (after
Madura and
Bali
Java, on
use
land
Genralised I.
Fig.
S.
164
Data
V.
Balen,
van
& R. Sozer
Nijman
Conservation
-
maintained, allowing observations
acquisition
comprehensive
Tropical
forest
observe.
Thiollay (1985) estimated
he
age
eagles
observed
of
only
the
Yamazaki pcrs. of the
ence
scanning hill
that
area
edge
or
aver-
does
fly
not
from
and
opening)
to
and
soar
all
(T.
by
point (i.c., the
searching
be assessed
calls heard
by
points and along
tage
Observations
general study specialised
small forest
the
over
surveys
van-
and
Java
on
species
assessed in
was
2 (50
areas
Halimun,
Murio,
Gazetteer) the
not
1994).
density)
dry
nine
Kulon,
Kawi-Kelud,
breeding
between encounter rate with
of the
Lebakharjo-Bantur, see
attempt
derivative for
of
al.
et
likely related
an
length
contiguous
Meyburg
relationship
in the
ing
occupy
(77%)
(1982)
was
juveniles and immatures do
(cf.
forest and in
eagles (as
the
reported
were
hold territories
plored
roads
near
these estimates
areas
1300(95%)
10493
et
on
study
1365
3163
Java
low
the
in Pasir
breeding male
effort.
area
Central
areas
relative
Remaining
West Java
through
mapped the locali-
sity is calculated by assuming that all adult eagles
704
forest
a
we
under-estimates.
breeding activities
sev-
inside natural for-
to and
sum-
presented
data from other researchers.
were
home ranges
remain-
were
(see Table I). While travelling (almost exclu-
sively
f
over
shared amongst
were
surveying
Java
cover
typically
weeks.
% of which
hawk-eagle.
areas
of areas
majority
least twice, while surveys
eral
est
forest
investigated
brief
a
are
polygon method. Given the limof the
certainly
compiled
we
a
Java. Home range size
convex
territories,
In
data
new
density
observed
accessibility
occur
of the Javan
occurrence
al. (1999);
Java, and another adult
Asri, Central
cal
expected
et
is
of density
we
West
2 able forest blocks (>50 km ) with known histori-
or
Balen
additional
In order to estimate
are
inside the forest.
transects
forest birds
The presence of the merous
from both these
are
also
made in the framework of
were
on
Presence could
display.
van
and
mary
scrutinised
were
the pres-
between 09.00 and 12.00 hours when the birds
expected
presented by
1898-1999
20%
assessed
was
vantage
a
from
95%
on
at
1995). Therefore
hawk-eagles
made. A
to be
in which all records of Javan
account
here.
(subtropi-
days with favourable weather
on
canopy
on
to
day while
per
nipalenis spends
hawk-eagle
Javan
top, forest
sky and
S.
it
comm.,
large
a
raptor
inside the forest, and
observed
days
difficult
notoriously
one
hawk-eagle
daytime perched
of
are
inside the rainforest. The
walking slowly cal mountain
of Javan hawk-eagles
Contributions to
under
(3)
the number of
by
2001
~
weather conditions.
good
measured
70
Zoology,
Dry
165
season
was
the
rainy days during
1991), which
(Newton
but also
quality,
persecution
four driest consecutive months of the year and taken
hawk
from
lowing parameters:
Steenis and
van
Schippers-Lammertse (1965).
eagles
Altitude.
eagle (Nijman extrapolate observations
to
tion of the total wild age structure is
cipal the
data
wild;
required.
sources
2)
population
were
Netherlands;
Bogor,
the wild and held in
collections
Mini
et
al.
hawk-eagle
by plumage patterns and
Javan
banding patterns
from
dark
very
as
is
brown,
in
lull
Javan
1995), fifth
at
but
year,
The
an
most
almost
tion
as
in other
classed
-
In
(1998).
as
black
are
com-
it
changes
in
downy
golden yellow in to
Nijman,
eagle species of comparable pers. comm.,
of the
observed in
c. one
wild
1990).
popula-
the field
year), immature (c.
five years) and adult (six
to
c.
20
as
est
breeding pairs
inhabited
of established
limited
and the
pairs
the
Steenis and
area.
by the availability
of
was
in number
Raptor numbers nest
sites
with
areas
mixed low-
least 30
at
types
of Javan
Schippers-Lammertse,
known
are
for-
rainy
contain
to
the
1965);
highest
hawk-eagle (Meyburg
ah,
et
these
densities
1989,
see
results). The
Ruggedness.
ruggedness of the
area
is
an
important feature for the
Javan
has been characterised
slope specialist (Wells,
1985). Tall forest ferred
to
forests
on
to survive
than in
area
an
size (cf Harris, is
significantly Balen
(van
The
ing.
size
from land scale
1:
figures
use
250
maps
are
of the
of
correlated
pre-
to
provided by
same
area
size
eagles
susceptible
fragments
more
forest
occurrence
Furthermore,
more
forest
one
frequency
2000). are
it
to
in
hunt-
measured
was
RePPProT (1990:
000). By comparing these figures with in
given
our
hawk-eagles
positively
of
be
large circular-shaped
1984), and
(e.g., MacKinnon and
a
to
as
plains (see results).
irregularly shaped
forest
fragmented
hawk-eagle
slopes is believed
Javan
in
ah,
et
as
flat
on
Fragmentation. likely
own
conservation et
management
1982; Whitten
ah,
data from the
tative estimate
The total
geographic
density expressed
per
in
occur
field,
we
et
ah,
made
a
plans 1996) quali-
of the available habitat.
population of
was
calculated
Javan
are
and prey
where B A
block; and H
=
=
=
hawk-eagles
in
n
forest
by
j_j
on
—
days during the four driest consecutive months (van
S
area
expected
lower elevations (see
at
one
years).
per forest
calculated by extrapolation based area
only
—
ofpopulation numbers
The number of
the Javan Hawk-
as
Climate. The richest forest types
blocks
Estimate
A
1996).
is therefore
2000)
densities
higher
ah,
land and hill rainforest and montane everwct
this
breeding only in its
starts
eagles
juvenile (fledgling -
Meyburg
hawk-eagle is believed
structure
age
recog-
juveniles into light
to
1979; Yamazaki
modelling we
in
subadults
likely
life
reach
et
results).
private
various
of four years (Sozer and age
size (Newton, For
Sozcr
Park,
markets
readily
additional clue
grey and lemon adults.
be
gar-
considered adult when
chicks, dark blue bluish-grey
mature
The
belly and wings
on
an
are
bird
described in
Nijman and
hawk-eagles
plete. Eye-colour
local
can
in
freshly cap-
zoological
Indonesia),
on
1989-2000).
period
the
Leiden,
Indonesia Indah Bird
encountered
Javan
in
(1989)
paper the
or
the
(during
nised
in
in
(Na-
museums
History
Surabaya Zoo, Taman Safari
stages
1)
to
prin-
Zoologicum Bogoriense
Museum
(Taman
of
observations
Indonesia); and 3) live eagles
tured from dens
this, three
stored in
specimens
tional Museum of Natural
estima-
an
assessment
an
To model
used:
to
ah,
et
Javan
by the fol-
tropical rainforest
(Whitten
relatively unspecialised raptor
structure
In order
of the
Productivity
by habitat
Density of
etc.
therefore determined
are
decreases with altitude
Age
determined
are
Number of
(equation
breeding pairs
per
1)
forest
the available habitat in each forest block;
the
density of pairs occurring in Habitat
quality type j. Habitat quality type is the median score
of the above described parameters
( climate
,
166
S.
van
ruggedness and fragmentation) each of which given
a
For be
score
less
areas
small
too
between 1
to
hawk-eagle
than
(‘ good ’) c.
50
km
area
error
Hapsoro
Mt
-
and Mt
in
Linsley
decades other
two
1999),
litt.
West
and Mt
Sawal
Cupu-
in Central
Ungaran and
1994),
analysis
Appendix
see
Mt
tributed
or
are
ordered
increase
to
as
data collected
most
the
non-parametric
dry
season
U test.
Fortesting
used
were
areas
differing
compared
were
an
with
independent, and whether there vey
effort,
a
in
p
