Trial on the Use and Effectiveness of Artificial Nest Hollows for Carnaby's Cockatoo at Cataby, Western Australia

2015·4.9 MB·English

by  R E Johnstone

TRIALS ON THE USE AND EFFECTIVENESS OF
ARTIFICIAL NEST HOLLOWS FOR CARNABY’S
COCKATOO AT CATABY, WESTERN AUSTRALIA
By R.E. JOHNSTONE \ T. KIRKBY1 and M. MANNION2
department of Ornithology, Western Australian Museum,
Locked Bag 49, Welshpool DC, Western Australia 6986
2 Iluka Resources Limited
140 St Georges Terrace, Perth, Western Australia 6000
INTRODUCTION petitor species such as Galahs and
Corellas which have become
The loss of hollow-bearing trees
superabundant in many areas of
in the Western Australian
wheatbelt is one of the most the south-west region in recent
times.
important factors to overcome in
fauna conservation. Apart from Since 2000 we have been
the dwindling supply of hollows conducting ongoing experi¬
in some landscapes, obligate mentation with timber nest
hollow users must also compete boxes and poly pipe (PE pipe) or
with a number of pest and tubes (Cockatubes®) at a number
competitor species including the of sites in the south-west. Our
introduced feral European main aim was to increase nest
Honeybee (Apis mellifera) that is sites for black cockatoos with the
infesting hollows of all sizes provision of artificial nest
throughout the entire south¬ hollows, especially in areas where
west region at an increasing rate. hollows were limited and there
The use of artificial nest boxes, was extensive competition for
pipe or tube hollows and nest sites. The development of
modified nest logs has been used artificial hollows that were suit¬
successfully for the recovery of able for cockatoos, but un¬
Glossy Cockatoos (Calyptorhynchus suitable for bees and invasive
lathami) on Kangaroo Island and native competitor species viz-
for Carnaby’s Cockatoo Galahs and Corellas, was a high
(Calyptorhynchus latirostris) in parts priority as was the development
of the Western Australian of protocols for the use and
wheatbelt. Artificial nest hollows installation of these hollows. The
are not the panacea to loss of installation of timber nest boxes
natural hollows and can be and poly tubes was done in
relatively expensive to erect and conjunction with repairing sub¬
monitor. They are also subject to standard and damaged hollows
occupation by feral Honeybees as in the study area. In extreme
well as aggressive native com¬ cases this required extensive re-
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building natural hollows pre¬ strips of vegetation (e.g. along
viously used by cockatoos (i.e. Cataby and Minyulo Brooks) and
repairing walls of hollows, fixing narrow roadside verges among a
collapsed floors and removing vast area of cleared farmland. As
fallen branches that had blocked a consequence of the process of
the entrance etc.). habitat fragmentation many
Recent research at one of our wheatbelt remnants such as at
Cataby (Oliver Remnant) pro¬
monitoring sites (Cataby in the
vide significant breeding habitat
Shire of Dandaragan, 164 km
for hollow-nesting birds.
north of Perth) into the type,
size, shape and placement of
artificial nest hollows has led to a
IMPACTS OF FERAL
much better understanding of
HONEYBEES AND PROBLEM
materials and designs that are
NATIVE SPECIES
most successful for Carnaby’s
Cockatoo and what types are In this mid-western wheatbelt
best to discourage introduced region Carnaby’s Cockatoo com¬
feral and pest species from using petes for use of hollows with the
the hollows. Galah Cacatua roseicapilla, the
Most of the research reported Western Long-billed Corella
here was undertaken with (Butler’s Corella) Cacatua
funding by lluka Resources pastinator butleri, also several
Limited to satisfy part of the duck species (mainly Australian
conditions required to allow Shelduck Tadorna tadornoides
implementation of the Carnaby’s and Australian Wood Duck
Cockatoo Management Plan Chenonetta jubata) and the
presented in the Cataby Mineral introduced European Honeybee.
There has been a dramatic
Sands Project, Environmental
Protection Statement (November expansion in the distribution
2005). and status of Galahs and West¬
ern Long-billed Corellas in this
region in the past forty years (see
CATABY-DANDARAGAN Johnstone and Storr 1998). In the
LANDSCAPE
Cataby area for example both
species were listed as scarce or
In the Cataby-Dandaragan area,
absent in the late 1970s and early
as in other parts of the wheatbelt,
1980s. The massive range ex¬
there has been considerable
pansion and increase in
habitat fragmentation with the
abundance of these birds has led
clearing of most of the native
to competition for nest hollows
vegetation which has altered the
with Carnaby’s Cockatoo.
once extensive woodland land¬
scape into a fractured one, Both Galahs and Corellas begin
consisting of remnants of native breeding before the migratory
vegetation, isolated trees in Carnaby’s Cockatoo return to
paddocks, narrow streamline the breeding site and Galahs also
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maintain a continuing attach¬ to determine which designs
ment to their nest hollow (and would be suitable for Carnaby’s
sometimes other hollows nearby) Cockatoo but generally unsuit¬
throughout the non-breeding able for Galahs, Corellas and feral
season. Galahs also scar and Honeybees within the Cataby
eventually ring-bark and kill Brook area. On 7 August 2004 we
trees and, like Corellas, will also erected four artificial nest
remove eggs and chicks of other hollows within the Carnaby’s
species from hollows. Cockatoo breeding area of Oliver
Remnant (an area of mostly
Our study site at Cataby also
clearly highlighted the enor¬ Wandoo Eucalyptus wandoo
woodland) along Cataby Brook.
mous problem of the feral
European Honeybees taking over Two of these (nest numbers 357
and 360) are large PE, top entry
hollows in this region. We
poly pipe hollows (see details
located over 200 feral beehives in
a narrow 3 km stretch of below) and both were erected in
the main trunks of large
Wandoo woodland along the
Wandoo trees with burnt out
Cataby Brook. Many of these are
in hollows that have been pre¬ tops (chimney stack type trees). A
large wooden, top entry nest box
viously used by Carnaby’s
(nest number 358) was erected
Cockatoo and other birds. For
8.3 m up in a large Marri
impact of feral European Honey¬
bees on black cockatoos see Corymbia calophylla growing at
the edge of Cataby Brook and a
Johnstone and Kirkby (2007).
smaller wooden side entry box
The 2004 Cataby survey located
(nest number 359) was erected 7
24 hollows used by Carnaby’s
m up in a Wandoo also at the
Cockatoo, 84 used by Galahs, 37
edge of Cataby Brook.
used by Long-billed Corellas and
In August 2005 nest box 359 that
8 used by ducks. This site was
clearly very suitable to assess the had been quickly taken over by
Galahs (see below) was removed,
impacts on Carnaby’s Cockatoo
repaired and altered into a top
from competitors, especially
entry box and in 2006 was re¬
Galahs and Corellas, to look at
erected (as nest number 069) 7 m
hollow decline and to trial
up in a Wandoo.
artificial nest hollows to see if it
was possible to reduce com¬ In September 2007 we erected a
petition for nest hollows. third PE nest pipe (nest number
441) in Wandoo (near Oliver’s
Homestead) giving a total of five
CATABY STUDY
artificial hollows that have been
In 2004 we began to trial a small monitored each year to the
number of artificial nest hollows present 2014.
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DETAILS OF ARTIFICIAL
HOLLOWS
Two wooden nest boxes were
trialled and are described below.
A large wooden box nest 358
(Figure 1) made with exterior
grade plywood and measuring
750 mm high-deep, with a
sloping hardwood spout 320 mm
high at back to 50 mm at front
(see figure 1) giving a total depth
of over 800 mm, with circular 170
mm diameter spout entrance on
a hinged lid, rectangular box 400
x 300 mm. All inside walls were
lined with 10 mm square heavy
gauge mesh to prevent birds
chewing through the sides and
allows birds to climb to entrance.
All outside corners are protected
Figure 2. Nest 069 (formerly 359) -
small wooden box
by 20 x 20 mm aluminium angle
which prevents destruction from
outside. A small observation
panel is provided on one side
with a galvanised plate held in
position with a Tek screw. The
boxes were painted with Gripset,
a bitumen rubber sealant
(adhesive coating, water-based,
non-flammable, non-toxic, free
of solvents and dangerous fumes,
and UV resistant) including the
inside floor to help with
waterproofing.
A small wooden box nest 359
(Figure 2) constructed from
exterior grade plywood with a
hardwood spout side entry. The
internal chamber size is 650 mm
Figure 1. Nest 358 - large wooden box high-deep, square 240 x 240 mm,
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with floor space 350 mm These PE tubes were specifically
diagonally, and side spout with designed by R. E. Johnstone and
200 mm diameter entrance. The T. Kirkby for black cockatoos
interior wall is lined with 10 mm based on measurements of
square galvanised mesh and hundreds of natural hollows
outside corners protected by 20 x used by all three species of black
20 aluminium angle. A small cockatoo in the south-west.
observation panel is provided on
PE industrial pipe is used by
one side with a galvanised plate
mining companies with off-cuts
held in position with a screw.
and old sections of pipe being
The wooden base was sprayed
readily available. The length of
with Citronella oil to deter feral
pipes used ranged from 0.8-1.2 m,
Honeybees. the external diameter ranged
Three Medium Density Polyethy¬ from 350-400 mm and the
lene (MDPE) or PE tubes (poly internal diameter 300-350 mm.
pipe hollows or Cockatubes®), The PE tube orientation is for
two large one slightly smaller vertical top entry as all black
were also trialled and are cockatoos back into hollows and
described below (see Figures 3, 4 this makes the tubes attractive
and 5). for Carnaby’s Cockatoos, but
I
Figure 3. A: Nest 357 - PE pipe. B: Nest with breeding pair.
254
Figure 4. Nest 360 - PE pipe Figure 5. Nest 441 - PE pipe
unattractive to feral Honeybees the pipe with galvanised bolts.
and competitor species i.e. Galahs These posts were left extending
and Corellas that prefer dark beyond the top of the pipe in
hollows. order to provide evidence of
hollow use i.e. fresh chewing
Internal access is provided by a
during the breeding season.
galvanised weldmesh or other
heavy wire mesh internal ladder The floor was made of heavy
100 mm wide (about 20-40 mm duty stainless steel, treated metal,
squares) or heavy chain bolted galvanised mesh or thick hard¬
through the pipe with galvanised
wood timber, shaped to fit
gutter bolts.
internally with sharp or rough
At least two sacrificial chewing edges curled inwards and fixed
posts ca. 70 x 50 mm of hard¬ with galvanised or stainless steel
wood or sections of hardwood Tek® screws. Holes were drilled
e.g. Wandoo, Marri or Jarrah etc. around the base for water drain¬
are fixed to the sides of the age. The floor space was filled to
internal ladder. The timber was about 150 mm with wood chips
pre-drilled and attached through to create a dry egg mat.
255
INSTALLATION OF ARTIFICIAL petition for hollows from feral
HOLLOWS Honeybees, Galahs and Western
Long-billed Corellas (Butler’s
Both wooden boxes and tubes
Corella) and where many pairs
were attached to trees with
were using poor quality or
brackets, galvanised chain or
substandard natural hollows i.e.
simply bolted or screwed to tree
shallow open hollows subject to
(if in burnt out trunk) and
predation and flooding etc.
erected in vertical or near
The large wooden box, nest 358
vertical position.
(Figure 1), was erected in a large
Where possible, hollows were
Marri (containing no hollows) at
erected facing away from
the edge of the Oliver Remnant
prevailing weather and at a
and about 100 m from the near¬
similar height to natural nests.
est Carnaby’s Cockatoo nest but
Although these artificial nest
adjacent to several feral Honey¬
boxes and tubes are heavy, they
bee hives and Corella nests.
can be lifted into position using
a rope and pulley by one person The small side entry wooden box,
and held in place while being nest 359 (Figure 2), was erected in
a tall Wandoo (with no hollows)
attached. A 4WD vehicle or
and between trees with an active
‘elevated work platform’ could
Galah nest, a Corella nest and a
also be used to position the
hollow used by Carnaby’s
hollow.
Cockatoo.
The three PE tubes were spread
POSITIONING OF ARTIFICIAL
through the breeding habitat
HOLLOWS
and all are close to feral
At Cataby the hollows were Honeybee colonies.
positioned at specific sites in One large PE tube, nest 357
order for us to study not only (Figure 3a), was placed inside a
the uptake of the hollows, but burnt out main trunk of a
also to look at competition with Wandoo adjacent to another tree
other species and to determine that contained a natural nest
the use and success rate of hollow that was being vigorously
different hollow types over a fought over by pairs of Corellas
number of breeding seasons. We and Carnaby’s Cockatoos. It is
were also interested in the noteworthy that by inserting the
longevity of the different nests tube into the burnt tree trunk of
including the sacrificial posts, this tree, which is close to a
walls and floors of the hollows. roadhouse and a rest area often
All the artificial hollows were visited by general public, it
placed within the Oliver rem¬ became relatively inconspicuous.
nant patch of Wandoo wood¬ A second large PE tube, nest 360
land in areas where Carnaby’s (Figure 4), erected in another
Cockatoo undergo high com¬ burnt out main trunk of a
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Wandoo was close to natural Carnaby’s Cockatoo, but by 15
hollows in adjacent trees that November the box had again
were being fought over by both been taken over by an Australian
Corellas and Galahs. Shelduck and contained five
addled Shelduck eggs and an
A third slightly smaller PE tube,
addled Carnaby’s Cockatoo egg
nest 441 (Figure 5), was erected
near a small chimney-type buried under duck eggs and
down.
hollow in a dead Wandoo (near
Oliver’s homestead) that had In the 2008-09 breeding season
been used by Carnaby’s Cockatoo Carnaby’s Cockatoo were successful
since the 1950s and in more at fledging a chick from this box.
recent times had been used
In the 2009-10 breeding season a
intermittently by Carnaby’s
chick was successfully fledged.
Cockatoo and Corellas both with
In the 2010-11 breeding season
little success.
two chicks were successfully
fledged.
HOLLOW USE In the 2011-12 breeding season
the nest box was unused.
Nest 358 - large wooden box
In the 2012-13 breeding season a
In the first breeding season
chick was successfully fledged.
(2004-05) the large wooden box,
In the 2013-14 breeding season
nest 358 (Figure 1), was quickly
the nest was unsuccessful. A
taken over by a pair of Carnaby’s
female was flushed from the nest
Cockatoo and they successfully
on 21 September, also on the 5
fledged a chick.
October and on the 19 October
In the 2005-06 season the nest
2013, so no doubt eggs were laid,
was unsuccessful. On 3 Sep¬
but were unsuccessful.
tember 2005 the nest contained
5 eggs of the Australian Shelduck Nest 069 (formerly Nest 359) small
that were removed, a single wooden box
Carnaby’s Cockatoo egg on 17
The small wooden box, Nest 359,
September and 9 October 2005,
erected in August 2004 was
but this egg was addled and
quickly taken over by Galahs
rotten by 24 October and
(prospecting it within hours of it
although a female Cockatoo was
being erected). On 20 August
observed in the nest in Novem¬
2005 a female Galah was flushed
ber and December no further
from the box that contained a
eggs were laid.
single egg and the base of the box
In the 2006-07 breeding season a had been completely destroyed
chick was successfully fledged. by the Galahs chewing the
In the 2007-08 breeding season timber from both inside and out.
the nest was unsuccessful. In It was removed in 2005, repaired
September-October 2007, this and altered into a top entry box
nest contained a female (lid removed) making it more
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suitable for Carnaby’s Cockatoo Cockatoo was observed fighting
then re-numbered 069 and off Corellas in November 2009.
erected 7 m up in a tall Wandoo
In the 2010-11 breeding season it
about 100 m away in 2006. was unsuccessful. A female
Nest box 069 (the altered 359) Carnaby’s Cockatoo was flushed
was used successfully by to the top entrance of the box on
Carnaby’s Cockatoo in the 2006- 6 September 2010 and on 24
07 breeding season with the September 2010, but the nest box
female using the top entry rather contained two broken eggshells
than the side spout. At only 650 on 9 October 2010. The eggs were
mm deep and 240 mm square, probably broken by Corellas.
this is one of the smallest In the 2011-12 breeding season it
hollows we have recorded used was again unsuccessful due to
by Carnaby’s Cockatoo. competition with Grey Teal
(Anas gracilis). A pair of Carnaby’s
In the 2007-08 breeding season it
Cockatoos certainly attempted
was unsuccessful. It contained a
to breed in the box that season. A
female Carnaby’s Cockatoo on 22
male was observed on top of the
September 2007, but by 19
box on 2 November 2011, a
October it contained a Corella
female flushed from the box on
perched at entrance and
18 November, but by 3 December
Carnaby’s Cockatoo eggshells in
the two cockatoo eggs were
the box.
addled and had been covered by
In the 2008-09 breeding season Grey Teal feather down and eggs.
it was again unsuccessful due to The nest box had obviously been
disturbance by Corellas or taken over by the Grey Teal after
Galahs. A female Carnaby’s the Carnaby’s Cockatoo had laid
Cockatoo was flushed from the eggs.
nest on the 25 September and 10
In the 2012-13 breeding season it
October 2008 and a pair observed
was again unsuccessful. A female
on the box on 18 November with
was flushed to top of box on 6
the female fighting off Corellas,
October 2012, 20 October 2012,
and a female was flushed to the
and 3 November 2012. The nest
top entrance of the box again on
contained a downy chick on 17
12 December, but by 29 December
November, a pin-feathered chick
the nest was empty except for
on 1 December 2012, a large
feathers of Carnaby’s Cockatoo
feathered chick on 22 December
and feathers of Corella and
2012, but a dead fully feathered
Galah and we believe that the
chick (ready to fledge) on 12
cockatoo eggs were destroyed by
January 2013. This chick probably
the former.
died due to a week of heat-wave
In 2009-10 breeding season it was conditions. A number of other
unsuccessful again probably due chicks in natural hollows at
to competition/predation by Cataby were lost during the same
Corellas. A female Carnaby’s period.
258
In the 2013-14 breeding season a September 2013 and a male was
chick was successfully fledged. perched near the nest on 2
November 2013, but the nest
Since being altered it has been
used successfully by Carnaby’s contained only egg shell remains.
Cockatoo in 2 out of 8 breeding Overall it has been successful (i.e.
seasons and has lost eggs and fledged a chick) in six out of ten
chicks in other years due to breeding seasons.
various reasons, but mainly
through competition for the
Nest 360 - PE pipe
hollow from Corellas, Galahs and
Nest 360 (Figure 4) was unsuc¬
small ducks which is reflected in
cessful in the 2004-05 breeding
the low breeding success rate.
season. An almost fledged chick
Our plan is to erect a PE tube
in this nest was probably taken
near this nest for comparison of
by a cat judging from fur and
breeding success.
feathers near the tree.
In the 2005-06 breeding season
Nest 357 - PE pipe
it was also unsuccessful. On 20
The PE pipe nest 357 (Figure 3a)
August 2005 a pair of Corellas
was not used in the 2004-05
that had been prospecting this
breeding season.
nest had burrowed under the
In the 2005-06 breeding season base of the nest pipe into soft
it was unsuccessful. A female wood debris and a plug of
Carnaby’s Cockatoo was flushed termite workings, creating a
from the nest on 20 August 2005; tunnel over 30 cm long and by 3
it contained two eggs on 3 September 2005 had laid eggs in
September and 17 September the tunnel. The nest tube
2005, but only the remains of contained a female Carnaby’s
hatched egg shells with both Cockatoo incubating 2 eggs on
hatchlings missing on 9 October 24 October 2005 but these eggs
and egg shell found under the were predated on (probably by
tree on 24 October 2005. the Corellas) by 12 November. It
In the 2006-07 breeding season it is noteworthy that the Corellas
was unused, however, it was found the nest tube unattractive
regularly visited judging from and burrowed under the pipe to
the extensive chewing on the create a dark nest cavity, but
internal sacrificial posts. apparently still competed with
the pair of Carnaby’s Cockatoos
In the six 2007-08, 2008-09,
that arrived much later to use
2009-10, 2010-11, 2011-12 and
the nest. The Corella tunnel or
2012-13 breeding seasons it was
burrow was filled in 2005.
successful fledging a single chick
each year. In the 2006-07 breeding season a
chick fledged successfully.
In the 2013-14 breeding season it
was unsuccessful. A female was In the 2007-08 breeding season it
flushed from this nest on 21 was again unsuccessful. It
259