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THE PALM COCKATOO
CV: Lauraine Wilson
Amongst the many breeders in South Africa we fall into the novice category as this “hobby”
started in 2002.
I have attended and partaken in several avian courses and am currently busy with the AFA
course.
Attended the last Loro Parque Fundacion Congress and the Aves Convention in Australia
EVOLUTION – HUSBANDRY – HAND REARING
Before we get started with the real subject matter I think it would be of interest to you to
better understand the scientific classification of cockatoos the family that the Palm belongs to
The order PSITTAFORMES is made up of 3 SUPERFAMILIES which are
PSITTACOIDEA (true parrots)
STRIGOPOIDEA (large New Zealand parrots)
CACATUOIDEA
At this point we are only interested in the last of the 3 superfamilies which in turn consists of
only one family the CACATUIDAE consisting of 21 cockatoo species belonging to 7 genera
Probosciger
Palm Cockatoo
Callocephalon
Gang Gang
Nymphicus
Cockatiel
Calyptorhynchus Glossy & Red Tailed / Yellow Tailed / Short & long Billed Black
Cockatoos
Eolopus
Galah
Lophocroa
Leadbeater
Cacatua
Lesser & Medium Sulphur Crested/ Blue Eyed / Umbrella / Moluccan /
Ducorps / Goffin / Phillipine / Little Corella / Western Corella / Long
Billed Corella
Parrots are a very ancient order of birds that split from the ancestors of modern birds a very
very long time ago, perhaps in the region of between 80 and 90 million years ago during the
Cretaceous Period as Gondwana broke off to form the landforms we today know as Africa,
India, South America, Antarctica and Australia. It remains a mystery who their closest
relative is.
The first group to split off is a group of New Zealand Parrots which include the Kea and
Kakapo. The next split are the cockatoos. So this is where I want to be. Cockatoos are a well
known but highly threatened family of birds. Over half of the 21 species face extinction in the
wild - short to medium term and most species are more than well represented in aviaries
around the globe. Only 7 of the 21 species of cockatoos have been well documented in
detailed studies as they are temperate in distribution. The tropical species live in areas that are
inaccessible and often nest in trees that are either difficult to locate or access.
One such species is the
PALM COCKATOO – PROBOSCIGER ATERRIMUS ATERRIMUS
Proboscis = elongated appendage from the head of an invertebrate/vertebrate. In vertebrates
the term is used to describe an elongated snout or nose.
Aterrimus Ater is Latin for black and aterrimus is the superlative adjective for very back or
blackest.
Thus the name is a very apt description of this majestic and striking looking bird.
Their distribution covers lowland New Guinea to 1300m, the Aru Islands, the islands of
Geelvink Bay, West Papua and far northern Cape York Peninsula in Australia.
In New Guinea, palm cockatoos inhabit areas of pure rainforest and tropical savanna whereas
is Australia they inhabit savanna adjacent to rainforest. It needs to be mentioned that
obtaining accurate populations statistics on wild palm cockatoos is extremely difficult and we
only have estimations. Like other large forest birds, palm cockatoos are probably naturally
rare (Beehler 1985) and are sensitive to human disturbance.
1987 Palms were placed on CITES Appendix 1 – status least concern. In Australia the status
is currently Near Threatened meaning that they are close to qualifying for vulnerable with a
restricted range and suspected small population size. Also the western part of the York
Peninsula is being cleared for bauxite mining causing a huge contraction of their already
limited distribution range in this area. To add to their dilemma during August /September
controlled burning is exercised to control the spread of the rainforest causing the loss of
viable nests. An estimate was made in a field study of the population in the Cape York
Peninsula as having a maximum of 2600 birds (Storch 1996). The populations in West Irian
and Papua New Guinea appear to be declining. Murphy et al 2003/2005 state that “their
extremely poor breeding success may be of special concern because the long lifespan of
palm cockatoos means that low recruitment would be masked for many years by a persistent,
but ageing adult population.” Furthermore, Papua New Guinea is currently experiencing a
high rate of deforestation, possibly even one of the highest in the world. At 2008, at present
rates, the tropical rainforests in Indonesia would be logged out in 10 years and PNG 13 -16
years. 300 000ha are logged annually in PNG. Increased land clearing for development and
agricultural purposes is also having an adverse affect on palm cockatoo populations
(Igag,2002; Igag & Murphy, 2002)
In Emu,2009,109, 183-191 R Heinsohn et al. states “We consequently, suggest that, until
more detailed and longer term data are available, Palm Cockatoos be mpvedfrom the catecory
of *least concern* of the Queensland Environmental Protection Agency to *vulnerable*,
and from *least concern* on the International Union for Conservation of Nature Red List
(ICUN 2008) to *Near Threatened*.
It was widely accepted that Genus Probosciger consisted of several subspecies as follows:
PROBOSCIGER ATERRIMUS ATERRIMUS - (Gmelin 1788) Aru Islands, Cape York
and Trans Fly region of southern New Guinea
PROBOSCIGER ATERRIMUS GOLIATH
south-central New Guinea
- (Kuhl 1820) from Vogelkop throughout
PROBOSCIGER A. STENOLOPHUS - (Van Gort 1911) north and eastern New Guinea
PROBOSCIGER A. MACGILLIVRAYI - (Mathews 1912) Cape York
PROBOSCIGER A. INTERMEDIUS – (Schlegel 1861) Aru Islands
PROBOSCIGER A. ALECTO – (Temminck 1835) from the islands off the west coast off
Vogelkop
Recent in-depth studies of genetic structuring have suggested that only P.a.Goliath be
recognised as a sub-species and that all populations be classified P.a. Aterrimus. There is
much involved here this but that would take another quite some time….time which we do not
have. We have already had enough history for one day.
Palm Cockatoos are thought to be the most distantly related of the cockatoo species, being the
first to split from the group according to a molecular study done by Brown & Toft in 1999.
Murphy, 2005, states that “ a diverse array of unique physical and behavioural attributes
reflects this deep phylogenetic divergence from the other cockatoos and supports their
monospecific status”
Phylogenetic= of or relating to the evolutionary development of organisms
Monospecific= relating to or consisting of only one species
Palm cockatoos differ from other cockatoos physically with their thin crest feathers and
naked cheek patches. Furthermore, they are the only black cockatoo with solid black tails.
Additionally they line their nests with splintered twigs and the most unique behaviour
displayed is the territorial drumming by the male. I am not aware of any other bird species
making use of any form of tool.
In the wild palm cockatoos are not normally sighted in large groups and are not considered
“flock feeders” as are many of the white cockatoos. Usually you will spot a small number
between 1 and 6 individuals in tree tops. Last year in Cape York we spotted a small group of
4 individuals on the outskirts of Lockhart feasting on the fruit of the Pandanus or Screw
Palm. The locals showed us a kind of smallish seed from a tree which apparently is also
consumed. As hard as rock. Most beaches are lined with Terminalia Catappa ( bush almond /
beach almond) which the birds also feed on but were not yet in fruit. We did have the
pleasure just outside Cairns, at Yorkeys Knob see a large group of about 18 red tails feasting
on the fruit here. It was fascinating to us to observe how the birds seemed not to notice the
humans enjoying themselves underneath them barbecueing and needless to say the humans
were blissfully unaware of their presence.
The palms feeding on the fruits of the pandanus were sharing this spot with the Sulphur
Cresteds which are a common site here. We had to remain camouflaged because as soon as
the palms spotted us they would take off and tracking them in no easy task. Getting back to
their dietary requirements - they eat a lot of nuts, fruits and fruit buds of a diversified range of
flora. Quite a few of these species of flora are obtainable here in South Africa and we should
attempt to try and feed them a diet resembling that of their wild cousins. In captivity palms
are general feeders and do well on most diets. They are not big on fruit and it is necessary to
offer them fresh nuts daily. They enjoy their cooked food mixed with veggies as well as corn
on the cob, sprouts and a small amount of sunflower. It is important when weaning chicks to
offer them a varied diet that they can adapt to any new environment with one less stress
factor. Something I found interesting as I have heard of it in many other species is geophagy,
the consumption of soil which was first documented in 2006 (Symes et al) and the theory
being that “ soil is ingested to counterbalance the effects of toxic components in fruit”
In captivity the biggest challenge in breeding this species is finding pairs that are compatible.
Like with many of the cockatoos the possibility of mate aggression is a very real threat and
has led to fatalities. I would not say from heresay or personal experience that this is a
common phenomenon but it definitely exists. Palms do not have a definite breeding season
and can lay throughout the year. Both in New Guinea and Australia the breeding season is
about 8 months of the year. Of paramount importance is that wild populations have an
exceptionally low rate of reproduction. Steve Murphy’s observations suggest that palm
cockatoos breed on average every 2,2 years. There are several reasons for this extremely low
breeding rate – destruction of nest trees due to fire and wind, predation of egg and chick by
the likes of large rodents, butcherbirds, monitor lizards, scrub pythons preying on older
chicks and in Guinea the threat of human predation. All these factors contribute to the fact
that Palm Cockatoos have the lowest breeding success of any parrot species
There is a pair in SA that by now should qualify for the Guinness Book of Records. I stand to
be corrected but to my knowledge this pair has laid continuously for the past 5 years. There
are several breeding pairs here in SA but nowhere near enough yet to establish a viable future
breeding community.
In the wild their nests are usually found in hollow limbs and holes of trees, but are mainly
found in broken off trunks of trees with the opening facing skyward. Since nest cavities are
always in short supply a male palm can attend to and defend as many as 4 nests. It is not
unusual for a male to try and usurp another’s nest. It is theorised that males incubate during
the day as a competing male will attempt the takeover during daylight hours. Having larger
mandibles it is easier for the defending male to ward off the intruder. Females incubate at
night.
The nest preparation is a long and arduous task whether in the wild or captivity. But without
this there will be no breeding. A platform of sticks is constructed inside the tree hollow by
adding large splintered sticks to the hollow. The depth/height that this platform is built to
depends on the depth of the nesthole. The males do most of the nest preparation and
maintenance and the female only assists once the platform is nearly complete during the start
of the breeding season or before re-laying. We like to use either bottle brush or eucalyptus
and ensure that the birds have a steady supply at their disposal.
The reason for this nest building procedure is to protect their egg and chick from inclement
weather. They are well suited to an environment that has monsoons and so their method of
construction protects the nest from getting flooded.
What size aviary should pairs be housed in??? This question that is not easily answered nor
do I believe that there is a right or a wrong way. However, in my opinion and after seeing
them soar so gracefully high up in the sky, I do believe bigger is better. Give them the largest
aviary you have and preferably not a suspended cage. They love flying and should be
afforded this most basic right.
This species only lays one egg and the incubation time is anything from 29 to 32 days. I do
not currently know of any pairs in SA that incubate and rear their own young. I do know of a
pair that incubate their egg. Artificial incubation is relatively straight forward with incubation
temperature at 37,5 degrees and RH at 55%. Hatch time can be anything from 56 to 72 hours.
The newly hatched chick is unlike any other cockatoo chick in that is completely naked.
Weight of the newly hatched can vary from 15grams right up to 25grams. At 30 days these
chicks are still being brooded at 30degrees. Development is at a rapid pace and at 7 days the
eyes are already opening. At 40 days the pin feathers are bursting open and by day 70 flight is
attempted. Last to grow is the down which is a thick matt of grey plumes. Being a naked
chick it is brooded at a higher temperature for much longer. Initially the chick is a velvet
black turning to a grey charcoal in time as the down develops. In the wild where accurate
stats have been gathered, fledging occurred 65 -79 days after hatching. I have not found any
documented data on what parents feed their young in the wild.
Hand rearing Palms chicks is a very mythical subject and from listening globally I suspect
SA is the most successful in this field. I hear people groaning from all corners of the world
about how they are battling to raise their young and most end in disaster. On the other hand
back home here there are very few complaints. Now this is going to sound awfully sexist but
it is not meant that way. From listening to all it does appear that females are more competent
and successful in this particular niche. Palms chicks are unlike any other chick and one needs
to be in tune with them at all times. They require a high energy diet and within a month are
on only 3 feeds daily. The big challenge is weaning them and this could take anything from 8
months to 2 years. It is advisable not to rush this phase in order to produce healthy and
vibrant adults.
There are several hand rearing formulas to rear palm chicks on and all work well. Whether
you add coarse sunflower or use witches brew, your chick will thrive providing you are
consistent and dedicated. The biggest problem with young palm chicks is that the crop slows
from one feed to the next and to reverse this situation generally results in the demise of the
chick. Grabbing the first and best antibiotic is not going to solve the problem, generally it
only exacerbates the situation.
Palm Cockatoos hold a special place for many bird watchers, naturalists and aviculturists.
Often their only experience with them is in books but the impression is no less powerful and
a good example is in Parrots of the World by Joe Forshaw and Bill Cooper. The image is
inspiring and the text equally evocative:
Spectacular and lordly in both appearance and behaviour. Palm cockatoos are among the most
impressive of all parrots, especially when encountered in their natural habitat”
The Palm Cockatoo is truly a spectacular icon that encapsulates all that is wild and worth
protecting. And yet only recently have we begun to learn about their wild ways
Steve A. Murphy