Home > Forums & Experts > Parrot Bloggers > Parrot Blogger - Brent Barrett

Parroting aroung - Mountain to the Sea

by Brent Barrett

Globally parrots occupy vastly diverse habitats, obviously not in the northern continents but certainly in the southern regions. In Ushaia there is a parrot that lives amongst the valleys that bisect the southern tip of the Andies. In the Amazon birds swelter under blazing suns. Gang-gangs cockatoos nibble seed cones in snow clad trees on the Blue Mountains range and Kakapo stumble through muddy ferns on the temporal rain forest floor. We tend to think of parrots and trees going hand in hand. Even in the deserts of central Australia where incredible numbers of parrots congregate around dying water holes we still see them roosting in trees. I have seen flocks of Budgerigars fill a dead tree so that it looked as if it has sprung new lush yellow and greed leaves. Then suddenly the flock erupted into the air as if a tornado had hit and there remained the lifeless tree again. I do know of one bird that seems to break the parrot/tree rule, a creature that is amongst the most intelligent birds on earth. With a full complement of problem solving skills this parrot has learned to adapt to all levels of elevation and is considered to be the worlds only truly alpine parrot. I am talking about the Kea (Nestor notabilis) New Zealand's Mountain Parrot. It is this creature (and the occasional cycle tour of Australia's Northern Territory and a brief stint with Western Australia's Ground Parrot) that has meant that I have not blogged in over 1.5yrs. But it is this creature that so challenges me that I can't ever seem to get the upper hand. I find it hard to speak with any authority about its natural behaviour despite spending endless days tracking it through the bush and locating and monitoring its nests.

Posted by Brent Barrett on 03/09 at 01:13 PM

Is time running out for Ground Parrots

by Brent Barrett

There is no doubt that the fire regime empoyed during land clearing and grazing times in Western Australia had a huge impact on the availability of habitat for Western Ground Parrots. The complex heath that WGP's occupy is typically devoid of large trees and therefore easy to clear with few modifications for farming. Sadly the soil is very shallow and infertile and the pasture soon turns to dust, followed by flooding and soil erosion and eventially salt damage when the water table rises and carries with it the salt resulting from decomposed 4 billion year old rock. The chance for this land to return to suitable WGP habitat is very low. Due to the salt damage or salinity no replanting campain can improve the land. It is for this reason that the delicate habitat that remains must be protected at all costs. However, when fire is a major force in the environment and considered natural and essential for plant germination, you have a very difficult situation. Mosaic and patchy burn patterns allow the plants to germinate and parent stock of species to survive in nearby unburnt habitat. The difficulty for WGP's is that if the vegetation is less than 5 years old they cannot nest of roost in the area. If it is more than 18 years old then the major food plants have been replaced by larger woody species. Such a problem may not be solved in a hurry and requires a continued effort over many years. At the begining of the project I started in Western Australia we had no idea of the habitat requirements of WGP's and so we first had to set about asking the parrot "what do you actually want?". The answer to that was three years coming and still the WGP is trying to tell us, calling every evening and morning. But are we listening hard enough?

The author apologises for the extented pause between entries but just started a new exciting job with mountain parrots and hasen't sat down in 3 months.

Posted by Brent Barrett on 12/23 at 01:49 AM

Parrot response to environmental factors - Fire

by Brent Barrett

Let us explore further the response of parrot populations to environmental factors such as climate (incl. change), predation, vegetation (food) and habitat loss. Already we know that Kakapo require a very specific event to initiate breeding, but there are populations of parrots with much more complex requirements. These relate to a vector of change that is neither predictable nor controllable. I'm talking about fire or more specifically bush-wildfire. Fire is an essential part of the Australian ecosystem and is a very complex beast. Many plants in the Australian outback need the presence of fire in order to germinate, often these plants require the heat to open their seed pods. Typically these trees have a very thick bark layer which can withstand the searing heat and, surprisingly, accelerate fire by emitting flammable oils from their crown (particularly gum trees). Small shrubs and orchids grow from root stock that is safely deposited in the ground ready to sprout once the fire has destroyed all shade plants.

As such it is expected that at least some parrots have learned to take advantage of this post-fire growth. One such specialist is the Western Ground Parrot (Pezoporus wallicus flaviventrs). A resident of the arid land that occupies a narrow strip on the south coast of Western Australia, particularly Cape Arid and Fitzgerald River National Parks. You can read all about this bird in PsittaScene Volume 20 #3 where it has pride and place on the front cover, You will be hearing more about our friend the Western Ground Parrot in the future because they are a particular favorite of mine. However for now we will discuss what has influenced fire events over Australia's history.

Historically fire were driven by the climate and other environmental factors such as vegetation-age and land topography. Fire was typically initiated by lightning strike which is a common event in October on the south-coast. These fires where patchy and formed a mozaic of burnt area. Old growth bordering recently burnt which in turn bordered recovering vegetation. As a result no fire event could exterminate all vegetation, as there was always large patches of vegetation too young to be re-burnt (<5yrs). The Aboriginal people of Australia operated in much the same way with their 'fire stick' tradition, introducing fire to areas they travelled through and using it to flush out animals for food. Each time a fire was set it would run with the wind until the humidity increased or the wind changed or a 'south-west weather change' brought rain. Consequently long strips of burnt vegetation protected chunks of old growth in an almost natural arrangement. Early europeans disrupted the balance only because their tried-and-true practices of Europe where not matched to the complexity of Australian bush. total exclusion of fire was not a good option in the long term. The accumulation of dead wood (aka fuel load) increased with time and the resulting fires burned too long and too hot thus exterminating even the most resilient plants. When I lived in South-west Australia we could have as many as 8 bush fires at once all started by lightning and in all forms of topography from high stone hills to low sand dunes. Recently management practices have changed dramatically and now West Australia has some of the best fire management operations in Australia. But did this change come too late for our little friend the Western Ground Parrot?

Tune in next week when we hear more about the Western Ground Parrot. Until then ponder this page as it is intended, i.e. only the views of the author and intended only to tell a story with as much accuracy as he can muster.

Posted by Brent Barrett on 09/15 at 04:15 PM

Further mysteries of science - Kakapo

by Brent Barrett

Last week we explored some aspects of endangered species behavior that often leave researchers at loose ends. These referred to parrots which migrate or those that are nomadic (with large home-ranges). The difference between these examples are a matter of known and unknown location and how that translates to control of conservation effort. A migratory bird has a distinct period of absence from your conservation land. During this period of absence we know that the bird is not to be found, having already departed to the summer/winter grounds. We can then plan conservation around the periods that the bird returns for feeding or breeding. Protection of the necessary habitat can be performed and negotiations can be entered with the people in the area where your parrot migrates too. In a wide ranging nomadic population like the Night parrot, when no birds can be reliably located, conservation managers have very little option for protecting this species. Today I want to talk about the New Zealand Kakapo (Strigops habroptilus) a very closely managed population of which every individual is known and carrying a radio-transmitter (tracking device). However despite this very precise monitory situation many unknowns hamper conservation efforts.

The Kakapo is the heaviest parrot in the world ( 2-4 kg) and one of the few non-cavity, ground nesting parrots. Although this is unique enough this long lived parrot is also entirely nocturnal, flightless and employs a Lek breeding system. We know a lot about the wonderful Kakapo, the males carve bowls out of the soft soil below boulders or at the base of dense shrubs, carefully positioned above a slope for greatest acoustic range. At night they inflate an air-sac and emit a number of deep-base notes. A number of males will occupy an 'booming-arena' where the female selects a suitable mate. The female will return every few days to mate prior to the laying of her subsequent eggs (which typically number 2-5 and hatch asynchronously). The male does not take part in the raising of the young, instead the female incubates all day then forages by night in order to feed herself and the growing chicks. Due to time and food constraints each nest typically fledges only two young. These chicks can be either bright green or olive colored and it is possible for both colors to occur in the same brood.

We know these factors of breeding biology from direct observation and close monitoring over nearly 20 years. The breeding season during which I worked produced 24 fledged bird from a source population of only 62 individuals. That represented over 30% increase in population during one breeding year. The problem is that these breeding years are few and far between (typical of an animal with a slow metabolism like Kakapo). The real problem is that researchers don't know exactly what triggers this breeding and have no idea how to increase its frequency. Consequently we rely on maximizing the output of the few breeding events that occur. This year could be one of those monumental breeding seasons, triggered by a large seeding event from the native Rimu tree. We do know that breeding responds favorably to large seed fall and, mysteriously, that the birds predict this seed fall event three months in advance of the fruit falling. Such is the delicacy of the preparations for breeding. So in this example, we know almost all there is to know about the life and times of the Kakapo but are stumped when asked the question what makes them breed and how can be increase the number of breeding events from once every three years. In such a situation managers can only ensure that all young hatched survive and, prior to that, manipulate the pairing so that infertile males are not breeding with females and producing infertile eggs. In 2001 90 eggs where produced of which 40 were infertile (refer to photo of infertile Kakapo eggs in an egg carton).

Posted by Brent Barrett on 09/09 at 12:34 AM

Comments: