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Kea documentary

December 10, 2010 1 comment

For those interested in wild parrots, there’s a full-length documentary on keas at this site:

http://www.nzonscreen.com/title/kea-mountain-parrot-1993

I’ve been to New Zealand and have seen keas and they are fascinating birds. I’ve written more about them here:

Meet the Kea: New Zealand’s Mountain Parrot

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Play Behavior in Wild Parrots

October 7, 2009 3 comments

I wrote an article a little while ago about play behavior in wild parrots.  It focused a lot on the parrots of New Zealand, since the play behavior of three species from there (Kea, Kaka, and Kakapo) has been well studied.

The article has been published in the “Companion Parrot” magazine, which can be downloaded over here:

http://www.members.companionparrot.com/

The issue has a lot of other articles about play in parrots as well. Plus, by signing up, you can get access to various forums and can read a lot of other parrot-related articles.

I’ve also posted the whole article below as well.

Enjoy!

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Play Behaviour in Wild Parrots


Play is very common in young mammals, but it appears to be much less widespread in birds.  This could be for one of two reasons: either young birds simply do not play as often as young mammals, or play in birds is simply an understudied area.  Even if it isn’t common, play is definitely not unheard of in birds.  For example, young birds of many species, including song sparrows, will spar playfully with each other, and some raptors will fly while holding an object, only to release it and chase and catch it as it falls.  And of course, anyone who has interacted with young pet parrots has probably seen birds play.

 

What is Play?


Relatively few scientific studies have been done on play in birds in comparison to ones done on play in mammals (especially primates).  Play is a difficult area to study because clearly defining “play” in a way that differentiates it from other activities is quite challenging, even though most of us probably know it when we see it.  Defining it is tricky since there are no actions that birds only reserve for playing.  Play in both birds and mammals generally involves actions used in other contexts, such as foraging, courting, fighting or mating.  However, in play, the actions do not seem to serve any immediate function, and the actions may be incomplete or exaggerated when compared to their more “serious” counterparts.  The motivational basis also appears to be different.  Play tends to be self-rewarding, since food or mating opportunities are not obtained directly from play.  Animals basically seem to play for fun.

 

Role-reversal and self-handicapping are two common features of play.  Role-reversal occurs when one animal takes on a different social role during the play session.  For example, during play, an adult dog may place itself in a submissive posture towards a younger dog.  Self-handicapping occurs when one animal does not use all its strength during the play bout.  For example, an animal would not bite as hard as it physically could during a play session.  Often, an animal must learn how hard it can bite during play.  Most puppies learn that they lose play opportunities when they bite too hard.  Most young parrots need to be taught this as well.

 

Play must also be differentiated from vacuum activities and behaviors like pacing.  “Vacuum activity” is the name Konrad Lorenz gave to behaviors that appear in animals even though there is no stimulus present that normally induces them.  In other words, they appear in a vacuum.  Behaviors that an animal has a strong “drive” to display can appear in such a vacuum.  For example, chickens normally dust bathe, and may make motions as though they are dust bathing even if there is no dust.  The “false” dust bathing is not really play, although it is similar in that it serves no immediate function.  Pacing in caged animals is considered a vacuum activity by some. A pacing animal may not be moving around in response to any stimulus or for any obvious reason (such as to find food), but it is clearly not playing.

 

Even with all of the cautions one must take when evaluating whether a behavior is play or not, it is clear that play does occur in several wild bird species.  This play falls into three categories: object play, locomotive play, and social play.  Object play occurs when an animal manipulates or tosses an item that has no obvious use to it.  Ravens often engage in object play.  Young ravens will toss around and manipulate nearly any interesting object they find.  Raptor fledglings will also play with objects, such as chunks of moss.

 

Locomotive play involves a single animal.  During this type of play, the animal will hop, swing, summersault, and move in an apparently exuberant fashion, but not necessarily to get anywhere.  Some parrots like to sit on swings and flap their wings to make them move and this is an example of locomotory play.

 

Social play, where birds play interactively with a partner of their own species, is not widely documented in birds, but it has been studied in two species of hornbill, Eurasian babblers, several species of corvid (ravens, crows, magpies, jays, and relatives), and several species of parrot1.  Among birds, it appears most important in the species that have very large brains relative to their body sizes.  The parrots and corvids certainly fall into this category.  Parrots and corvids are the two most playful of bird types in general, and both do play in the wild.

 

Play in Keas


Social play has been very well-studied in three of New Zealand’s parrot species: the kea (Nestor notabilis), the kaka (Nestor meridionalis), and the kakapo (Strigops habroptilus).  Of these three, the kea displays the most variety in types of play observed. The species is quite infamous for its playful nature, curiosity, and propensity to cause troubles for humans.

 

Keas are rather peculiar animals and in many ways are quite unlike most other parrots.  Firstly, most of their plumage is earth-toned, rather than being the more typical brilliant greens, reds, and blues of many other parrots.  They are mainly olive green, but do have some scarlet feathers on the underside of the wings and their flight feathers are a striking turquoise-blue.  The outer side of the tail is a dark shade of sea-green and has a dark band near the end of it.  The underside of the tail, like the underside of the flight feathers, is brown with yellow stripes.  The beak also contributes to the birds’ unique appearance: the upper mandible is long, thin and spear-like.  They need such a long beak to dig for tubers and roots to eat in the winter.  Unlike most other parrots, keas live in alpine regions which are covered in snow during winter.  They are also truly omnivorous and will eat other animals.

 

It’s the kea’s behavior, however, that has really made it quite famous.  The complexity of their social behavior rivals that of many primates, and they are insatiably curious, as anyone who has seen them in the wild can attest to.  Young keas will investigate any new and interesting thing they see in their environment, from a tasty-looking seed, to a hiker’s backpack, to a skier’s new SUV.  Keas can be rather attracted to human settlements, presumably because they provide plenty of interesting things to poke through and potential sources of new food.

 

Their curiosity gets keas into trouble with humans quite frequently.  Leave a backpack outside unattended in kea country and there’s a good chance that a kea will come along, chew it up, and scatter the contents everywhere.  Even vehicles are not safe from kea beaks.  Keas love to rip the antennae and wind shield wipers off of cars.  In one case2 a group of keas tore the rubber around the windows off of a vehicle, which caused the window to cave in.  This gave the keas access to the vehicle’s interior.  They tore up everything they could and ultimately rendered the vehicle undriveable.

 

Needless to say, I was relieved that I had gotten extra insurance on my rental car when I saw a juvenile kea loitering around the parking lot of the motel I was staying at on a recent trip to New Zealand.  This was at Milford Sound, right at the south end of the South Island.  I had found a family of three keas there, which I presumed were a male, female, and their offspring.  The juveniles are quite easy to differentiate from the adults, as they have some orange shading around the eyes and on the beak that the adults lack.  The adults were busy digging in the dirt for roots to eat, but the juvenile spent much more time exploring the area around a restaurant.  He hung around on the roof and manipulated a piece of plastic sheet he dragged out of a pipe.  He squealed at his parents in a hunching posture as they foraged.  They didn’t mind him at all, until he flashed the red patch under his wings at them.  This, apparently, is a threat behavior, and he was charged at by one of his parents for that gesture.  The hunching behavior I saw is one displayed primarily by juveniles, and adult keas will generally act much more gently towards a hunching juvenile.

 

The play repertoire of keas has been very well-studied2, 3.  Along with ravens, keas probably have the most diverse play repertoire of all birds.  However, unlike in most other birds, play persists in wild keas past the fledgling stage.  About 25% of all participants in play sessions among wild keas are subadults or adult females3.

 

Social play is very common in wild keas.  Often, one kea will initiate a play session with another by cocking its head to one side.  This gesture would indicate to the other kea that the next actions it takes are in play and are not to be taken as aggression.  The “head cock” seems to be similar to the play bow in dogs, where one dog will initiate a play session with another by bowing with its front feet and head lowered.

 

Two juvenile keas playing can be very rough with each other, and act much like puppies play wrestling with each other.  One kea may jump on another and “pin” its partner upside down on the ground.  A pair of playing keas may also shove each other around with their feet.  Some keas will “dive bomb” another kea in an attempt to knock it over.  Playing keas will also lock their bills together.  Bites are common in kea play sessions, and keas will even drag each other around on the ground.  Sometimes, a kea being bitten in play will squeal or jerk away, but serious injuries are not a component of play in keas.

 

Young keas also love to play with objects, either alone or with another kea.  Tug of war is a common kea game.  A lone kea may also pick up non-edible objects like rocks or trash and hold or manipulate them.  A kea may also toss an object in the air, and may exuberantly hop or flap as it releases the object.  A kea may also toss an object at a play partner and adult keas courting each other may also toss objects to each other.

 

Finally, keas often hop towards other birds during play.  Hopping and jumping are major components of their play repertoire in general.  Two keas will often jump and flap next to each other during play.  Pet individuals of many other species hop during play as well, especially lories, caiques, and small cockatoos (particularly the bare-eyed variety).

 

Play in Kakas


The kea’s closest evolutionary relative, the kaka, can also be very playful birds, and their play behaviour has also been examined in detail by biologists3.  Kakas occur in forests on both the North and South Islands of New Zealand.  They too are large parrots – about 45 cm tall – and look similar to keas but are mainly dark brown.  Their beaks are also broader and heavier.  A kaka’s chest is dark red, as are the undersides of its wings.  I saw several of these handsome birds in the forest surrounding the Mount Bruce Wildlife Centre on the North Island, about a two hour drive north of Wellington.  They are very social, noisy, and acrobatic birds.  Several birds I saw were quite capable of playing or foraging while hanging upside down in a tree by one foot.

 

Kakas spend more time up in trees than keas, and do much less of their foraging on the ground.  Juvenile kakas do play-wrestle as keas do and will jump on each other, or engage in mutual foot pushing.  However, play among juvenile kakas is a bit less rough than play among keas.  For instance, kakas do not bite each other during play sessions as often and they never bite their partners hard enough to make them jerk away or squeal.  This could be because kakas have bigger, stronger beaks than keas.  If a kaka were to put any pressure into a bite it gives a play partner, it could inadvertently cause a painful injury.

 

Being primarily arboreal, young kakas do spend a lot of time playing in trees.  Some of this is solitary locomotor play, as young kakas will flap their wings and swing while hanging upside down by one or both feet from a tree branch.  Sometimes, two kakas will hang in a tree next to each other and attempt to push each other out of the tree.  The two birds may even fall out of the tree together.  Overall, kakas spend much more time playing in trees than keas do.  When keas play in trees, they usually spar with their beaks or push each other with their feet.

 

Kakas also differ from keas in that they do not incorporate objects in play as often as keas do.  Young kakas will hang upside down in trees and rip branches or fern fronds off of the tree, or shred other types of vegetation, but that is the extent of their object play.  Keas, on the other hand, will play with nearly anything they find in their environment.

 

Play in Kakapos


The kakapo is a very unusual, unparrot-like parrot.  They are quite heavy (4.5 to 9 pounds) and are flightless.  A high proportion of New Zealand’s native birds are flightless because there are no native mammals there, aside from two bat species.  Since they do not need flight to escape from mammalian predators, many of New Zealand’s species have evolved to become flightless.  Unfortunately, when humans introduced cats, stoats and other predators to the country, populations of many flightless birds, including the kakapo, suffered greatly.  Many of them have no natural fear of mammals and so they were easy prey for predators.  Today, there are only 86 kakapos left, and all have been moved to small, predator-free offshore islands.

 

Play has been studied in captive kakapos who were being raised at a specialized facility at Nelson, on the South Island4.  These kakapos were later released into the wild, so contact with humans was kept to a minimum while they were being hand reared.  The behaviors seen in them should be similar to behavior displayed by wild kakapos.

 

Juvenile kakapos are quite gentle during play.  They will use their beaks to nuzzle another bird or grasp its feet, beak, or feathers.  However, they do not bite each other during play.  Overall, play fighting in kakapos is rather mild.  They also do not display the head-cocking behavior seen in keas or kakas.

 

Young kakapos will hop towards other birds and sometimes will push another bird with their feet.  Kakas hop towards other birds with their heads cocked to the side to initiate play sessions, but kakapos do not seem to hop as a way of initiating play.  However, excited kakapos will hop and flap their wings.  Both keas and kakas will roll onto their backs while waving their feet in the air during social play interactions.  Young kakapo will roll onto their backs like that as well, but it is often during solitary play.  Young kakapos will also sometimes place their chin over the neck or back of another kakapo.  Keas and kakas do not display this “chin over” behavior.

 

Unlike keas, kakapos do not incorporate objects into play, although some young kakapos will chew branches and will manipulate other objects they find.  Kakapos also do not hang in trees as kakas do, because kakapos spend most of their time on the ground.  Some will climb trees to find food, but they are primarily ground dwellers.

 

Why the Differences?


Keas, kakapos, and kakas are all closely related, but display different play behaviors.  For example, keas will play with objects, while kakas generally do not.  What could account for that difference?  In general, object play is found most often in generalist species like keas that do a lot of exploring.  Species that can live in a variety of habitats, or can eat a wide variety of foods, are considered generalists.  Crows and their relatives also fit this description, and like keas, are among the most behaviorally flexible of all birds.  Adult kakas, despite being large-brained, intelligent birds, are more afraid of new objects and situations than keas tend to be.  Kaka diets also include a smaller range of items than the typical kea diet.  For example, kakas do not eat other birds or mammals like keas do.  Perhaps its harsher environment means that the kea must accept a larger variety of food sources than the kaka.  In turn, keas have evolved to be bolder and more exploratory to locate a greater variety of foods.  Keas also stick around their parents for a longer time than kakas do, perhaps because it takes them longer to learn to find and eat the huge variety of foods they need.

 

Kakapos display fewer play behaviors than either keas or kakas.  This makes sense in light of one of the hypotheses that attempts to explain why play is so common in social mammals.  Social mammals likely learn a lot about the “ground rules” of social interactions by playing with their peers. They learn, for example, about how hard of a bite is acceptable.  This is likely true for social parrots as well.  Kakapos are largely solitary (with the exception of a female with young) and that may explain why their play repertoires are smaller compared to those of keas or kakas.

 

Of course, anyone who has had a kitten knows that non-social mammals play as well.  Kakapos do not play in as many ways as kakas or keas do, but they still do play.  Young animals probably develop better muscle coordination through play, and they get to practice hunting or foraging skills.

 

Another hypothesis attempting to explain why play has evolved in mammals is that it prepares animals to deal with novel situations.  Animals have to be flexible during play and often place themselves in situations they normally wouldn’t be in.  For example, a bigger, older animal may “self-handicap” when playing with a younger, weaker animal, and most animals alter their behavior during play fights to avoid harming their partner.  By practicing putting themselves in different social situations and playing roles they normally wouldn’t, play helps animals learn how to deal with a wide variety of new situations they normally wouldn’t find themselves in.

 

Conclusion


Avian play is a relatively new area of study for biologists, and as it stands, very little is known about how often birds play in the wild.  However, it is clear that many corvids and parrots do play, and a lot is known about play in ravens and the parrots of New Zealand.  The kea is a very playful creature, as is its relative, the kaka.  The solitary kakapo lacks the intensity and variety of play seen in these two species, but it too does show some play behavior.  Play in these species is usually limited to young animals, except for adult female keas. However, many adult pet parrots seem to enjoy play, presumably because they enjoy it and do not have to worry about finding food and caring for their young.  They can afford to spend time on other activities.  The immediate reason why parrots play is, presumably, because they enjoy it. However, it probably evolved and persists in wild populations because it helps juvenile parrots learn about their environment.

 

References

1. Diamond, J., and Bond, A. B.  2003.  A comparative analysis of social play in birds.  Behaviour 140: 1091-1115.

2. Diamond, J., and Bond, A. B.  1999.  Kea, Bird of Paradox: The Evolution and Behavior of a New Zealand Parrot. University of California Press, Berkeley, California.

3. Diamond, J., and Bond, A. B.  2004.   Social play in kaka (Nestor meridionalis) with comparisons to kea (Nestor notabilis).  Behaviour 141: 777-778.

4. Diamond, J., Eason, D., Reid, C., and Bond, A. 2006. Social play in kakapo (Strigops habroptilus) with comparisons to kea (Nestor notabilis) and kaka (Nestor meridionalis).  Behaviour 143: 1397-1423.

Meet the Kaka: The Kea’s Lesser-known Cousin

November 4, 2008 2 comments

This is an article I wrote which appeared in the November 2007 issue of Parrots magazine.

Meet the Kaka: The Kea’s Lesser-known Cousin


Last post, I wrote about my experiences watching keas (Nestor notabilis) on a recent trip I took to New Zealand. Keas are well-known among parrot fanciers for their remarkable intelligence, intense curiosity, and extremely destructive behavior. I was absolutely thrilled to have been able to see some in the wild. I was also able to see groups of another similar parrot that lives in New Zealand: The kākā (Nestor meridionalis). The kaka is not as well-known as the kea and they are extremely rare in aviculture or zoos outside of New Zealand. So, allow me to introduce you to this handsome, little-known parrot.


A North Island Kaka

A North Island Kaka

Introducing the Kaka


Kakas occur in forests in New Zealand. Their name comes from the Maori and Polynesian word for parrot. “Kaka” is also part of the Maori names for other New Zealand parrots: the kakarikis (little parrots) and the kakapo (ground parrot). The kea and the kaka are close evolutionary relatives, and they are only distantly related to other parrot species. Their closest relative is the kakapo, a heavy, flightless, green parrot.

Prior to the 1800s, there were actually three species in the genus Nestor, with the third one being the Norfolk Island Kaka (Nestor productus). This bird occurred on the Norfolk and Phillip Islands, which are about 1000 km northwest of Auckland, New Zealand. The last one died in captivity in London in 1851, although the species was likely wiped out in the wild before then. Norfolk Island Kakas were not afraid of people and were hunted widely for food by European settlers. Others were trapped as pets. Another Nestor species related to the kaka occurred on the Chatham Islands, about 800 km east of Christchurch, New Zealand, but this parrot is only known from fossils and the date is went extinct is unknown.

Norfolk Island Kakas looked very similar to the New Zealand Kakas. The kakas on New Zealand are mainly brown with red-tipped feathers on the belly and the back of the neck, scarlet feathers under the wing and white feathers on the top of the head. They resemble keas somewhat, but are a bit smaller, are brown instead of olive, and their upper mandibles are heavier and broader. The Norfolk Island Kaka differed from mainland kaka in that they were slightly smaller, their cheeks were orange, their chests were yellow and the tops of their heads were brown. They were undoubtedly very beautiful birds. All that is left of the species are a few skins housed in natural history museums. Additionally, the National Museum of Natural History in Amsterdam has two whole specimens, and there are 3D images of them on their website (http://ip30.eti.uva.nl/naturalis/detail?lang=uk&id=51) that can be rotated using a mouse.

Unlike the kea, which occurs only on the South Island, the kaka occurs on both main islands and Stewart Island, along with a few other small off-shore islands. There are two kaka subspecies: The South Island Kaka (N. m. meridionalis) and the North Island Kaka (N. m. septentrionalis). The South Island variety is a bit larger than its North Island counterpart. Both tend to exist at larger densities on off-shore islands where they occur than on the mainland, where populations have decreased since European settlement due to the introduction of non-native predators, such as cats and stoats. Many of New Zealand’s native birds are not afraid of mammals and have no defense strategies to deal with them because they evolved in isolation from mammalian predators. In many areas of New Zealand, introduced predators have decimated native bird populations.


Meeting Wild Kakas: North Island


The first wild kakas I met were living at a wildlife sanctuary on the North Island. I went to Wellington after a conference I attended, with the intention of visiting Kapiti Island. This island, only eight kilometers from the mainland, serves as a sanctuary for several very rare bird species, because introduced predators have been eliminated from it. Parrot species found there include Red-fronted and Yellow-fronted Kakariki and North Island Kaka. Other very rare birds found there include the Takahe, a large, flightless, blue and green rail, and the Kokako, a member of the New Zealand wattle bird family. Less than 200 Takahe, and about 400-500 pairs of Kokako remain. Because it’s easier to keep alien predators off of islands than off of mainland sites, many populations of very rare species live primarily on smaller islands, rather than on either of the two main islands. However, some mainland sites manage to maintain populations of rare native birds by implementing predator-control programs. For example, the Kaori Wildlife Sanctuary in Wellington has a large, predator-proof fence around it to protect native birds including kaka and kakariki.

A North Island Kokako.

A North Island Kokako

Unfortunately, the boats to Kapiti Island did not sail during the few days I was in the area. That was disappointing, but the trip was by no means a total bust and still turned out quite well. I managed to see a flock of free-living kakas and several other very rare bird species by heading north to the Pukaha Mount Bruce Wildlife Centre. This wildlife centre is completely devoted to the conservation of native New Zealand wildlife, and has an information centre including audio-visual displays, several large aviaries containing native birds, a Tuatara display, walkways through restored native forests, a kiwi house, a shop and a café. The center has bred rare kokakos for release into the wild on offshore islands and in the forest around the centre. North Island Brown Kiwis have also been released into the forest, where predator-control programs increase their chances of surviving and breeding. Other very rare birds bred there include the Campbell Island Teal (of which only 20 survive in the wild), and the Shore Plover (of which only 200 birds exist).

The centre also runs a kaka recovery program. After having been absent from the area for 50 years, kaka are now back in the forest around the centre and free-living flocks can be seen from the walkways through there. Wild kaka transported from Kapiti Island and captive-bred kakas were released into the forest in 1996. Other captive-bred kakas were released in following years. This kaka conservation project has been successful so far, because the birds have successfully raised several chicks in the wild and the population is increasing. To give the kakas a better chance at raising young, biologists put some predator-proof nesting boxes out for the kaka.

kaka_preen1

The wild kakas weren’t too difficult to find,because, like most parrots, they have a loud call. Since they call while they fly, I could easily spot birds flying solo or in pairs over the trees. However, several of the birds I spotted were resting in the trees, or preening, since it was mid-day – siesta time for parrots. The kakas blend in well with their surroundings so seeing the quiet, inactive ones took some effort. Other kakas were chewing the bark and twigs off of the trees. Many of the trees in the forest showed evidence of kaka-induced damage. However, unlike keas, which are often found near human settlements, kakas limit most of their destruction to trees. While some individuals will visit backyard bird feeders, most kakas stay in forests away from towns and cities.

Since many of the free-living kaka around the wildlife centre were captive bred, they are offered supplementary food at a feeding station each day at three in the afternoon. When I approached the feeding station before feeding time, several kakas started to follow me, hoping I had their food. They weren’t afraid of me, but they didn’t approach me too close, either. They were very interesting to watch and photograph and would go about their normal activities while I followed them with a camera or spied on them with binoculars, like a parrot paparazzo. The kakas were quite chatty, but they weren’t quite as loud at the keas I saw.

kaka_feeder

At three, workers at the centre added some corn and nuts to the parrot feeder. The parrots all rushed in to grab the best bits. Most preferred to grab a bit of food and dart off to a tree to eat it in peace. Those who stuck around the feeder tried to steal food from each other constantly. Often, one bird would approach another to take a nut or piece of corn, and the bird with the food would wind up dropping it to the ground. They were rather messy eaters and got crumbs and bits of corn all over the ground. Larger pieces of food that wound up on the ground were eventually cleaned up by the kakas, and songbirds and blackbirds would take the smaller pieces. Kakas usually stay off the ground, but not if there’s a good piece of food down there.

Before they are released, captive-bred kakas are given access to a similar feeder so they are used to eating from it. Staff can also monitor the birds from the feeders, and the feeder gives the public a great opportunity to view a free-living flock of wild parrots. From watching the kaka throughout the day, it seems that most do forage just fine on wild food as well. It was very nice to see, first hand, such great results from a parrot conservation project.


kaka_corn2

Wild Kaka Dietary Habits


Wild kakas eat a variety of food. Somewhat like lories, their tongues are bristled, which helps them lick up nectar. In the process of feeding on nectar, they help pollinate a lot of flowers. Some kaka will visit special bird feeders stocked with a sweet liquid, like big hummingbird feeders with a place for the birds to perch. Kakas also eat berries, seeds, tree sap, honeydew and some invertebrates. They will often dig grubs from rotting logs, and they can easily peel bark off of trees with their strong beaks to get the sap. They do not feed on the ground as often as keas do, and in fact, look a bit awkward skipping along on the ground. Kakas are forest birds and spend most of their time in trees. They are very acrobatic, and many can eat while hanging upside down by one foot.


Play Behavior in the Kaka vs. the Kea


Overall, kakas are somewhat less exploratory and playful than their mountain cousins, the keas. However, as is the case with most parrot species, young kakas will spend some time playing. Diamond and Bond (2004) studied the play behavior of both kakas and keas, and compared the play-styles of the two species. This represents one of a very small number of formal studies done on parrot play.

Play in the kaka is limited to young birds, while it is found in both adult and young keas. Keas will also play in groups of three or more birds, while kakas generally will not. Both species engage in rough play-fighting, but keas are much more aggressive about it than kakas. For example, kakas will use their powerful beaks to nip at each other in play, but they don’t seem to put enough pressure into their bites to make their opponent feel much. However, when a kea bites a playmate, the bird being bit will sometimes pull away like he’s been hurt, although playing keas rarely make each other bleed. Perhaps this difference is due to the fact that kakas have bigger, heavier beaks than keas. If the kakas put any pressure on another bird with their beaks, they would likely cause a serious injury.

Playful keas or kakas will jump on or push their opponents with their feet. Both species sometimes initiate play sessions by cocking their heads to the side, although this move is far more exaggerated in kakas. This behaviour seems to be the equivalent of the “play bow” in dogs, where the dog places his front feet on the ground while his rear stays up in the air. These behaviors let the animals around know that the following behavior is in play and is not to be taken as aggression. Like caiques or lories, keas and kakas also approach potential play partners by hopping.

Keas will play with objects, while kakas generally do not. What could account for that difference? In general, object play is found most often in generalist species like keas that do a lot of exploring. Crows and their relatives also fit this description, and like keas, are among the most behaviorally flexible of all birds. Adult kakas, despite being large-brained, intelligent birds, are more afraid of new objects and situations than keas tend to be. Kaka diets also include a smaller range of items than the typical kea diet. For example, kakas do not eat other birds or mammals like keas do. Perhaps its harsher environment means that the kea must accept a larger variety of food sources than the kaka. In turn, keas must be bolder and more exploratory to locate a greater variety of foods. Keas also stick around their parents for a longer time than kakas do, perhaps because it takes them longer to learn to find and eat the huge variety of foods they need.


South Island Kakas


After spending a few days on the North Island, I headed back to the South Island and eventually made my way to Stewart Island, which is a one hour ferry ride from the South Coast. Some introduced predators do exist on the island, although stoats – extremely efficient bird predators – are absent. As a result, the island is rich in birdlife and is a wonderful place for a bird watcher to spend a few days on. South Island Kaka, Red-fronted Kakariki and Yellow-fronted Kakariki are the parrot species present on the island. In my few days there, I saw several Red-fronted Kakariki and kaka right in Oban, the only town on the island. The kakas were not too difficult to spot at all, due to their habit of calling while in flight. They generally started calling very early in the morning, before the sun was fully up. I needed no alarm clock out there.

I saw plenty of interesting birds on Stewart Island, but the best place near Oban to see birds was undoubtedly Ulva Island. This small island, a five-minute boat ride from Oban, has been cleared of predators, and many rare birds have been reintroduced there. Kakas are present, and while I only saw a few of them far up in the trees while I was there, I saw plenty of evidence of their activity in the form of tree damage. Many trees had places where bark had been stripped off by kaka.

Unfortunately, I saw no kiwis, which are present on the island. Stewart Island is one of the few places were one has a decent chance of spotting a kiwi in the wild, since the kiwis there will forage in the daytime, shortly after the sun rises and before the sun sets. Most other kiwis are completely nocturnal. At any rate, I managed to see many kakariki, which were, of course, on my “must see” list. More on them and the other birds on Ulva Island next issue!


Literature Cited


Diamond, J., and Bond, A. B. 2004. Social play in kaka (Nestor meridionalis) with comparisons to kea (Nestor notabilis). Behaviour 141: 777-778.


Kaka Facts


Habitat: Native New Zealand forest on the North Island, the South Island, and Stewart Island. They are also common on many small offshore islands, such as Kapiti Island, Little Barrier Island, Tiritiri Matangi Island, and Ulva Island.

Conservation Status: Populations have declined on the mainland since European settlement.  Deforestation and the introduction of non-native predators are primarily responsible for the species declined. Introduced possums and wasps also compete with kaka for food.  Overall, the species is considered vulnerable.

Breeding Habits: Kakas breed from September to March. As is the case with most parrots, they use holes in tree trucks as nests.  Kakas will often enlarge the holes.  The female incubates the eggs for three weeks and she only leaves the nest twice daily to be fed by the male.  Chicks fledge 9-10 weeks after hatching, and they are fed for another week afterwards.

Other Habits: Outside the breeding season, they live in small, loose flocks of up to ten birds.  Some kakas on islands such as Kapiti are very bold and will approach people readily.


Additional Photos


kaka_tree2

kaka_eat



Meet the Kea: New Zealand’s Mountain Parrot

November 2, 2008 2 comments

This is an article I wrote for Parrots Magazine issue 126. I also wrote an article on the Kaka and the Kakariki, which I’ll be posting later this week. This version is a bit longer than the one that appeared in the magazine.


Meet the Kea: New Zealand’s Mountain Parrot



Last year, I learned that one of the scientific societies I belong to was going to hold its annual conference in Christchurch, New Zealand, during June, 2007.  I was elated to hear this – after all, who wouldn’t want to visit such a beautiful country?  In particular, I enjoy bird watching and hiking, and New Zealand has many national parks and several unusual bird species.  Now I had a good reason to go there.

The charming, needle-nosed kiwi is generally the animal that most people think of when the subject of New Zealand wildlife is brought up.  However, to me, another animal came to mind when I realized I had the chance to visit New Zealand.  It’s an offbeat creature that is among the most intelligent and adaptable of all non-human animals.  I decided that I must see this animal in the wild on my trip.

The animal I refer to is a very clever, curious parrot.  And it’s no ordinary parrot. To most people, parrots are brightly-coloured inhabitants of steamy tropical rainforests.  However, this parrot makes its home at chilly, high-elevation sites that are often covered in snow.  It is also cloaked in plain, earth-toned feathers rather than the bright green or blue ones many parrots have.  I am referring, of course, to the kea.  New Zealanders I met often described keas as being “cheeky,” and there’s even a café on the West Coast called the “Cheeky Kea.”  Other verbs often used to describe it are “mischievous”, “roguish”, and “clownish” — all apt descriptions of this peculiar creature, as shall become apparent.

I asked a few people I know who have visited New Zealand where I could see keas.  Anyone I asked who had visited the mountainous national parks on the South Island had seen keas, and a few people assured me I would see them if I went to any of these tourist-frequented areas.  Two different people also noted that, “You won’t have to find the keas – they’ll find you!”

Scenery in Westland Tai Poutini National Park

Scenry in Westland Tai Poutini National Park.

So, after the conference, I took the TranzAlpine train across the Alps and rented a car in Greymouth.  I explored the beautiful and diverse Westland Tai Poutini National Park, but despite doing a fair bit of hiking, I found no keas.  So, I made my way south, and drove to Milford Sound, in Fiordland National Park.  The scenery along the road to Milford Sound is absolutely fabulous and includes rocky mountains, thick, emerald-green forests and several mirror-like lakes.  The road is often clogged with tour buses, but it wasn’t so bad in the winter and I lucked out and got a perfect, clear day for my drive.

I made it to Milford Sound shortly after most tour buses had left so I had the place almost to myself.  I was immediately treated to the site of a lovely White Heron, or Kōtuku, a bird that is very rare in New Zealand.  I also found some busy Silvereyes, a pair of black Oystercatchers, and some Paradise Ducks.  There were “Please Do Not Feed the Kea” signs around, so I figured there must be some keas in the vicinity.  For the moment, I decided to try to photograph the heron and the ducks.

The place was fairly quiet except for the ethereal song of the Bellbird.  I crept towards the heron and snapped some photos.  I then sat on a bench for a bit, to enjoy the view and the Bellbird’s songs, until a loud, shrill screech broke the silence. I had heard that sound before at an aviary at the zoo in Christchurch.  Keas!

The kea’s call is very distinctive sounding and really can’t easily be mistaken for any other bird noise.  The Maori actually named the bird after its call: Keeeaaaaaah!  I followed the noise and came across the site of a young kea sitting on a very short, stone fence.  He was hunched over with his wings out alongside his body, with the tips touching the ground.  With body feathers loose and fluffed out, beak down and open, and tail fanned out, he was squealing at another kea on the ground, who was digging around for roots.  I watched the juvenile kea pester his elder for a while, when I spotted a third one up on a roof, who was calmly surveying her surroundings.

What was the juvenile trying to convey with his odd posture?  At first, I figured that he must be begging the other kea for food.  But the posture wasn’t quite right, as begging parrots tend to look up at, not down to, the bird they are begging from.  With his head and wings down, the young kea could have been taking on a submissive posture, but the adult seemed to be backing away from the fluffed-up, noisy juvenile.

I found out later he wasn’t necessarily begging to the older kea, nor was he solely trying to be submissive.  He was taking on a posture that Judy Diamond and Alan Bond call “hunching” in their book, Kea: Bird of Paradox – the Evolution and Behavior of a New Zealand Parrot.  Of all age and sex classes, juvenile keas hunch most often and juvenile males do it more than females.  Juveniles most often hunch to adult males and they generally vocalize while they are hunching.

Now, keas – like most wild parrots – can be very possessive of food. However, adults will allow hunching juveniles to feed very close to them.  Additionally, adults will sometimes try to drive other keas away from a patch of food.  But if a juvenile kea hunches towards an adult, the adult will be much less likely to try to drive the juvenile away. Juveniles will also hunch to any adult, while they only beg from their male parent once fledged.  Later on in the evening, I saw a juvenile kea hunch to two adult keas in a short time period.

A hunching kea is being both mildly aggressive and deferential at the same time. He pushes the adult away, but indicates with his lowered beak and wings that he intends no real harm.  Generally, the adult was gentle towards the juvenile, except for one small incident.

At one point, when the adult wouldn’t move away from the juvenile, the juvenile stood up taller, fluffed out his head feathers and spread his wings out.  Now, if a kea wants to intimidate another kea, he’ll show the red under his wings, much like a matador provoking a bull with a red cape.  The adult wasn’t pleased with this insubordination, and the two got into a brief tussle, rolling around and nipping at each other.  The spat ended rather quickly, and the two went back to foraging and exploring like nothing had happened.  It’s rare for parrots to seriously injure each other over anything other than nest holes and adults will almost never harm juveniles.

How could I tell the juvenile from the adults?  It’s actually quite easy with keas.  Young keas have an orange eye ring and an orange lower mandible, while these are black in adults (over 3 years old).  The males and females are a bit more difficult to tell apart.  Males are usually about 20% heavier than females and their beaks are longer.  However, it can take a lot of kea watching to be able to tell the difference, so while I refer to certain birds in this article as “he” or “she,” I cannot say that I’m completely certain of what sex the birds I was watching were.

After sitting and watching the keas for a while, I could see why all the “Do Not Feed the Kea” signs are necessary.  This trio of keas was not scared of humans and it could be tempting to toss them treats, particularly when they look at you and wail.  However, it’s never a good idea to hand feed wildlife, because it could make them dependent on human food.  Additionally, the snacks humans eat are often unhealthy for animals, and being handfed can make wild animals very pushy and aggressive towards people.  However, these keas, while they let me get quite close, did not come to approach me.  They went about their business as though I wasn’t there.  Hopefully, that means people are obeying the signs.

That was a bit different from my experience with the Sulfur-crested Cockatoos I saw in Sydney during a stopover there on the way to Christchurch.  They were gorgeous birds and I loved watching them, but one did come to chew on my coat and shoes while I sat photographing them.  Later, I saw a few young people feeding them, so the bold behavior of the cockatoo was likely due to his expecting food from me.  He even poked around in my pockets (“Where are the snacks?”) before I stood up and walked off.  Luckily, these cockatoos still spent a lot of their time foraging on natural foods and most ignored all the people around.

Back to the keas: The three I saw displayed the characteristic inquisitive and destructive nature their species is famous (even infamous) for.  They spent a lot of time foraging for roots, but they also stopped to poke around on the ground near the rubbish bins behind a restaurant and the juvenile started ripping up some plastic he found on a roof.  Another adult jabbed at a tire for a bit.  The rubbish bins were shut tight and sealed so the keas couldn’t go in them to eat scraps and toss trash everywhere.  When keas forage in trash bags or piles of vegetation, they will literally toss non-food items out of the way after inspecting them.  They can be quite clever at getting access to trash and may simply shove aside heavy objects placed on the bins by people to keep the keas out.

No one will ever call the kea a fussy eater, since they will gladly eat almost anything that’s edible.  This includes the parts of over 100 plant species (especially the fruits and seeds), snails, insects, meat and garbage.  Some will drag shearwater chicks from their nests to consume them, and they will eat rabbits and rodents.  They will also scavenge on sheep carcasses, and some will even kill sheep by digging at their backs with their beaks.  The government declared a bounty on keas because of this in the 1880s, which lead to a sharp decline in the species’ abundance.  Keas are now a protected species because there are less than 5000 of them left.  Instead of shooting keas, ranchers can report problem birds to the department of conservation, who will send officers to investigate the problem and relocate problem birds.

I’ll admit I was skeptical when I read about the kea’s predatory behavior towards large mammals.  Really, parrots killing full-grown sheep?  But it’s true, and keas have been caught on video tape attacking sheep.  They will land on sheep’s backs and start pulling off wool, sometimes going farther by digging holes in the sheep’s skin.  The sheep can then die of infection. Keas will eat sheep carcasses, going for the kidneys first.

Before humans arrived, land mammals besides bats had been absent on New Zealand for millions of years, and keas – as bright and curious as they are – quickly figured out that sheep can be a very valuable food source.  This is almost certainly due to their tendency to examine new items.  In contrast to keas, most adult wild animals are wary of things they’ve never seen before, and that’s why they avoid people.  When sheep arrived in New Zealand, keas likely went to check them out by landing on them and picking at them with their beaks.  The wool was no doubt fun for them to pull out, and the sheep were probably like big, furry toys to them.  At some point, various birds figured out they could reach the edible flesh by digging at the sheep hard enough. Keas also examined the bodies of sheep that died naturally, and found out that they were a rich, nutritious food source.  All that fat and protein would be like winning a lottery jackpot for a kea, especially in winter when high-energy food sources are scarce and kea are at a real risk of starvation.

Aside from allowing them to learn to exploit new food sources, their intelligence also makes keas a challenge for biologists to trap.  Diamond and Bond (1999) report in their book that they needed to catch and band keas so they could identify individuals in their studies on them.  They set up a trap baited with butter – a fine delicacy for keas – and placed a drop net over it.  The keas quickly learned to get the butter while avoiding capture.  One bird would run over, jiggle the trap just enough to make the net drop, and then go back and eat the butter through the net.  Other birds would wait until another fellow kea tripped the net, and then they’d run in and try to steal the butter through the net before the biologists came to mark and release the trapped kea.  Others mastered the skill of quickly bolting under the net and grabbing some butter and running with it before the net fell.

Biologists doing studies on captive keas have also shown that these parrots have remarkable problem-solving skills.  For example, in Austria, biologists gave seven captive keas access to a long, wooden perch, in the middle of which hung a long string which had an object smeared with a mix of butter and egg yolk on the end of it.  This experiment was done by Dagmar Werdenich and Ludwig Huber and the results were reported in the journal Animal Behaviour in 2006. The intention was to see if the keas would figure out how to get the butter.  The only way they could do so would be to pull the string up, hold the pulled-up piece of string down on the perch with the foot, and repeat until the butter was in reach.  The butter was not accessible from the ground or from flight.  The keas had never handled string before.  This puzzle is extremely difficult for most animals to figure out, although ravens – another very intelligent animal – can often figure this out quite quickly.

What about the keas?  Well, the butter sure intrigued them, and all showed immediate interest in it.  One fledgling took several trials over the span of a month before he managed to get the butter.  His lack of foot coordination hampered his first efforts at getting it.  The adults, however, all figured out the right sequence of motions to do to get the butter in one trial, in six minutes or less.  One individual took a mere 9 seconds on her first trial and four out of six adult birds got the butter in 16 seconds or less.  The birds who took a few minutes to get the butter improved their performance in subsequent trials, showing that keas can learn from their mistakes.  There’s almost no chance that the sequence of actions the keas used to get the butter was instinctive, and some keas immediately solved the problem, showing that it wasn’t necessarily trial-and-error learning.  They had to use their insight to get their reward.

Back at Milford Sound, I watched the keas until it became dark and then I headed up to the motel.  However, that wasn’t the last of my kea sightings for the day.  I spotted one with my flashlight messing around under a truck while I was getting my luggage out of my car.  Seeing that, I was glad I got extra insurance on my rental car.  Keas will chew the parts off of cars, especially the wipers.  Keas will also pick through any other interesting items humans leave in their reach, including backpacks, coats, laundry on a clothesline, tents, or boots (the latter they’ll go for even is a person is still wearing them).  Keas have also been known to get into mountain huts through chimneys.  Once in, they’ll have a grand time shredding and ruining anything they find and scattering the remains about.  Dishes may be smashed, and even the door and window frames could be attacked and destroyed.  It’s generally the juveniles that cause this kind of trouble. After leaving their parents, young birds flock together until they’re old enough to start their own families.  While adult keas are curious and enjoy chewing things, juvenile keas are extra-inquisitive and destructive.

A juvenile kea plays with some garbage

A juvenile kea plays with some garbage

Later on, an hour after seeing the juvenile under the car, a group of keas, as people had predicted, found me.  I heard a familiar squealing sound outside my motel room door, and outside were three keas (the same from before?) milling around.  One juvenile was hunching to and pushing around two other keas, who were generally exploring the parking lot.  I watched them for a while and went back inside. I could hear them busily running around the boardwalk outside my room for another half hour or so.

While they must spend a lot of time foraging and resting, particularly in winter, keas also spend a lot of time exploring (even if not hungry) and playing.  Their play behavior is the most complex of any bird species.  Keas will throw items straight up in the air in play, sometimes jumping up exuberantly after the thrown item.  Such “object play” is extremely rare in birds, but keas will play, either alone or in a group, with any interesting items they come across.  Juveniles really enjoy playing tug-of-war and keep-away.  Much of their tussle play is similar to the wrestling that puppies will do, and like ferrets, they will also drag each other around by the back of the necks.  Juveniles do most of the playing, but adults are not adverse to a short play session as well.

I saw the keas again the next day, and two of them were digging in the dirt and exploring the territory around restaurants and houses.  The third kea was up a tree loudly sounding off, which enabled me to find the trio quite quickly.  I watched and photographed them for a while, until I finally had to head out to Invercargill, where I could take a ferry to Stewart Island to look for more wild parrots, kaka and kakariki.  More about them in the next postings!

References

Diamond, J., and Bond, A. B.  1999.  Kea, Bird of Paradox: The Evolution and Behavior of a New Zealand Parrot. University of California Press, Berkeley, California.

Werdenich, D., and Huber, L.  2006. A case of quick problem solving in birds: string pulling in keas, Nestor notabilis.  Animal Behaviour 71: 855-863.

Kea Facts – Sidebar

Scientific name: Nestor notabilis

Size: 48 cm tall, 700-1000 grams.

Description: Keas are primarily olive green, and most of their feathers have dark edges.  Under the wings are red feathers and feathers with yellow stripes.  The outer webs of the primary feathers are blue and the tail is bluish-green with dark tips. The legs are grey and the eyes and beak are dark.

Distribution: Mountainous areas of New Zealand’s South Island, particularly in national parks and areas above 600 m in elevation.

Habitat: Areas in and around human habitations, beech forests, subalpine scrub, and alpine grassland.

Diet: Omnivorous; keas will eat plants, insects and meat. They are generally found close to beech (Nothofagus) forests, and when these trees mast seed (every 4-6 years), the keas rely on them heavily for food.

Breeding: Occurs from July to January. Nests are usually in a crevice under rocks or large tree roots, or in a hollow, fallen log. Two to four eggs may be laid, but rarely do more than two young make it to fledging.  Incubation lasts 3-4 weeks and only the female incubates eggs. Once they hatch, the male feeds the female, and she feeds the chicks. Later, the male starts feeding them directly and when they fledge after 13 weeks, the male takes over all feeding.  Some males are polygamous.

More Kea Pictures:

Links

UNL Centre for Avian Cognition – Publications of Judy Diamond.

-above link contains many scientific papers on keas and other related parrots.

University of Vienna, Kea Research Group

-Descriptions of research done on wild and captive kea at the University of Austria.

Kea Parrot Video

-Cool Youtube.com video showing some interesting kea behaviours.

Dont' Feed the Keas!
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