Cockatoos aggression – possibles causes and solutions. PART II

March 11th, 2015 | by Tony Silva
Cockatoos aggression – possibles causes and solutions. PART II
Tony Silva NEWS

Read also the first part of this article:

Tony Silva NEWS: Cockatoos aggression – possible causes and solutions. PART I


Placing a ball on the tip of the bill has also been tried, though the beak continues to grow and the bumper (made from dental acrylic) eventually falls off. The solution (like clipping the flight feathers) is temporary at best.

Some males can be especially treacherous and cunning. I have seen cases where a male changed his attitude overnight. From being especially aggressive, he switched to a placid bird. I was optimistic the first time I made this observation as the male was repeatedly seen perching and feeding the hen. Then slowly his plan came to light. He began to remove the flight feathers from the female, this to incapacitate her. This process took days. I watched closely. Then he became a demon and would have killed the hen had someone not been nearby to interfere. She nonetheless suffered several puncture bites—one to the beak and two to the wings. The female recovered. Subsequently I watched the same behavior in other males, suggesting that the first incidence was not isolated.


File:Eolophus roseicapilla -Wamboin, NSW, Australia -pair-8.jpg

Not all of cockatoos are aggressive – Galah Cockatoo. (c) David Cook. This file is licensed under the Creative Commons Attribution 2.0 Generic license.


In another case, a male with an acrylic bumper attached to his bill, flew at the hen, grasped her with his feet and then frantically hit the female on the head. He could not puncture her beak but caused injuries from the repeated blows.

The above incidences have demonstrated how intelligent and cunning cockatoos can be.

Flying pairs in groups after the breeding season can also have a calming effect. I have found that same sex groups are best, as males can and will fight with one another. How the groups are kept depends on the individual birds. I have some Medium Sulphur-crested and Moluccan Cockatoos that I can keep together and others in which more than one male will result in explosive battles. I decide how they are to be housed depending on the experience gather over time with the individual birds. As the breeding season approaches—in our case winter and spring, the birds are separated in the summer—the pairs are returned to their cages. I often add one male at a time to a cage containing females, including his former mate. This allows me to provide the mate of choice. In 37% of the cases, the males chose new mates and do not re pair with the hen with which they bred successfully the previous year. Studied in Australia have shown an equally high incidence of divorce in wild cockatoos.

READ  Tony Silva NEWS: Questions and answers. Why are my budgies still getting smaller and have poor reproduction results?

Due to the continuation of problems of mate aggression being reported, other solutions were thus needed and one was proposed. Dr. Scott McDonald developed the most contentious method of controlling aggression: beak-bisecting surgery. It involves splitting the lower mandible on the male. This eliminates the crushing strength. The birds can eat normally, but some will require periodic catching to cut the bill, which can overgrow. Though controversial and the procedure was eventually recanted by Scott, I know of no incidence of a male with a bisected bill being able to injure a hen.


File:Salmon-crested Cockatoo 045.jpg

Moluccan Cockatoo represents one of the most aggressive cockatoo species (c) Ltshears. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.


The above summarizes the cause and methods used by aviculturists to address mate aggression. But none focus on the reason as to why males aggress their mates? Is there a behavioral aspect that we have failed to understand? I believe so. My theory is not etched in stone and will probably be modified over time. My current state of thought is enumerated below.

During more than 40 years as an aviculturist, I have bred nearly all of the cockatoo species and subspecies. I have also spent considerable time visiting aviculturists worldwide and observing these birds in the wild. Isolated observations were noted and then placed in the back of my mind as isolated. Today many of these thoughts have been meshed into a theory.

Thailand once had a very active trader by the name of Daeng. He kept a flock of Indonesian cockatoos in an aviary. The birds bred very successfully. I had forgotten this until Don Wells mentioned it during a lecture I gave at AVES convention in Australia in 2013. I immediately flashed back and recalled seeing multiple males threatening each other with wings open and crest raised; they screamed and lunged. I asked Daeng if he ever recorded an injury. He shook his head in the negative. He then had an employee open nest after nest and show me the contents: eggs and chicks. The birds were breeding successfully in a colony—a situation that many would think would result in complete failure. I asked if egg breakage was a problem. Again the response was in the negative.

READ  Q & A: "Can parrots be bred successfully indoors?"


cacatua Tony

Cockatoos chicks (c) Tony Silva


William Peratino has been breeding Moluccan Cockatoos for many years. I first met him in the 1980s. I recently asked Will about his method of breeding. He keeps them in a group and when two birds pair and want to nest, they are separated into a breeding cage, though the males can see and threaten each other. Another friend who wishes to be unnamed maintains a flock of Major Michell´s Cockatoo in a lanai. The group contains 11 females and 7 males. The majority are offspring of two original pairs. The cockatoos breed in ceramic jars placed between low growing plants. The males become especially garrulous when nesting, when they will chase and mock battle or perch in a central metal beam and lunge at each other. The fighting can seem vicious, though not once has an injury been recorded. The hens are relegated to the incubation process while the males spent energy in their battles. Each year young fledge into the group. Not one chick has ever been injured, though the literature contains many reports of male cockatoos attacking their male offspring when these fledge.

Observations in the wild also suggest that males may behave like my friend´s Major Mitchells or Daeng´s cockatoos. They may spend time displaying and chasing each other, often in a central tree, while the females carry out most of the incubation. I have observed males of several species sitting on an emergent dipterocarp on more than one Indonesian island. The birds would suddenly suspend themselves, flap their wings and call, then spring upright and fly at another male. The two would scream, lunge at one another and often fly away a short distance before returning. I have observed contact on more than one occasion, but through binoculars could not observe any injuries. On each occasion multiple males gathered to display. Interestingly at the time hens were found incubating eggs.Bonnie Zimmerman, who has actively studied cockatoos in Indonesia and has more experience with wild Moluccan Cockatoos than anyone I know, has also observed displays in a central treeand chasing.

READ  Tony Silva: Parrot Hand-feeding. PART I


File:Cacatua goffiniana -captive-8a-3c.jpg

Ducorps Cockatoo (c) Sam Mugraby. This file is licensed under the Creative Commons Attribution 2.0 Generic license.


The incidences of mate aggression in the wild have occurred in areas where the forest was greatly disrupted as a result of deforestation or trapping was occurring. Such activity, I believe, could have contributed to the aggression. Clearly much more data is needed to provide clarity to this enigma.

Could the inability to display and venting of aggression towards one another be the reason for the aggression in captivity, where the tendency is to keep pairs isolated visually? Could the incidences of injury be lessened if pairs were kept in a large enclosure with access to attached flight cages for breeding? Could the solution be in the way cockatoos are managed and not in trying to adapt a behavior by clipping the flight feathers or bisecting their beak?

I do not have the definitive word, though my current thinking is to allow pairs to visualize groups containing both sexes, to pair only birds that have nexused from a group, to give each bird the opportunity each year to switch mates if they so desire, and to continue to gather data.



We are in the process of acquiring a piece of land to house the cockatoos so that various ideas can be put to practice. One will include a large flight containing multiple pairs. That cage will contain a maze giving access to breeding cages. Observations made here and gathered over the next few years will, I hope, clarify further the complicated personalities of cockatoos.

In the mean time, share and publish your findings. By combining the observations of many, we will begin better understand a group that in the case of the species from Indonesia and the Philippines face a very uncertain future in the wild. By managing our captive birds, we can work towards establishing captive self-sustaining populations and at least maintain these birds for posterity.


Title photo:  (c) Tony Silva


   Send article as PDF   


  1. Pingback: Tony Silva NEWS: Cockatoos aggression – possible causes and solutions | Parrots Daily News

  2. Ralph says:

    “I know of no incidence of a male with a bisected bill being able to injure a hen” – I hate to say this is not true. I purchased a pair of major mitchell’s, the male male had a bisected beak. They were fine for the previous breeder, but the first season I had them, the male attacked the female quite viciously and she ended up with a comminuted fracture of the right wing. Unfortunately, she died during surgery.

  3. Michael Chaitin says:

    Great article. I have 36 years experience with multiple cockatoos, (45 years with all my parrots). I have never had a breeding pair nor would I consider a male and female of the same species. They get dangerous enough when hormones start flying around.
    Thank you for your hard work and dedication.

    • Bashi Hazard says:

      Hi there,

      We would love your thoughts on this. We were just offered a baby male black cockatoo (he is about 8 months) as his first ‘dad’ passed away unexpectedly. We already had a baby macaw on order – have been waiting for her for a year. We would like to bring both into our home at the same time so they are not competing with each other later on. Not for breeding but as pets. We would truly appreciate your thoughts on whether we are doing the right thing. Yes, we have other birds but not of this size that will be kept separately. They are flighted and trained.

  4. A very good article. Something I will definitely consider in setting up cockatoos for breeding. I, too, had a Ducorp male with a dissected bill who actually killed his mate. Very sad.

  5. Hi there to every single one, it’s genuinely a good for me to go to see this web page, it
    consists of important Information.

  6. Martina says:

    There are plenty of sites that you can visit to idftiney your bird, as without a picture every one is stabbing in the dark.Now you identified it as a Galah, then it’s natural foods are Seed, Tree bark and Leaves,wild seeding grasses , fruit and any other plants .Also Seed is the natural food of any Parrot or Cockatoo along with various veg. and fruit. in correct portions, As breeder of various species over many many years I always fed my birds on natural foods , never artificial such as Pellets.(harley drive is correct)Birds only get problems if the are fed incorrectly and the wrong the case of Galah’s Peanuts are the main cause of fatty tumors.and over feeding of fatty seeds.Natural is always best Pellets can cause more problems than you seem to be aware of.

  7. Kathy Heaton says:

    Hi Tony,

    Very interesting and informative article; however, I’m unfamiliar with the word “nexused” that is found here:
    “I do not have the definitive word, though my current thinking is to allow pairs to visualize groups containing both sexes, to pair only birds that have nexused from a group, to give each bird the opportunity each year to switch mates if they so desire, and to continue to gather data.”

    I think you mean two birds that have selected each other for mates (possibly re-pairing from a prior bond) and separated from a flocking group, seeking a nest site? I don’t know a word for that, either; neither recuse nor excuse is correct. But the concept of a no-fault divorce is appealing. The first male Moluccan I ever met was presented as a “vicious wife-beater” for murdering his original mate (with whom he’d successfully bred in previous seasons.) I don’t know if he ever found a new home/mate…

    Please define “nexused” to me? Thank you for sharing your time and expertise.

    • Kathy Heaton says:

      Tony responded privately:
      “It’s a biological term for pairing from a group. Glad you liked the article.”

Leave a Reply

Your email address will not be published.

Parrot News Blog | Parrots Daily News