Abstract
Male aggression is probably the most devastating problem in the breeding of cockatoos. It is a chronic and distressing challenge that has caused many exotic bird breeders to abandon their efforts in cockatoo breeding, and sometimes to abandon their efforts in aviculture altogether.
Male aggression is not exclusive to newly introduced pairs. This behavior frequently occurs in pairs of cockatoos that have been housed together, breeding successfully, and producing offspring for a number of years.
There are many theories as to the cause of male aggression. Aviculturists have developed various theories regarding placement and size of the breeding cages and breeding boxes over the years. Hormonal changes and incompatibility are frequently blamed, as well as considerations of dietary changes and even jealousy. No one has yet come up with the answer, and Mother Nature is not talking
Male aggressive behavior can have a sudden onset, or it may be subtly progressive. Sudden onset is the most heartbreaking, as the male and female
may be cuddling in the afternoon, and then she is found dead in the cage or nest box the following morning. This scenario occurs suddenly and without warning. It is more common in pairs that have been together for a long time, and the male has never shown signs of aggression towards the female.
In cases of progressive onset, the first sign is often when the female is observed to be spending most of her time sitting on the bottom of the cage. The male may chase her into the nest box frequently, or may chase her away from the food dish. He often exhibits a restlessness or agitation. He may crouch down frequently, rocking from side to side with his wings trembling, and making unusual puffing or squeaking sounds. Injury to the female usually follows soon after.
The resulting injury to the female may initially appear minor, such as a spot of blood above the beak or a spot of blood on a wing. Within a few hours, days, or even weeks, the female will most likely exhibit more severe injuries, most commonly facial, beak, and foot lacerations, and broken wings. There are often holes in the mouth that have been undiscovered until a vet exam because the apparent injury appeared to be a simple bite to the upper beak. In most cases, the male will eventually severely mutilate and kill the female if intervention is delayed. Once a male has exhibited physically aggressive behavior causing injury to the female, he can be expected do it again to the same female and to another. He cannot be trusted, even if he temporarily appears to have settled down. Preventive intervention is mandatory at this point.
My experience has been that the most frequent occurrences of male aggression in the cockatoos have been in the months of February through May, which is actually the height of breeding season in southern Florida. There have been less frequent occurrences in all other months. Interestingly, nearly all the female injuries have occurred three days before through three days after full moon.
There has been a low incidence of
male aggression in my wild-caught breeders. The handfeds have exhibited an alarmingly high incidence of aggression. They seem to have no fear and no conscience when it comes to beating up their mate. The pairs in which a wild caught male is with a domestic hen have shown the least incidence of aggression, followed by the pairs in which a domestic male is with a wild caught hen.
The most frequent incidences have been in pairs where both are domestically bred handfeds. Most of my breeder pairs fall into this category, hence the high frequency of aggression. It has also been observed that the second and third generation handfed males are more aggressive than their fathers were.
Through the years, there have been many attempts at dealing with male aggression. My avian veterinarian, Susan L. Clubb, DVM, Diplomate ABVP-A vian Practice, has developed a number of methods of combating the problem, and I have been fortunate
enough to put them into practice. In addition to trimming the wings and nails, several other physical means have been used.
The first method we tried was using a "beak ball" which was an acrylic ball attached to the upper mandible. This was basically unsuccessful, as it fell off after a few days or weeks. A surfboard bumper, which was also attached to the upper mandible, was then tried and also fell off shortly after its application.
During the past two years, we have had to develop a more reliable method of dealing with the problem. A procedure was developed and termed "disarming" by Dr. Clubb. I would like to make it very clear that I would not use such strong measures with my birds unless it was absolutely necessary and I would not use anything that would impair the well being of the birds. These birds are my babies; and I would never do anything to harm them.