Whether you care for birds in an aviary, breeding situation, exhibit, or in your home, aggression is a problem that can affect everyone. Aggression on some levels is a normal, natural behavior. Famous behaviorist Konrad Lorenz noted that most animals have some degree of aggressive repertoire. Have you ever witnessed the undeniably distinctive aggressive strut and eye pinning exhibited by a territorial Amazon parrot? This can be a very clear indication that its territory is currently off limits to all trespassers.
What is interesting is that chemical reactions are taking place in bodies of these birds just prior to exhibiting aggressive behavior. In short, an external stimulus causes the bird's body to produce adrenaline, which in turn leads to the observable behaviors we see.
What is important to note is that more than likely, some aggressive behavior is part of a bird's survival strategy. Certainly it makes sense for a bird to aggress to defend its nest site, mate, or offspring. Varying levels of aggressive behavior also enable a bird to obtain food and other resources, and defend itself if necessary. In other words aggression does
serve a very important purpose in a bird's natural history. Additionally, a successful aggressive event can be quite reinforcing for the "winner" of the altercation. This teaches an individual that it is good to "win." Losing can result in many unwanted outcomes. A bird may lose its territory or resources, or have to endure unpleasant circumstances. Winners may look for more opportunities to be aggressive, while losers may avoid contact with an aggressor in the future.
Types of Aggression
Respected marine mammal trainer Ken Ramirez ( 1999) categorizes aggression as reactive (this is usually in response to force), innate (this is preprogrammed responses, like a territorial Amazon Parrot) or learned (this occurs when aggression has been reinforced). Within these broad categories are even more specifically defined types of aggression.
These types of aggression are as follows:
Physical State Induced Aggression Displaced Aggression
Possession Aggression or Resource Guarding Aggression
Excitement that Turns into Aggression Social Aggression
Learned by Practice Aggression Frustration Aggression
behaviors can blur into other categories. For example, aggression that may have begun by reactive or innate responses can evolve into learned aggression.
Punishment and its Drawbacks
Often humans resort to punishing methods to decrease aggressive behavior. Punishment is defined by applied behavior science as a strategy that occurs after a behavior has been presented and is meant to decrease that behavior. Quite often, the application of an aversive or negative experience for the one being punished is involved as well. While at times punishment can be effective, the drawbacks to using punishment are often greater than the benefit. These drawbacks include the following:
• Because punishment happens after the behavior occurred, the subject cannot change what just happened, only future events.
• If punishment is not in direct conjunction with the undesired behavior, the bird does not understand what behavior is being punished.
• The punishment is associated with the punisher.
This can damage the relationship between the person and the bird.
• Because punishment is not very effective, there is a tendency for the punishment to escalate.
• Birds can learn to mask aggressive body language to avoid punishment.
• The undesired behavior may return if it is only punished occasionally.
Modifying Aggressive Behavior
Instead of resorting to punishment to modify undesired behavior, behavior science provides other options that do not rely on negative experiences to obtain desired behavior. The following ten suggestions are a compilation of work done by various researchers on how to address aggressive behavior. In many cases utilizing a combination of the various strategies can address aggressive behavior.
1. Keep notes on aggressive behavior to help identify the cause of aggression.
2. Avoid circumstances that elicit aggressive behavior.
3. Do not attempt to "work through" aggression with punishment or negative reinforcement.
4. Divert the attention.
5. Do not accidentally reinforce aggressive behavior if possible.
6. Reinforce any behavior other than aggressive behavior.
7. Teach cooperation with small approximations and positive reinforcement.
8. Teach an animal to do behaviors that are incompatible with aggression.
9. Use repetition of a simple behavior to reduce aggression.
10.Put the aggression on cue, and then never ask for it (less recommended than 1-9).
The following are a few examples of how the strategies listed above can be used to address aggressive behavior.
Parrots in a Sanctuary
Aggressive behavior: Many of the birds bit at hands when presented for the behavior of "step up". (Step 1)
Aggression type: The aggression was probably fear aggression based on previous negative experiences with hands. More than likely, force (negative reinforcement) was used to attempt to train the birds to step up onto hands. The birds responded with aggressive behavior at the sight of hands nearby, therefore the birds had also likely learned aggressive behavior would potentially keep hands away (Step 1 ).
Solution: The decision was made to train the birds to step up onto the hand for positive reinforcement (Step 8). In separate training sessions, each bird
was lured out of its enclosure onto a small perch with food reinforcement. Once on the perch, the cage was rolled away to avoid territorial aggression (Step 2). A hand was rested on one end of the perch away from the bird. The bird was lured closer to the hand with food and positively reinforced for any action of moving towards the hand (Steps 2, 3 &7). The slightest display of aggressive behavior was addressed by using a "time out." This involved removing the hand from the perch and the hand with the food items from the vicinity.
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