Ask Lafeber

Aggressive Male

Male cockatiel is being very aggressive with female now that I put the nesting box in. He bites her and throws her down

Hi Eliana,

I would remove the nest box immediately. This is extreme aggression and it it continues he is going to kill her. If removing the box stops the aggression then they can stay together. If he continues to be aggressive towards her, split the pair up for now.

As far as why, it can be hard to know why a male does this, but it isn’t uncommon in captive breeder cockatiels. Are your birds old enough for breeding? The female needs to be at least two years old, and the male should be 18-24 months old. Breeders who breed cockatiels for shows usually do not pair birds up until both are at least 2 years old. While they may be sexually mature at a younger age, they are still developing emotionally, so a young bird is more likely to only want to mate, but not settle down and care for eggs or chicks. If your male is older than the female, this could be the issue, especially if she isn’t 2 years old yet. He may be ready to breed, but she isn’t. In that case, wait until she is older and try pairing them again. A pair should be well bonded with a mate bond before you give them a nest box. The pair should be spending most of their time together, preening each other, sometimes feeding each other and sitting together. Once you observe them mating, you can give them a nest box. If the pair isn’t fully bonded and you give them the box too early, this can cause the type of aggression you are seeing. A pair that doesn’t sit together, has spats, even if they are harmless, and argue vocally – lots of squawking, rather than friendly chirps – these are signs that the pair isn’t compatible. In the wild, birds get to choose their mate. In captivity, they do not always like the mate we choose for them. Not all birds make good breeders. Some males are aggressive to the female whenever a nest box is introduced. Some males can become aggressive and territorial towards the female after the eggs have been laid or even after the chicks hatch – even if the pair got along to that point. These are all signs that the male is not suitable for breeding. It’s also very important that the birds are on a nutritionally balanced diet such as pellets or our foraging diets. A loose seed mix will not provide the nutrition they need for laying eggs and raising chicks. You should also offer dark leafy greens and chopped veggies. And when they are breeding, they need cooked eggs with the shell washed, crushed and cooked with them – this provides extra protein and calcium the hen needs for laying eggs and feeding her chicks. The breeding cage needs to be large enough for them to fly, and in a quiet, private place where they do not see humans other than when you feed on them or check on them. If they are in a busy part of the house, the male will feel threatened and this can cause him to attack the female.

If you have met all of the criteria – the birds are old enough, bonded as mates, good nutrition and a private place for the cage – then you can try giving the box back to them to see what happens. But if he attacks again, then this pair should not be bred. You can try getting another male, but you would have to find a new home for the current male. The hen might not accept a new male if she can hear the other male.

Thank you for asking Lafeber,

Brenda