Hi Heather,
Are these birds tame at all or are they only bonded to each other? Generally, when birds care caged together, they will end up bonding. If this is a male and female, they most likely have a mate bond. If this is the case, the male will tend to want to protect the female and keep any rivals away. It sounds like you are not usually home, so it may have disrupted their routine. He may have felt you were a threat. If a male can’t drive a rival away, he will turn on his mate and bite at her to make her retreat. Birds can get confused in captivity because of having to share space with humans and other pets. If he is hormonal at all, this can make him more aggressive. Since she is not physically sound, he may feel she is a threat to his safety. Flocks will shun injured or sick birds because it makes them vulnerable to predators. So it’s hard to know exactly why he did this, but the question is if he is bullying her a lot. If he isn’t pulling out her feathers or drawing blood, then harmless squabbles are normal. You can do things to help her get around better. There are flat perches you can order to give her a wide surface to stand on. There is also a product called Vet Wrap that you can wrap around the perches to give them some texture and help her grip. This does get soiled and has to be replaced often. They also make shelves for pet birds. Mainly do not get anything with a top or sides, because you don’t want her to view it as a nest. Even a platform can be viewed this way, but it doesn’t hurt to try to give her a better place to sit. If he gets too aggressive with her, you may have to split them up and let them be in cages side by side. Nanny or web cams are affordable these days, so you might set something up to observe them so you can see what they do when you are away. You do not want him to start trying to mate with her. She would have problems trying to lay eggs, so avoid anything that could make them want to breed – this includes no nests or huts and nothing they can shred.
Thank you for asking Lafeber,
Brenda