Two clutches a year is not particularly alarming. It’s one more than she would have in the wild each year, but she doesn’t have the strain of feeding chicks each time. It’s fine to remove the eggs once she loses interest, even if the incubation period is not over. However, Marley is showing signs of nesting again already, and this can turn into a chronic pattern if you do not make some changes. I’m also a bit concerned that you say she is straining. It might be a good idea to take her to an Avian Vet to be checked out.
I personally am not a fan of night cages unless it is a situation where the bird would be exposed to noise and light during the night if in the main cage. In the wild, adult birds do not sleep in or use a nest except during breeding season. Most species sleep in a high tree, many with flocks for protection in numbers. I recommend a high perch for them to feel secure, with some toys near it to provide some feeling of protection. Covering the cage is generally not necessary, although some birds like a cover and a cover can help when you are trying to reduce their light exposure to prevent hormonal behavior like egg laying. Anything else starts to simulate a nest, and Marley clearly views her night cage as a nest. With the smaller size and by also covering the cage, you have inadvertently created a cozy nest for her and this is actually encouraging her to lay the eggs. So the first change would be to phase out the night cage and let her get used to sleeping in her main cage.
We recently hosted two webinars on pet birds and hormones and I will provide those links below. Ideally you want to prevent or minimize hormonal behavior and egg laying by avoiding common triggers. We have learned that when petting your bird, it is best to stick to head and neck scratches. This is particularly important for Cockatoos because they will engage in cuddling much more than other species. However, their hormonal behaviors can be among the worst with the males becoming dangerously aggressive and the females becoming chronic egg layers to the point of dying. I know how wonderful it can be to cuddle a cockatoo, but for her well being, you need to reduce the body petting and get her to the point that she only expects head scratches. I will keep mentioning wild birds, because the advances made in understanding pet bird behaviors is based on knowing the behavior of their wild counterparts. Our pet birds are after all captive bred wild species and not a domesticated species like dogs and cats. So in the wild, young birds live in flocks and engage in mutual preening which is limited to the head and neck. Only when they bond with a mate will they allow the mate to preen and groom the entire body and from the time that they bond with a mate, physical contact with flock members ends. When we pet a bird all over, we send the message of being a bonded mate but of course that is not the case. But hormones are triggered and the bird becomes frustrated with the human.
Birds will breed when the weather is warmer, days are longer, food is abundant and there is a safe place to nest. Since we provide all of these things all year, birds can get in a chronic state of being hormonal. To avoid triggers, when the weather warms up, try limiting her daylight hours to 8-10 per day – cover her cage early in the evening if you have to. But again, I mean the main cage and not a sleeping cage. Limiting the daylight is not enough, and may not be effective at all, but when avoiding the triggers, you may as well try everything. More important is the limited petting and the rest of the triggers. Do not provide anything that can be viewed as a nest, no boxes, no dark places to hide in the house, and nothing that can be shredded and used as nesting material. Shredding can be a big issue with cockatoos since they so love shredding things. But you can stop providing these type toys except for occasional play. Limit any fresh foods or table foods offered to just a small amount a couple of times a week when the days are longer or if she shows signs of wanting to nest. For some birds, it even helps to rearrange the toys and perches in the cage once a week and move the cage to another place in the room. This tells them things are changing and not stable enough for breeding. When she does get cuddly or acts hormonal or broody, try to divert her attention to a toy or an activity like trick training. As a last resort, there are injections or implants that can help, but this can be expensive and any medication carries risks. So it’s best to try not to get Marley to that point by making changes and removing hormonal triggers in her life.
Please check out both parts of Dr. Lamb’s webinar on hormones – she goes into much more detail and has some great suggestions.
Webinar: “Spring Is In the Air: How To Deal With Your Pet Bird’s Hormonal Behavior!”
Webinar: “Pet Birds & Hormonal Behavior: Part 2!”
Thank you for asking Lafeber,