This is a question I hear via email and through the forums all the time! Most owners are surprised to learn that their sweet little "Sunshine" (often believed to be a male!) can lay an egg often without the benefit of a mate in the same cage! But single parrots, large and small, can indeed lay an egg or two (or 6!)
This is more common in some species of birds than others. For example, cockatiels and lovebirds seem particularly prone to chronic egg laying. Smaller birds tend to do this more often than the larger parrot species, maybe because they have grown more accustomed to breeding in captivity.
As the owner of a single bird that just laid an egg you have every reason to be a bit worried. For one thing, continual egg laying can sometimes lead to calcium deficiency and/or egg binding (that is when the hen can't lay the egg because the shell is malformed or too soft from lack of calcium.) . Either one can be really dangerous for the her and can even lead to her death in some cases. That is why bird breeders always supplement their birds with calcium during the breeding season.The other thing that happens during egg laying is that hens will often become aggressive when the hormones that trigger breeding kick in, and they become overly protective of their eggs. ( Think feathered piranha!) Fortunately, Your sweet "Sunshine" usually reappears once her egg laying cycle is over.
In order to try and stop your bird from laying eggs, it helps to understand what can trigger it! There are certain things that help bring a bird into "breeding condition" so that she begins producing eggs. In the wild these things include the lengthening of days, the rainy season, and the availability of certain foods with which to feed their young. Breeders often work very hard to get these conditions just right to help their birds begin producing eggs. When a bird goes into breeding condition, hormones are released that start the cycle of producing and laying eggs.
So when breeders want their birds to start laying, they gradually increase the number of hours that the birds have light, increase the availability of fresh foods and increase the amount of rainfall (or baths). I've found that if a pet owner does just the opposite, it usually stops the egg laying cycle or prevents it from starting altogether.
For owners who want to be try and stop it before it starts, or at least decrease the chances of their single bird ever laying eggs, I recommend no more than 10-12 hours of light each day. In all but the most stubborn birds, this will be sufficient to prevent the onset of egg laying.
To try and stop egg production that has already begun, I would suggest immediately making her days shorter by turning out the lights after a 8 to 10 hour day. Also, I would stop giving daily baths (try to use a drinking fountain instead of a water bowl as most small parrots will happily bath in their water bowls) and cut back on fresh foods. I would also immediately begin adding a calcium supplement to the bird's diet. Once the egg laying has stopped, regular bathing and fresh foods can resume, and you can slowly increase the amount of light to 10-12 hours a day. But keep a close eye on things and switch back to shorter days and fewer baths if needed.
Special note about lovebirds: Lovebirds actually line their nests with bark and leaves in the wild. In captivity they happily make do with their paper cage liners. Try switching to some sort of particulate bedding on the cage bottom to prevent her wanting to tear strips of paper and tuck them under her wings to carry back to her nest. Aspen shavings, or corn cob bedding work nicely. What ever you do don't let her near the phone book!!!Also try to totally change up the layout of your bird's home. Redecorate by moving the perches around, or even better replace them with new different styles of perches. It helps to have a couple of different sets of perches in a case like this. Then you can switch things out every week or so, to keep her guessing! Try the calcium perches, rope perches, manzanita perches, regular dowel perches of different diameters, check out your local bird store or even places online that carry a good supply of bird products (like drsfosterandsmith.com) Try to have a variety to switch in between. Also keep her toys on a constant rotation, and always in a different place within the cage. The idea is to keep her so busy exploring all of the new fun stuff that she doesn't have time to concentrate on wanting to breed!
Every once in a while, a hen will continue to lay egg after egg even when the above steps are taken. If this happens with your bird, you should discuss the situation with a good avian vet. It's possible that the vet will suggest a hormone shot to get the egg laying stopped.
Finally I am always asked "but what about the eggs?". Everybody has their own ideas about this, but I would probably throw the eggs away, and try the things I suggested above. However if you choose to leave them and allow your hen to incubate, after a few weeks to a months she'll usually loose interest in them and go one with her life as normal. But be sure to change things up some or she'll just assume that batch was full of "duds" and start laying all over again! One more thing to consider, if you do remove her eggs and leave everything else the same, often instinct kicks in to replace her lost egg, which can only make the problem worse. Some people recommend taking the eggs as soon as they are laid and then following the advice given above to try to stop the egg laying cycle. Some feel that removing the eggs upsets the bird, but I have never noticed that to be the case when I've removed eggs in the past. However, you should listen to both sides and do what you feel makes the most sense for your parrot, just like anything else the choice is yours to make.
I hope that helps some of you! I'd love to hear your comments with your experiences in this matter.
