Cockatiel Egg Laying, Egg Laying Process and Chronic Egg Laying
By Eleanor McCaffrey Copyright Notice: No portion of this text or photos
may be, copied, printed or reproduced for redistribution without
permission from site owner.

Why Did My Bird Lay an Egg? Finding an egg on the bottom of a bird's cage is a surprising and sometimes an alarming event for any bird owner. The surprise is even greater if the bird does not have a mate and the bird's name is John! Breeders and pet shops usually try to determine gender before selling birds based on visual clues, behavior traits or bone structure typical of male or female cockatiels. These methods are not always accurate. Your bird , who was incorrectly identified as being a male, now lays an egg, providing proof as accurate as any DNA lab test, that he is really a female. Now for the even bigger question, why did John, (who has now been renamed Joan,) start laying eggs without a mate?  There are several reasons why eggs are laid without a mate, including the fact that female cockatiels are notorious  egg layers.  Egg laying in captivity is based on the breeding behaviors and needs of cockatiels living and breeding in the wild. For wild cockatiels, egg laying and breeding are seasonal activities that only occur during the Spring and Summer months. Several changes in nature occur during these months that stimulate breeding hormones, resulting in breeding activities such as mating, nesting and egg laying. The primary influence on breeding behavior is an increase in daylight hours. Other changes include a warmer climate that is more favorable for breeding, and the availability of more rain for bathing and more food to eat. A variety of plants, grains, berries and insects can be found during the Spring and Summer months. (During the Winter months, a bird's diet is limited to mostly seeds.) Wild cockatiels nest and lay eggs inside of hollow trees, as shown in the picture to the left . Cockatiels usually mate and stay with the same partner for life.

Unlike wild cockatiel, our pet birds have a Spring/Summer like environment that provides ideal breeding conditions all year long. When something in the environment stimulates a pet bird's breeding hormones, she/he will display breeding related behavior. Females will start laying eggs and males will display seasonal aggression. Any of the factors listed below can stimulate breeding hormones, resulting in a reproduction cycle for either a female or a male bird living in captivity.

  • Exposure to increased daylight hours are caused by long hours of artificial indoor lighting.
  • Warm, indoor, environmental conditions are favorable for breeding all year long. 
  • The bird has bonded with a mirror, human or toy and perceives the object of her/his affection to be a mate.
  • An abundance of a variety of foods, including soft foods which are needed to feed chicks are always available.
  • Water is plentiful and pet birds have the opportunities to bath frequently indoors all year long.
  • The bird has been hanging out in dark cozy corners, a nestbox or birdie tents which are similar to a hollow tree.
  • The bird has paper, straw wood and other natural fiber toys inside of the cage to shred for nesting material.
  • Petting a bird on the back, stomach or under the wings (where ovary and testicles are located) stimulate breeding hormones.
Egg Laying Process: This is a very brief description of a female cockatiel's reproductive system. Adult, female parrots have only 1 ovary and 1 oviduct located on the left side of their body, under the "elbow" of the wing. Although females are born with 2 ovaries and 2 oviducts, the other ones gradually recede as a bird approaches breeding age. When females are sexually mature and something in the environment stimulates breeding hormones, hens will ovulate and start producing eggs. The yolk of the egg develops first in the follicle of the ovary. The egg then passes on into the oviduct, a long,  muscular tube that has 5 sections, each one performing a specific function. All of the other stages of development take place in the oviduct, where other  components of the egg are added, including albumin and membranes. If a male is present and a successful mating has taken place, eggs will be fertilized in the oviduct as well. Females can store sperm in their bodies for up to 15 days, making it possible for 1 entire clutch of eggs to be fertilized from 1 successful mating. 

After fertilization, the egg then moves into the 5th and last part of the oviduct, the uterus or shell gland. This is where the egg will spend the most time, from  20-26 hours. While in the uterus, a  watery solution will be added to the egg, increasing the weight of the albumen. The actual shell itself, which is composed of about 95% calcium carbonate crystals, will also be formed  around the bare egg in the uterus. The egg then passes into the cloaca and vent until it is laid by the hen. The process of egg laying, from ovary, (fertilization if male present), to development of shell to egg laying takes about 2-3 days.  If your single female cockatiel lays 1 egg, more will be on the way. You can expect your female to lay 1 egg about every 48 hours (2 days). until a clutch of 2-8 eggs is laid. Cockatiels and other parrots are "indeterminate" egg layers.  This means parrots do not lay a specific number of eggs. If an egg is lost, broken or removed, they will replace it by laying an another egg. 

Signs of Egg Laying Females getting ready to lay eggs will feel heavier, weigh more and their lower abdomen near the vent may feel firmer and look larger. When producing an egg, females will also start drinking much more water because eggs are made up of so much water.  Chewing activity will also increase, as females  start to shred more paper, perches, wood, toys etc. in preparation of a nest. Females may also  become very protective of their cage, backing up into a corner, chirping softly. Prior to and during the egg laying process, the female will have very large, loose and odorous droppings. This is also normal. Droppings are retained in the cloaca and they are eliminated by the female in the morning. A total absence of droppings indicate egg binding. Click Here.

What to do When Eggs are Laid: Do NOT remove eggs from the cage. You can place the eggs on top of a non-looped wash cloth on the bottom of the cage, or inside of a little basket, box or other container that has been lined with white paper towels. This will make your bird more comfortable and it will prevent the eggs from rolling around. If an egg breaks or your bird starts pecking at them, remove the eggs and replace them with white marbles or wooden dummy eggs. Clean the area  thoroughly to prevent bacteria from growing. Allow your single cockatiel to nest (sit) on the eggs for 21-30 days.  Cockatiels and other parrots are "indeterminate" egg layers.  This means that the species does not lay a set number of eggs. If 1 egg is lost, broken or removed, a cockatiel will just replace it by laying another egg.  If you remove the eggs, your bird will go right into another breeding cycle and start laying more eggs. This will lead to chronic egg laying. The average size clutch for a cockatiel is 2-8 eggs. Sometimes cockatiels wait until a few eggs are laid before nesting on them. So don't throw out eggs if your bird is initially ignoring them.

What Stops Egg Laying?: The hormone prolactin is needed to stop the egg laying cycle in a female cockatiel. When the first egg is laid, her level of prolactin is low. The level will increase with each additional egg laid and the amount of time she nests on the eggs.  (Source: Facts on Hormones: Exotic Bird Report, Psittacine Research, Univ. of Calif. Vol 2, Number 3.)The University of California also reported that clutch size is influenced by hormones and that clutch size can be controlled to a certain extent.  If one egg is removed from the female' s nest, 1 additional egg will be laid, increasing the clutch size.  If 1 additional egg is placed in the nest each time the female lays an egg, clutch size is reduced by 1 egg. (Source: Facts on Hormones: Exotic Bird Report, Psittacine Research, Univ. of Calif. Vol 2, Number 3.) 

Nesting Phase Care: Nesting on eggs is both physically and psychologically stressful for your bird and any type of stress impairs the immune system. Sometimes females that are nesting on eggs are reluctant to move out of the nest to eat food, drink water and exercise. Keep an extra set of food and water dishes close to your bird. Females that are laying eggs will also lose calcium. Provide plenty of extra calcium in her diet from fresh, dark green vegetables such as kale, cilantro, parsley, beet greens, turnip greens, endive, chard, mustard greens, watercress, broccoli leaves and stalks.  Also offer her bright orange foods, like baked yams,  sweet potatoes and carrots, that are rich in Vitamin A to boost her immune system. Offer her other calcium and vitamin A rich foods  as listed on this page Healthy Table Foods and this page  Table Foods. If your bird is not eating pellets, make sure she has access to full spectrum UVA/UVB lighting, 15 minutes each day from a Zoo Med or another brand of full spectrum light bulb. Birds that are not eating pellets need this type of lighting in order to metabolize calcium.  It's normal for your bird to be more aggressive with your during while nesting. She'd doing her job and protecting her nest. When the eggs are eventually removed after 21 days, the aggressive behavior subside.  

Chronic Egg Laying (Chronic Reproductive Syndrome) and Health Problems. Cockatiels living in the wild only produce 1 or 2 clutches of eggs each year.  More than 2 clutches would be considered unnatural. Chronic egg laying in pet cockatiels is described as laying more than 2 clutches of eggs per year. The stress and physical demands of excessive egg laying include some of the following health problems. 

  • Malnutrition.
  • Calcium deficiencies
  • Seizures, low calcium
  • Brittle Bones, low calcium
  • Weight loss.
  • Poor health in general.
  • Poor feather condition.
  • Feather loss or dermatitis around  vent.
  • General muscle weakness.
  • Reproductive Diseases.
  • Abnormally formed eggs.
  • Poor muscle tone of oviduct or uterus.
  • Prolapsed cloaca or uterus.
  • Egg impactions in oviduct.
  • Egg Binding.
  • Other reproductive ruptures, infections and disorders.
  • Sudden death.

Preventing Egg Laying: Avian veterinarians usually consider it safe for an adult, healthy, well nourished cockatiel to lay 2 clutches of eggs a year. Females that lay more than 2 clutches of eggs a year are considered chronic egg layers,  having a condition which avian vets refer to as Chronic Reproductive Syndrome. In most cases, chronic egg layers will seem healthy for years but eventually they will suffer from malnutrition and other serious health problems because of the progressive stress and physical demands associated with egg laying. Stress impairs the immune system, making it easier for birds to get sick. Egg laying in excess of 2 clutches a year should be discouraged because it also compromises a female's general health and causes reproductive disorders. Once a female starts laying eggs, all future egg laying is influenced and controlled by hormones. By interrupting, changing and removing the environmental stimuli that cause a hormonal egg laying cycle, future egg laying can be prevented. Environmental changes should create undesirable breeding conditions, just the opposite of what optimum conditions are for breeding.

 Modifying your Bird's Environment: (also for male, seasonal, hormonal aggression) Remove birdie beds and sleep tents from the cage. Remove cage mirrors that your bird seems overly attached to and toys that she/he may be using for masturbating. Remove toys made out of paper, wood and other natural fibers that she is chewing and shredding. Re-arranging the cage so it feels less secure and reducing the number of daylight hours your bird is exposed are often very effective in preventing or stopping chronic egg laying. Birds will not set up nest and start producing eggs if the site they have chosen feels insecure. Re-arrange, switch and move perches, feeding dishes and toys or replacing them  with new items that are a different size, color, texture or shape. Other changes that can make the cage feel less suitable for nesting include moving the cage to another area side of the room or moving cage into a completely different room.  Putting your bird into an entirely different looking cage in a different room is even better. The more drastic the change, the more effect it will have on preventing egg laying.  Since exposure to daylight has a strong influence on breeding hormones, reduce the amount of daylight hours that your bird is exposed to so the environment resembles Winter, non-breeding months. Reduce daylight exposure to 10 hours a day and keep the cage covered for 14 hours each night in a very dark, quiet room, for 2 weeks. If this doesn't help, reduce your bird's exposure to daylight to 8 hours a day Cover the cage so your bird is in darkness for 16 hours for 2 weeks. Avoid giving your bird baths, water misting or soft foods during the 2 week period. After 2 weeks resume  normal bathing and feeding routines. Note: Re-arranging, moving the cage and reducing light should all be done at the same time. Reducing light alone may encourage egg laying by making the cage seem like a nestbox. (The same suggestions work for males that are going through seasonal aggression.)

Dark, Cozy Corners and Petting Effect both Females and Males: The presence of an acceptable nesting spot and nesting material always encourages breeding behavior. Both female and male birds will seek out dark corners. Females will lay eggs and males will become very territorial and aggressive, often attacking and biting you to protect the spot they have found. The space in-between the bottle and microwave, in the photo to the right is a good example of the type of area that encourages egg laying and breeding behavior. If you notice your bird investigating dark, enclosed areas like cabinets, open bureau drawers, the top of closets, the inside of shoes, socks etc. don't allow it. Close, block  or cover the "entrance" because your bird is probably looking for  a place to lay eggs. Cockatiels do not need an actual nest to lay eggs in. They just need a cozy, little out of the way corner, like the one the bird in this picture has found. It's not uncommon at all for cockatiels to lay eggs under chairs, under beds or other out of the way places in the home where they are allowed to spend time. Sleeping tents, huts and birdie beds that are sold in stores also provide a place for egg laying so  avoid using them with cockatiels as well. Last but not least, Avoid petting your bird on the back, stomach or under the wings because that's where a female's ovary and a male's testicles are located.  When you show your bird affection in these areas, you're  stimulating her ovary or his testicles.

Hormones & Surgery: If your bird continues to lay more than 2 clutches of eggs per year despite all of the measures presented, take her to an avian veterinarian. Lupron, a prescription hormone therapy is available that may help your bird. Another method suggested, (when all other methods fail and when the hen is still in good health), is to allow the female to raise 1 clutch of chicks. This may end  chronic egg laying. As a last resort, an avian vet may recommend that a chronic egg layer have a hysterectomy to prevent  egg laying. An avian hysterectomy is the removal of just the 1 oviduct, not the ovary. Most of the egg's development takes place in the oviduct and the ovary is located near a very large artery which would make the procedure too risky. 

Click Here to read about Egg Binding. It may save your bird's life.  Note: Replace toys that are used to chew on and shred after egg laying or male aggression has stopped. Your bird needs these types of chew toys to prevent  boredom and feather plucking


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