Q: I only have one bird, a green cheeked conure. I woke up this morning and there was an egg in the cage. How is this possible? When will the egg hatch?
-Gary M., Ann Arbor, MI
A: The appearance of an egg can shock the owner of a single bird. And why wouldn’t it? We understand that babies are the result of male and female relations. They do not just appear. The confusion seems to come from the idea that an egg contains a baby bird. It does not.
Eggs are produced by female birds in response to the changing light patterns towards the end of the winter season, slowly warming temperatures and the regrowth of vegetation. This is a signal that breeding season approaches and the endocrine system releases hormones telling the female to produce eggs because the environment is appropriate.
However, without fertilization by a male, these eggs will not hatch into chicks. The unfertilized eggs are merely a vessel which could have housed a developing bird.
The egg is perfectly designed for the task. Inside, the yolk provides a food source and the whites (albumin) surround and protect the growing chick and keeps the yolk from drying out. The egg contains its own waste removal system. The outer shell is fragile enough for the chick to dismantle during hatching yet strong enough to support weight of an adult bird during incubation. An egg is an amazing work of engineering.
How Is An Egg Fertilized?
Birds have sex to produce young just like other species of animals. However, they are equipped a little differently than many – male parrots do not have penises. Their reproductive organs are contained internally and they have an opening in their vent area like the female. In order to transfer ejaculate to the female, the male climbs on top of her back and the openings are pressed together.
It is very possible that you have witnessed your bird masturbating. It is most evident in male birds. My cockatiels will squat on their perches and switch their tails back and forth until they are satisfied. When a male is on top of the female you will see similar behavior but also a lot of wing flapping. This makes it seem like an aggressive act, but the wings are in motion mostly to keep the male from falling off.
Once the sex act is complete, the sperm travels up the oviduct tube to the ova where fertilization occurs. The fertilized ovum is joined to a yolk sac and the two travel back down the oviduct to an area where the shell is formed around them and then expelled through the chloacal opening.
The infertile egg that is produced by your bachelorette conure contains everything except a fertilized ovum.
Since the shell of the egg is comprised mainly of calcium, which is taken from your bird’s own personal calcium supply, every egg laid leaves her somewhat depleted. She will need a proper diet to keep her own calcium levels on track. You should never encourage egg laying for health reason, but if you have a female that is laying, please check out our cookbook/nutrition course for a diet that will support her through breeding season. Be sure to make the appropriate changes in your bird’s environment that make it seem a less suitable breeding environment.