Q: I have a breeding pair of cockatiels. They just laid an egg last night, but this morning the male is sitting on the egg and won’t allow the female in to the nest box. When she tries to enter it, he bites her and chases her out. Is this normal behavior? Should I separate them? If I do, will she continue to lay eggs or care for them?
Linda S. Rubin explains:
It’s possible that this pair of birds did not successfully bond before laying eggs. Although most cockatiel pairs will commence nesting activities within the first 10 days of being introduced, there are exceptions. Overly aggressive males, caught up in an onslaught of hormones, can fly or chase after females, seriously harming them. Although this is uncommon, it is prudent to remove the male to avoid his eventually injuring the female, or worse. Some male cockatiels will become agitated or aggressive if they can still see or hear their previous mate while paired with another female not of their choosing. In rarer situations, overactive hormones may make some males dangerous to all, even to other males who they may injure out of frustration to drive them to nest or to begin a new nest without yet completing the first. It is best to separate these aggressive males until their hormone levels return to normal after a long rest. They may be reconsidered in the future, especially if repaired to a different female and a new pair bond is created.
Because the female is interested in sitting the egg and the male is not allowing her to enter the box, remove the male to another cage or pen. This will allow the female to sit, but remember, a single bird doing all the sitting can easily become overtaxed. Some females may not wish to leave the egg in order to properly feed, drink or eliminate. The male normally relieves the female in the morning and early afternoon to allow her time to complete these activities and rest. Although some aviculturists artificially incubate eggs and hand-feed chicks from day one, success rates are low and not recommended for the inexperienced.
Assist single cockatiels sitting eggs by positioning foods within easy reach inside the nest box. Sitting cockatiels expend a lot of energy maintaining the temperature of eggs, resulting in a drain of energy and fat reserves causing weight loss. Provide plenty of cuttlebone, supplemental conditioning and soft foods and observe carefully. Expect your hen to lay additional eggs to complete her clutch. Never remove the eggs, because this will cause her to lay more to replace those that are lost. When your cockatiel is ready, she will abandon them on her own, or once they are well beyond the expected hatch dates of 18 to 22 days, depending upon when she first begins to sit.