Q: We have a pair of well-adjusted green-winged macaws (Ara chloroptera) set for breeding in our living room. The female is now laying eggs, but the male eats them as soon as he gets the chance. He puts a hole in one end, holds it up and lets the fluid from the egg slide down his throat. She has laid nine eggs, and he has stolen all but two that I managed to get to first. We tried filling a hollow egg with mustard to discourage this behavior. He stole the mustard egg, and when he tasted it, he spit it out. Will this help?

Also, is it okay to give them powdered milk in their water as a calcium supplement? They get a breeder pellet, broken up cuttlebone and a mineral block to give them adequate calcium. I’m worried that after laying nine eggs the female might need a little extra calcium.

A: Although your pair of green wings appears to be well adjusted to life in the living room, the male’s strange behavior might well be caused by the cage location. This, of course, is beside the point at hand.

Birds that break their eggs due to some type of resented interference can often be cured of this problem by removing the cause of the interference. If, however, the destructive behavior becomes a habit, there is little hope for a remedy. From your description, it sounds like this is now a chronic habit.

There is, however, one small glimmer of hope. This exists only because your male seems to enjoy drinking the egg fluids. Filling eggs with a horrible-tasting surprise is seldom effective, because in the vast majority of cases the offending bird’s intent is to break the eggs, not eat them. As already mentioned, this egg destruction occurs because of misplaced aggression caused by resentment of some type of activity, or object, within view of their area, or because of an abnormal decision by the male that the eggs represent an intrusion of strange objects into the nesting site. In either case, anxiety and feelings of insecurity motivate this problem.

In your situation, it appears that the male is continuing his destruction because he receives what he considers a gastronomic delight. If this assumption is true, then there is hope for your mustard egg solution to the problem. It will definitely take more than one mustard egg to make a lasting impression, though.

You must be ready with these surprises so that you can switch eggs when the hen begins to lay her next clutch. Pull her eggs as she lays them, and replace them with his foul-tasting surprise. Prepare to continue to replace broken mustard eggs with more of the same until your male learns his lesson. If it works, he should eventually let the female begin to sit on the “clutch” of mustard eggs. When she has been able to sit for a full week, it probably will be safe to take her original eggs out of the incubator and make the final switch. If this does not work, you must resign yourself to pulling all of her eggs for artificial incubation as she lays them.

Using powdered milk in the water as a calcium supplement is a definite no-no. Above and beyond the bacterial problems that can occur, even with the frequent water changes, there is the lactose-intolerance factor that birds share with many human adults. Although milk supplements have historically been used with success in hand-feeding formulas, there are enough alternative ways to supply calcium to adult birds to make milk unnecessary. In fact, if your birds make full use of the calcium additives you already offer, there should be no need for further supplements.