Q: This summer, a pair of bare-eyed cockatoos bred for us for the first time and raised a single chick. We pulled the chick at 3 1/2 weeks for handfeeding. The parents are in excellent feather. The chick had good feathering only on the head, wings and tail. On the rest of the bird were strange-looking pin feathers. The shafts were hollow without any blood in them, and there was a black blob on the end of each shaft. Some of the more developed feathers” were the same, and they would fall out of the follicles when the bird was stroked. The baby was tested for polyomavirus and beak and feather. Both tests came back negative. After some time, the strange feathers grew out and were replaced by 100 percent normal and healthy-looking feathers. What do you think happened to this chick?

A: The problem that you describe is encountered at some time or other by most aviculturists who have large aviaries and do not pull the babies until after 3 weeks of age. It is caused by one or both of the parents. What you see is the result of what I will call “abusive preening.” It is a nesting behavioral problem that is somewhere between proper preening and outright plucking. Those who pull babies at an earlier age never see this problem. This is because the babies do not have enough feathering to allow it to happen.

The black blob that you describe on the pin feather is dried blood. Parents that do this will usually do it to all the babies in the clutch. These babies, if allowed to remain in the nest until fledging, would fly out of the nest with naked bodies. They would have only their head, flight and tail feathers. It is interesting to note that this behavior is never commenced until the pin feathers on the body begin to show. By that time, the head, flight and tail feathers no longer appear as pins, even though they still have a blood shaft at their base. These, as well, are the feathers that are most important for survival. We have, to date, seen or heard of this behavioral problem in macaws, cockatoos and conures. It probably also exists in other types of parrots. What triggers this behavior at that specific point in time is unknown. If I had to take a wild guess, I would say that the pins that appear on the baby’s back and wings (with the exception of the flight feathers) appear different to the parents than the pins on the rest of the body. At the developmental stage that the baby begins to require a lot of preening, these pins appear short and fat, rather than long and slender. The “enjoyment” of popping the blood out of these short, fat and juicy pins might “hook” them into this obsessive behavior.