Some time in the small hours of Wednesday morning, when a small, pale gray chick punched its way through a wall of white calcium, the District of Columbia's bald eagle population shot up by 50 per cent.

It was the first bald eagle birth at the National Zoo in five years. The zoo's two adults, acquired in 1962 from the Calgary Zoo and poetically named 29,181-A (the male) and 29,181-B (the female), had produced a chick in 1973, but then had come a baffling series of misfires and mishaps.

Eggs had disappeared. Was it theft? Eggs had broken. Were pesticides and pollutants robbing them of their resiliency? Eggs had proved infertile Were 29,181-B and -A being distracted or disturbed by the other birds of prey housed with them in their flight cage?

Since 1976, curator of birds Charles Pickett has been removing bald eagle eggs from their nest in the hope that they would fare better in an incubator under human care.

The baby eagle, tentatively named Trateba,' a Mohave word for "beautiful bird," will continue to reside in its incubator for the next three weeks, while the temperature is gradually lowered from 99 degrees to that of the great outdoors. Pickett said he then hopes to lodge the bird in a willing nest at the U.S. Fish and Wildlife Service's Patuxent Wildlife Research Center.

Irateba was given its first meal, of raw chicken, yesterday morning after a 24-hour "drying out" period. "If you tap him on the beak, it'll just open up like a regular bird," said keeper Paul Tomassoni as he demonstrated his feeding technique.

The eagle's sex has yet to be determined.

Zoo officials cautioned that the first 10 days of an eagle's life are a crucial period, but seemed optimistic about this particular eagle's chances of surviving.