How have captive-breeding programs helped restore populations of endangered birds?

Captive breeding programs help in two main ways: First it allows breeders to maximize genetic diversity in the endangered population, and secondly allows for multiple clutches (more offspring) than would happen in the wild.

About 25 years ago I had the honor of working with Dr. Kurt Benirschke in San Diego as a volunteer (for about a year). The staff under his direction had worked out a technique to determine the gender of birds (some are monomorphic) and were using it to help reestablish the California Condor. (see http://www.answers.com/california+condor%29. Another project was to monitor urine samples to determine optimal times for breeding. They were in a race against time to build up the numbers of endangered species.