I don't understand. The article states:

It is estimated that there are only 250–1000 mature individuals left, but the bird’s elusiveness puts even those figures into question.

But then the researchers claim that:

Paul Sweet, collection manager for the museum’s Department of Ornithology, told Audubon that he and his colleagues assessed the state of the bird’s population and habitat, and concluded it was substantial and healthy enough to withstand the loss.

So which is it? Do we have only the roughest estimate of the population, or do we know the population is stable enough to take a loss. I don't see how both can be correct...