From these facts, it seems that the condors require perpendicular cliffs.

In Chile, they haunt, during the greater part of the year, the lower country near the shores of the Pacific, and at night several roost together in one tree; but in the early part of summer they retire to the most inaccessible parts of the inner Cordillera, there to breed in peace.
With respect to their propagation, I was told by the country people in Chile that the condor makes no sort of nest, but in the months of November and December lays two large white eggs on a shelf of bare rock.

It is said that the young condors cannot fly for an entire year; and long after they are able, they continue to roost by night, an hunt by day with their parents.

The old birds generally live in pairs; but among the inland basaltic cliffs of the Santa Cruz I found a spot where scores must usually haunt.

On coming suddenly to the brow of the precipice, it was a grand spectacle to see between twenty and thirty of these great birds start heavily from their resting-place, and wheel away in majestic circles.