I don't doubt that the lady "thought" she saw an ostrich. It was an ostrich to her, but that don't mean it actually was an ostrich.
As an aside, lets say 10 people are looking at a guy walking down the street. A car pulls up a man gets out and shoots the guy walking down the street and exits. Ask the 10 witness's what color was the car? Ask them what color was the shooter for that matter. You will get a lot of different answers. If you ask if the shooter was a woman, some will say yes. If you ask them if the car was red, many will say it was.