Ratz, one of seven part-timers employed by the aquarium, did her PhD on yellow-eyed penguins. When I told her that I had visited a few of the colonies and been impressed by the conservation effort being put into the birds, she gave a snort and asked me if anyone has told me that the numbers now are the same as when they were first studied in the 1940s. “I bet nobody told you that. There is no evidence that they have ever been common in the past, even a century or two ago.”