Dore “Raven”
https://hyperallergic.com/102457/rediscovering-the-dark-splendor-of-gustave-dore-with-edgar-allan-poe/ downloaded Feb 18, 2018
It is the 12 of April 2018. Don’t let the title or lead image mislead you. This is a happier one. It’s a success story. We are not in dire peril from black footed ferrets. Maybe we can learn from them one day.
There was a time when the black footed ferret was extinct in the wild but still thrived in captivity. Measures had been taken that would have assured the survival of these weasels, but there were none left in the wild to protect. So over 4 years, 1991 through 1994 inclusive, captivity bred ferrets were released, a few dozen a year. At first it didn’t seem to be going well. The animals known to be living in the wild did not increase in number so the program was stopped. By 1997 they gave up counting the few stragglers.
Rapid Population Growth of a Critically Endangered Carnivore. M. B. Grenier, D. B. Macdonald and S. W. Buskirk SCIENCE volume 317 10 August 2007 page 779 figure 1. The vertical black bars are the number of black footed ferrets released. The vertical grey bars are the number counted. Years of release or counting are along the horizontal axis.
Then in 2000 they did another count and found that there were still ferrets out there. It had been six years since the last release, and those had done poorly over the years they were counted. And now the growth of the population was very vigorous indeed.
I wasn’t there, and they did not mention it, but I would assume that care was taken to assure a lot of Genetic Diversity among the released animals because that is a Good Thing. I’m sure you understand my sarcasm and hope you can forgive it.
In the early days after the study I watched a program on the collapsing birth rate worldwide. I wrote all of the authors and only one responded. He seemed to think there was no such thing. He new about the black footed ferret experience, so I pointed out that the explosive growth was not seen for some three to six years after the last release; all he could see was “exponential growth.”
At last he gave up on me. Hmm. Exponential growth, eh? Let’s look a little closer. There is a red line that shows a fair exponential growth curve and has been fitted by computer to give a best match. Were growth truly exponential, the line would fit the tops of the grey bars perfectly, give or take noise. But in fact, at the far left, the bars lie below the exponential growth curve, at or above it in the middle and then back to below at the end.
