Dear Rafael,

Please check these useful PDF attachments.

Good Luck

Rafael -

Nice question.  This is not an area of expertise for me, but as a retired statistician, I am wary of the way statistics are kept and interpreted, and like to be certain that this is considered. The attachments which Arvind supplied were very interesting with regard to your project, but we cannot take numbers at 'face value' without knowing how they were collected and understanding what they mean.  The second of his two attachments, at a glance, noted "background rates" of extinction, which apparently help you interpret the other numbers, so that seems like something important to understand.  I would also like to emphasize the importance of studying bias and variance for these estimates, and their exact meaning and data collection methodologies.  If such metadata were not discussed, they should be.

What occurred to me when I read your question is that when you look at a percent, such as extinctions from one cause as a part of all extinctions, you do have to have a good estimate, not only for extinctions due to that cause (hunting here), the numerator in your fraction, but also a good estimate of all extinctions, the denominator in your fraction of interest. 

It is my understanding, or at least I've heard, that many species of plants, or maybe just bacteria or fungi, likely come into existence and later become extinct, without our ever even knowing about it.  But you may just be talking about animal species, which I would guess would be less likely to have such a problem on a large scale, though I would not know.  My point, however, is that if you mean you are looking at extinctions from one cause as opposed to all others for animals, or say, for animals in Cuba, you should say so.  It is important to define exactly what you are trying to count, and to discuss the factors which may impact the meaning and the accuracy and precision of your results. 

Best wishes with your project. 

Cheers - Jim

PS -  Among your obstacles is to know what species were present within your area of interest (scope) 500 years ago, and what actually did cause extinction.  There could be multiple factors to which extinction may be attributed. How will you count them?  Might you strive for an estimated percent where hunting was likely the major cause, and another estimated percent of cases where hunting was likely a contributing cause, for example? 

Ectopistes migratorius (Halliday, 1980)

Halliday, T.R. 1980. The extinction of the passenger pigeon ectopistes migratorius and its relevance to contemporary conservation. Biological Conservation, 17: 157-162.  

Raphus cucullatus (BirdLife International).

http://www.birdlife.org/datazone/speciesfactsheet.php?id=2441

Pinguinus impennis (BirdLife International).

http://www.birdlife.org/datazone/species/factsheet/22694856

Thinking about it, I do not see any way you could obtain traditional estimates of accuracy and precision (bias and variance), but there are other metadata you could report.  You could note your resources/references, methodology, and any discrepancies found, and report a reasonable range of results that could accordingly occur.  (References should always be given, but I mean you could especially note the data used.) 

By the way, you might find the following to be of somewhat related interest:

 https://www.ncsu.edu/labwrite/Experimental%20Design/accuracyprecision.htm

Hi, Rafael,

you mean completely extinct, or extinct in some area, like country, geographical realm (e.g. Cheetah in America) or some part of biogeographical region? Total amount of some extinct taxonomic groups is known. I cited in my Nature Conservation 2002, the Book of  Yablokov A.V., Ostroumov S.A. Levels of Living Nature Conservation. Nauka Press, Moscow. 1985. 176 p.

it is in Russian, somewhat old but still actual. Look page 85-86 where is the table...

Also exist a lot of special literature about large predators or ungulates, like

Anton & Turner - The Big Cats and Their Fossil Relatives - I have it in Russian translation!

The problem is that no so much serious monographs. But articles - a lot of (look, e.g., about Rhinoceros sondaicus subspecies). Moreover with java Rhino it goes badly as indonesians are making SAFARI in Ujung Kulon, that I know exactly from local rangers (permission for Rhino - 2 th. USD). if kill do not know how much...

Moreover, what does it mean hunting - with a gun, arrow, peaks etc. ? And what  about net, angling, spining, harpun, and overgathering ? Exist a lot of species, that are not suffer only from hunting, but of several threats, and hunting is the only one factor!

So, if you or smbdy other will wright  the book about - will be scientific exploit...

And thanks for  the perfect question,

Andrey

I cannot think of a large vertebrate (>1kg) extinction in the last 500 years that was NOT due to hunting. Exceptions, anyone?

Dear Truman, were is a list available.

For this Wikipedia (not the best resource, but a good start): https://en.wikipedia.org/wiki/List_of_extinct_animals_of_Europe

and links to other continents at the bottom of this article.

Two papers about the extinction of a bird (Podiceps andinus) and a seal (Monachus tropicalis) in South America

Hi Claudia, thank you for the pdfs

Rafael -

I think I misunderstood your question in a way that made it much harder, even, than it is.  

If you want to know the percent of species made extinct primarily by hunting, and the percent of species made extinct in other ways, then you need to know the percent of all species that were made extinct.  So if A is the number of species made extinct by hunting, B is the number of other extinct species, and Z is the number of all species, then assuming no new species,

(A/Z)(100%), and

(B/Z)(100%), 

could both be very small percents.    Even if Z is really only just for vertibrates, or whatever subcategory of all species you are really examining, with A and B both counts for subsets of the vertibrates, the percent of such number of species made extinct by any means might still be small. 

But I realize now that you may just be looking at the number of species made extinct, without worrying about how many species (of vertibrates or whatever your overall population) there are altogether, and asking that, given a species was made extinct (in statistics this is called a conditional probability), what percent of those were made extinct primarily by hunting?  This is a much easier question - though still very hard, but at least more reasonable.  Sorry. 

First, you are probably not talking about all species on earth, so a new species of bacteria is probably not of interest.  Second, even among the group of interest, say perhaps vertibrates, you are only looking for extinct species and their causes.  Now redefining A as the number of extinct vertibrate species made so by hunting, and B as the number of those made so by other means, then the percents you may be looking at would be

[A/(A+B)](100%) and

[B/(A+B)](100%). 

That would be first the percent of the number of extinct species of interest that were made so primarily by hunting, and second, the percent that were primarily made extinct by other causes, and those two conditional percents add to 100%.  So now, with regard to precision and accuracy, you just want to know How closely to the truth might you estimate the numbers A and B? 

As noted by Truman then, it might be fairly accurate, depending on the overall category, say perhaps it is only a subset of vertebrates, say you are only interested in big cats, or only large flightless birds, to say that for such an overall group, the percent made extinct by hunting is 100 percent.  In that case, the number B, say the number of large flightless birds made extinct by phenomena other than hunting, may be zero. 

The bad news is that even if (A/(A+B)) < 1 in the future, it may be because of climate change, which is no better than hunting as a human failing of animal care. 

Cheers - Jim

PS - Sorry I think I assumed incorrectly about your goals.  I reread your question after I read Truman's answers.  Hopefully, however, this exercise illustrates various considerations of importance.  

Dear James i am taking note of your all comment, thank you. I am considering with more emphasis in vertebrates because are the species more affected by hunting. But I could include a gereral considertion later.

Good question Rafael, though very difficult to answer. 

Surely two cases are emblematic: the Dodo and the Passenger pigeon, hunted to the last one.

The great auk is another example (flighless seabird in northern Atlantic). There is lots of literature - they even know the names of the guys who killed the last individuals in Norway and Iceland.

However, I think that overall there are relatively few examples of cases that went to extinction. In contrast, there are many examples of where hunters have taken steps to save the last individuals and began restoration - many decades before conservation was invented as a discpline - examples like Alpine ibex in Europe, deer and turkeys in US etc etc.

I fact, Dodo was not only extinct by hunting but also for introducing the enemies (which is maybe more important in its case); and Passanger pigeon is clear example by extinction of hunting.

There are also couple of species which was at the edge of extinction: Saiga Saiga tatarica and Bison bonasus - both restored by human being.

other animals extinct from hunting: Hydrodamalis gigas; Congoni - Alcelaphus buselaphus buselaphus (subspecies); Javan tiger - Panthera tigris sondaica (subspecies); Zanzibar leopard - Panthera pardus adersi (subspecies); Capra pyrenaica pyrenaica (subspecies) - Pyrenean Ibex (John Linnell - do you meant this one?); Western African Rhyno - D. bicornis lohgipes (recently extinct - officially on 2011) and other subspecies will extinct very soon as well; Tasmanian wolf; etc...

To add of some birds:

Hawaian Honeysuckers (Moho nobilis, etc) - completely extinct group of several species;

New Zealand starlings - Guyas (Heteralocha acutirostris); Ara tricolor -  Cuban Macaw extinct not only by hunting but also deforestation etc.; New Zealand owl Sceloglaux albifacies - also same fate as Dodo extinction made by cats, rats and other human co-habitants brough to Island; Psephotus pulcherrimus - Australian parrot extinct by collecting eggs for consumation and help of human co-habitants; Numenius borealis, Gallirallus wakensis - was killed and eaten by human being; Parrot (the only native to North Americas Conuropsis carolinensis was simply killed, even not for food.

ETC....

A lot depends on what you mean by "hunting". Are you talking about poorly regulated or unregulated but legal harvest (which drove the historic cases I mentioned like Great auk, passenger pigeon) - or the illegal use of wildlife which is associated with bushmeat or the general wildlife trade - like rhino horn, ivory etc). These are two very different issues and most hunters (in a European or North American context) would clearly distance themselves from poachers. In other words - all human killing of wildlife is not hunting. Some killing can be regulated and sustainable and legal (= hunting) - the rest is illegal killing or poaching.

John, it doesn't matter which way it is done - the rezult is only important from the side of the extinct animals, believe me. And for the sence of the question.

At least, I'm not actually like to discuss here stuff like legal hunting - poaching, trophy hunting etc.

Hello everyone,

It was a great deal information that you  have shared. It would be further useful if some could add some very important reference paper in this aspect

Have a good day