400 



POPULATIONS 



The herd in the Bialowies Forest in 

 Lithuania contained almost 1900 animals 

 in 1857; by 1892 the number had been re- 

 duced to 375, with 101 more hving in a 

 neighboring forest. The main herd was the 

 property of the imperial family of Russia 

 and was adequately protected from poach- 

 ing except during wars. Harper (p. 533) 

 cites statements showing that the depreda- 

 tions of formerly formidable enemies such 

 as bears, wolves, and lynxes were brought 

 under approximate control. The herd suf- 

 fered from diseases, from hver flukes, and 

 from "continuous in-and-in breeding, the 

 slowness of breeding or infertihty of the 

 cows, and the [relatively] large percentage 

 of bulls." 



In 1913, shortly before the First World 

 War, there were some 750 wisents in the 

 Bialowies herd, but these were killed ofif by 

 poachers and disbanded soldiers. After the 

 war, the new PoHsh state purchased five 

 wisents elsewhere and installed them 

 within the forest in a corral with an area 

 of 240 acres. There was some shght in- 

 crease up to nine pure-blooded stock and 

 five more wisent-bison hybrids. A herd in 

 Pohsh Upper Silesia contained nine ani- 

 mals that were wholly wisent and quite 

 wild. 



"In March, 1935, an exchange of wisent was 

 arranged between Poland and Sweden. . . . 

 Poland gave two Caucasus stock heifers . . . 

 to the wisent herd near Stockholm and received 

 in exchange a 22-year-old cow and a 5-year- 

 old bull. These two, together with two cows 

 that had been living in Bialowies [for 5 and 6 

 years, respectively] are the only ones of pure 

 Bialowies breed remaining ..." (Harper, p. 

 534). 



Elsewhere, the interbreeding with intro- 

 duced American bison was so conducted 

 that bison cows were mated with wisent 

 bulls; resulting bull calves were excluded 

 from breeding and the hybrid heifers were 

 bred back generation after generation to 

 wisent bulls. "At the end of 10 generations 

 the descendents can scarcely be distin- 

 guished from pure stock wisents. ..." 



In 1930, although Caucasian bisons were 

 not known to be ahve. Harper says (p. 

 537), "there was a trustworthy report of 

 a few survivors in one of the least acces- 

 sible parts of the Kuban district" and that 

 the Russian government had established a 

 reserve of over three-quarters of a million 



acres in a locahty formerly occupied by 

 the European bison, of which, however, 

 the keepers had not found any recent trace 

 by 1931. 



It is hard to ascertain the effect of 

 World War II on the reduced, scattered 

 stock of wisent even though no feral ani- 

 mals are now known. In June, 1947, the 

 Duke of Bedford's herd at Woburn Abbey 

 in England contained twenty-one Euro- 

 pean bison.** The herd contained three 

 calves of the year, of which one was a 

 female. In addition to four bulls and ma- 

 ture cows, there are also four other females 

 three years or less in age. The wisent on 

 the European continent numbered ninety 

 as nearly as could be discovered under the 

 difficult conditions obtaining in December, 

 1946.t Their distribution was reported as 

 follows: 



Poland and Russia 42 



Sweden 14 



Holland 4 



Switzerland I 



Germany (Springe) 14 



(Munich) 15 



Total 90 



These ninety wisents, presumably pure- 

 bred, are to be compared with the seventy 

 three estimated by Mohr (1933) as forming 

 the European total of such animals for 

 1932. Harper's concluding statement in 

 1945 (p. 536) summarizes the situation 

 with an accurate understatement: "Efforts 

 to obtain the best breeding results from 

 this small and scattered stock appear to 

 have been hampered somewhat by interna- 

 tional rivalries." 



A considerable amount of information is 

 available about minimum populations in 

 insects. Often the last individuals in a local 

 population need not be destroyed to eradi- 

 cate an insect pest from a given locahty. 

 After the pest population is sufficiently re- 

 duced in numbers, the remainder die off 

 from natural causes, and the species does 



** Personal communication from the Duke of 

 Bedford. 



t Personal communication from Miss Edyth 

 H. Franz, Assistant Secretary, American Com- 

 mittee on International Wild Life Protection, 

 based in part on a similar report by Miss Erna 

 Mohr, Recorder of the studbook on wisent 



populations for the Society for the Preservation 

 ot the Wisent. 



