Recent aerial surveys of Yellowstone National park have yielded an annual count of bison living in the park in excess of 4230 animals. This represents an increase of nearly 14% over last year’s count. More than half of the bison are in the northern herd. Park Spokesman Al Nash says while this is positive news that the park’s bison herd is healthy and viable,problems from that concentration to the north could arise if the park sees a hard winter. Nash says with population levels like those reported, a severe winter would prompt a number of bison to move toward and over beyond the park’s northern boundary. Then he says all of the interagency bison management plan partners would look at strategies available to address that bison activity. Nash says the observed rate of population change over the past year is within the natural range of expectation. Nash says looking at data over the past several years shows that if there hasn’t been a severe winter that results in a lot of winter kill, or if there hasn’t been a significant exodus of bison out of the park which has then has resulted in some management removals there has been a steady increase in bison in Yellowstone. The peak population estimate of bison in the park was 5,000 recorded in the summer 2005.