Parks Canada Agency – Wood Buffalo National Park


Monitoring of wood bison in Wood Buffalo National Park includes bi-annual segregation counts, along with aerial population estimate surveys, which are conducted at 5 year intrvals.

  1. Segregation Counts – Monitoring population ratios (i.e. calf to cow and yearling to cow) has been conducted in the Park in one form or another since 1974. Calf to cow ratios are used mainly as an index to herd productivity (reproductive success and survival to yearling stage. They may also help determine rate of herd increase; mortality rates; herd age structure and perhaps as an indication of herd health, nutritional level and even range condition.
  2. Population Estimates – Monitoring the bison population began in 1948, but the degree of effort was variable until permanent strip transect survey methods were adopted in 2002.  The arial population surveys help determine  the trend in the size of this population and to some extent, its spatial distribution.


  1. For the segregation count, animals are classified into calves, yearlings, adult (≥ 2 year-old) female, immature males and three classes of adult males. Body size, pelage, horn shape and size are the characters used to separate the animals into categories.
  2. The aerial survey for the population estimate includes what is thought to be the entire range of habitat for this population. The range of how intensely an area is searched is standardized to retain consistency with the results from year to year, but is somewhat dependent on the quality of habitat and visibility. Using GPS and GIS technologies, and from a fixed-wing aircraft, the navigators record bison positions and designate the bison groups as being on transect, off transect, or in a 100% coverage area. Both an estimate and an accompanying estimate of precision can then be calculated.


  1. Typically segregation counts take place in the Peace-Athabasca Delta, because it is less difficult to locate and conduct a ground-based sex/age count of herds on the less forested landscape of the delta than it is elsewhere in the park.
  2. The arial population estimate survey is done systematically and is thought to include the entire ranges of the Delta, Garden River, Hay Camp and Nyarling subpopulations, as well as about half the range of the Little Buffalo subpopulation.


  1. The segregation survey is conducted in mid-late June, as by this time the majority of calving has taken place.
  2. Aerial transect surveys for the population estimate are flown in March, when the animals are easier to see on the lansdcape and there is adequate daylight.

Project Lead:

Rhona Kindopp
Wood Buffalo National Park
Box 750
Fort Smith, NT X0E 0P0

Phone: 867-872-7932
E-mail: rhona.kindopp@pc.gc.ca