Each year in May, biologists count rabbits along a standard
31-mile survey route on the INL. Since the survey is conducted at
night, the biologists use spotlights to see the rabbits.
Rabbits have been counted in this manner along this route since
1980. In the early 1980s, jackrabbit populations in southeastern
Idaho exploded and greatly exceeded the level that the land could
sustain. As a result, many rabbits congregated on agricultural
lands, including lands adjacent to the INL, where they became a
significant and costly nuisance for landowners.
Since the INL is representative of much of the upper Snake River
Plain, contains large areas of rabbit habitat, and is an area of
minimal human disturbance, results of long-term surveys on this
site serve as a good means to determine the relative abundance of
rabbits in southeastern Idaho in general. The data gathered here
can be used to provide warnings to area farmers in order to
control losses should numbers approach those experienced in the
early 1980s. Although researchers search for all types of rabbits
during the count, most of the rabbits seen are black-tailed
jackrabbits. Rabbit populations generally follow a cyclic pattern
of high and low population numbers. According to survey data,
jackrabbit populations on the INL appear to peak every 10 or 11
years. During a population peak in 1981, 1194 rabbits were counted
during the 5-hour survey. A much smaller peak occurred in
1992 when 53 rabbits were counted. Another small peak occurred in
2000 when 26 rabbits were counted. In 2007 142 rabbits were
counted: 139 black-tailed jackrabbits, two white-tailed
jackrabbits, and one
cottontail.
