Science Sunday: Hareless in Wyoming
Sunday, February 24, 2008 at 7:00 am
Jackrabbits vanish without a trace from America’s premier national park.If you put together a list of the wildlife you’d hope to spot on a trip to Yellowstone National Park, it probably wouldn’t include the humble jackrabbit. Good thing, too, because they’ve vanished.
This surprising news was provided by Wildlife Conservation Society biologist Joel Berger in an article in the journal Oryx. According to data collected as far back as 130 years sgo, jackrabbits were once locally abundant. But the WCS found that no jackrabbits have been sighted in Yellowstone since 1991, and there are only three confirmed sighting in Grand Teton National Park since 1978.
There is no clear reason for the rabbits’ disappearance. Berger said:
“It could be disease, extreme weather, predation or other factors … Lacking a sense of historical conditions, it will always be difficult to decide whether current systems function ecologically like past ones.”
Jackrabbits and other lagomorphs are an important food source for some predators, especially coyotes. Studies in the Curlew Valley of northwestern Utah and southern Idaho over several decades have shown coyote population fluctuating in sync with jackrabbit populations.
And in a study of coyote prey in southern Texas, researchers found that about 40 percent of the animals eaten by coyotes over a seven-year period in the 1980s were lagomorphs – mostly jackrabbits. Conversely, deer constituted less than 10 percent of the coyote’s prey over the same period.
Now a coyote will eat almost anything. In a study of Yellowstone coyotes in 1937-38, the legendary biologist Adolph Murie recorded the following among “miscellaneous food and non-food items” in 5,086 coyote droppings: