Spring is the best time of year to observe snowshoe hares, especially along Refuge roads early in the morning. Usually vigilant, hares appear to temporarily let down their guard during springtime. Some hares are attracted to the early growth - horsetails, grasses and other plants - that sprout in the spring along the edges of roads. Others are interacting socially; it is their breeding season. Hares are less visible during the remainder of the year, although they may still be nearby.
Long-term studies of the fate of radio-collared snowshoe hares in Canada led Karen Hodges, who obtained her Ph.D. studying hares, to state that: "Almost all hares die of predation." Predation begins early in a hare's life. Snowshoe hares - unlike true rabbits - are born fully furred and are active the first day of life. Young hares (called "leverets") are weaned in about ten days and begin to feed on vegetation.
Red squirrels are especially efficient predators on snowshoe leverets; they killed up to 36 percent of the leverets each year during a long-term study (1986-1996) in the Kluane area of the Yukon Territory. Other leveret predators were Arctic ground squirrels, short-tailed weasels (ermine), and small raptors (boreal and hawk owls and Harlan's hawks).
Coyotes, lynx, great-horned owls and goshawks were the main predators of adult hares in the Kluane study, killing over 90 percent of the hares each year. Very few hares survived this constant predation and lived to be four-years old.
Research on the Kenai National Wildlife Refuge has documented the importance of snowshoe hares as prey for the refuge's carnivore community. For example, although moose were the principal food source for wolves and despite a scarcity of hares, 12 percent of 592 wolf scats collected from May to October between 1976 and 1981 by Dr. Rolf Peterson and coworkers contained the remains of snowshoe hares.
Later, during another period of low hare densities (1987-1990), graduate student Win Staples studied diet and habitat relationships between lynx and coyotes on the refuge. When the ground was snow covered, snowshoe hares remains were found in 91.3 percent and 25.7 percent of 161 lynx and 179 coyote scats, respectively. During snow-free months, 66.7 percent and 47.5 percent of the lynx and coyote scats, respectively, contained snowshoe hares remains.
Coyotes were apparently less successful capturing hares in the winter than lynx and relied on other sources of food, such as scavenging from wolf-killed moose carcasses. Such scavenging was however dangerous: wolves killed three of the nine radio-collared coyotes. Win Staples concluded that there was "exploitation competition" for food between lynx and coyotes, because both used the same habitats and because hares, a major food of both predators, were scarce at that time.
With coyotes a relative newcomer to the Kenai Peninsula, arriving here in the early 1900's, there was and continues to be a concern about competition between lynx and coyote for snowshoe hares, especially in regards to the environmental effects of climate warming.
The highly adaptable and successful coyote has expanded its range throughout the United States and has even taken up residence in major cities like Chicago. A coyote was live-captured and removed from Central Park in New York City in February of this year, for example. In contrast, lynx range in the contiguous-48 states has declined and in 2000 lynx were placed on the threatened species list. A recent analysis of lynx reintroduction into their southern range concluded that successful reintroduction requires minimal human disturbance and high densities of snowshoe hares for food.
Lynx with their wide, webbed feet hunt snowshoe hares better than coyotes when winters are long and the snow deep and soft. Coyotes with their narrow feet hunt hares better when there is less snow or when a weight-supporting crust develops on the snow during warm winter weather.
Coyotes may also be more apt than lynx to travel on roads and use snowmobile trails during winters with deep snow. With current levels of snowmobile use, if the trend toward warmer winters with less snow or more crusty snow continues, and more roads are built, the future may eventually favor the ever-adaptive coyote over the deep-snow-dependent and cyclically scarce lynx as the major mammalian predator on the peninsula's snowshoe hares.
Ted Bailey is a retired Kenai National Wildlife Refuge wildlife biologist who has lived on the Kenai Peninsula for over 34 years. He maintains a keen interest in the Kenai Peninsula's wildlife and natural history.
Previous Refuge Notebook articles can be viewed on our website http://kenai.fws.gov/. You can check on local birds or report your bird sighting on the Kenai National Wildlife Refuge Birding Hotline (907) 262-2300. Previous Refuge Notebook articles can be viewed on our website http://kenai.fws.gov/. You can check on local birds or report your bird sighting on the Kenai National Wildlife Refuge Birding Hotline (907) 262-2300.
Peninsula Clarion ©2014. All Rights Reserved.