Elk are relatively recent immigrants to North America, at least in geological terms. Elk migrated to North America over the Bering Land Bridge approximately 120,000 years ago under a period when much of the world's water was locked in glaciers.
Archaeological evidence suggests that elk inhabited these areas over the past 10,000 years; however, they were gone from the area by the mid-1850s, based on discussions and writings of Native Americans, early explorers and settlers. Following their extirpation from Washington, the area was devoid of elk for several decades until the 1930s, when Rocky Mountain elk were brought from Yellowstone National Park in Wyoming and reintroduced to Washington in the Cascade Mountains near Mt. Rainier. Elk were first seen on the Monument in 1972. This original group of animals was believed to originate from the Cascade Mountains to the west and arrived naturally. Since approximately 1975, the Rattlesnake Hills Elk Herd core range has been the Arid Lands Ecology Area on the Monument and private land to the south and west. Peripheral rangelands include the Hanford Site, the Rattlesnake Hills west of State Route 241, the Yakima Training Center, and southern Grant and western Franklin Counties.
There were six subspecies of elk in North America (two are extinct). Rocky Mountain elk are native to the Columbia Basin and the Hanford Reach National Monument; the elk on the Monument are Rocky Mountain elk.
Prior to the 1800s, elk lived in every state and province except Alaska and Florida. Today, their range has been reduced to 24 states and seven provinces. Approximately one million elk live in North America today—10% of the population before European settlement. Washington has the sixth largest state elk population, with approximately 60,000 elk (Rocky Mountain and Roosevelt elk).
Elk are amazingly adaptable and can live almost anywhere—forests, deserts, mountains, and plains. They eat a wide variety of plants. Their typical diet consists of grasses (year-round), woody plants (winter) and forbs (summer).
Elk are majestic animals. Cows typically weigh no more than 500 pounds, but bulls can reach 700 pounds and stand 5 feet at the shoulder. Only bull (male) elk grow antlers. Grown annually to display dominance for breeding, a pair of antlers can weigh up to 40 pounds.
Elk mate in autumn. Calves are born 8-1/2 months later, from mid-May through early June, depending on location. Newborn calves weigh 35 pounds, and although newborn calves can walk with their mothers within a couple of days of birth, they usually stay hidden for the first couple of weeks of life. Newborn calves have almost no scent to avoid attracting predators as they lay hidden in thick brush or tall grass; white spots help to camouflage the calf by breaking up its outline and mimicking spots of light.
Rarely seen in the summer when they “head to the hills,” in the winter elk are frequently seen from Highway 240. If you're lucky, you might see these majestic animals from your car. But please be careful if you stop to view them as there is only one designated pull-out along the highway, and traffic can be quite heavy when the shift ends on the Hanford Nuclear Reservation.
Want more information on the Rattlesnake Hills Elk Herd? Read on.
The elk herd that uses the Monument is transient, using the Monument, central Hanford, Wahluke Slope, Yakima Training Center, and other adjacent lands lands. This constant movement of elk means that the size of the herd on the Arid Lands Ecology Area (the primary area used on the Monument) fluctuates considerably by season. In the spring and summer, approximately 150 elk are typically observed on the ALE. During the fall breeding season and with the start of Washington State hunting seasons, herd numbers range from 350-375 animals. During the winter, elk numbers can reach to over 700 animals.
According to the 2011 survey that the U.S. Fish and Wildlife Service and Washington Department of Wild and Wildlife conducts:
Historically, the Rattlesnake Hills Elk Herd has had a high reproductive rate, averaging an approximate 25% initial annual increase. This reproductive output, coupled with low annual harvest, led to substantial population growth throughout the 1980s and 1990s; by 1998, the population was estimated at more than 800 animals. The increasing herd size prompted multiple concerns, including damage to private agricultural lands, potential damage to fragile resources on the Monument, vehicle collisions and public safety on State Route 240, and increased elk presence within Hanford Site surface contamination areas. Efforts to reduce the herd have had some success. Since 1986, hunting seasons on private lands around the ALE have actively harvested elk. The WDFW has continued to liberalize hunting seasons on adjacent lands in order to reduce the herd and alleviate some of the above concerns. Further, the FWS, along with the WDFW and DOE, have conducted two capture and relocation efforts to reduce the herd. In 2000, 191 animals (primarily cows) were removed and taken to the Blue Mountains in Asotin County and the Selkirk Mountains in Pend Oreille County. In 2002, a smaller capture/relocation removed thirty-two animals to the Spokane Indian Reservation. Both increased hunting success and the capture/relocation efforts, combined with reduced calving rates in recent years, have contributed to the reduction in the elk population from its historic high.
The FWS and Washington Department of Fish and Wildlife have been cooperatively monitoring the Rattlesnake Hills Elk Herd population on the ALE since 2001. Standardized winter inventories conducted over the last three years have estimated the herd to be 674 (2005), 537 (2006), 681 (2007), and 639 (2008) animals—a four-year average of 633 elk. The 2008 survey showed a 56:67 sex ratio of bulls to cows. Calf recruitment typically adds about ninety animals/year, and annual harvest on lands adjacent to the ALE is between fifty-seventy animals, although this past hunting season likely resulted in over 100 animals being harvested. Additional animals are likely removed by natural or other causes (e.g., killed by vehicles). As the WDFW’s current population level goal (post-harvest) for the Rattlesnake Hills Elk Herd is 350 animals (WDFW 2002), the herd is still above the targeted level for management.
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Once a national wildlife refuge itself, Saddle Mountain National Wildlife Refuge still exists, but as part of the much larger Hanford Reach National Monument.