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Occasional posts - from the quirky to the momentous - on the life and times of the Methow Conservancy.
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Friday, January 31, 2014

Bighorn Sheep of the Okanogan - Video & Notes from the Jan 2014 "First Tuesday"

Jeff Heinlen, WA Dept. of Fish and Wildlife Biologist, gave our January 2014 "First Tuesday" program.  Here is a video of the talk and some notes.  He talked about the cultural history, ecology and life history, and management issues associated with the Bighorn Sheep of Okanogan County.

The video starts about 10 minutes into his presentation and lasts 51 minutes.

Notes by volunteer Bob Herbert
The Methow Conservancy’s first First Tuesday lecture for the 2014 season was presented by Jeff Heinlen.  Jeff spoke to a packed Twisp River Pub crowd about the Bighorn Sheep of Okanogan County.  There are seven herds of Bighorn sheep currently located in and around Okanogan County.  Washington’s herds are divided between two species, the California Big Horn, and Rocky Mountain Big Horn sheep.  Females can grow to around 150 pounds and males can weigh up to 200 pounds, and they choose to live amongst the steepest cliffs they can find. 

Their habitat is their best protection, and their soft, split hooves provide them with the stability necessary to traverse narrow ledges.  Their hoof design is similar to the Mountain Goats of the North Cascades and Rocky Mountains, and they both escape predators by climbing out onto ledges that no other creature dare walk.  Unlike deer and elk, Big Horn sheep’s split hooves are spongy.  This allows them to grip the uneven surfaces of the rock ledges they are climbing.  Their soft hooves can be used to grip and pull themselves straight up vertical cliffs with strength of their front legs.  Their leg bones and joints are also designed with shock absorbers so they can withstand the impact of a twenty foot leap onto solid rock. 

Bighorn sheep are grass eating vegetarians, like deer and elk, but unlike deer and elk, who have antlers that are shed annually, bighorns have horns that they keep their whole lives.  The full shape of their curled horns takes seven to eight years to form and the rings on the horn are one of the ways in which to identify their age.  Their horns make up between 8-12% of their total weight and they are used for protection, as well as for sparring during the fall rut.  In the fall, the males will ram their heads together in order to determine the pecking order for mating purposes.  The rings on their horns represent a years worth of growth, just like the rings on a tree.  The first five years shows the fastest growth and the largest distance between rings.  As they get older, the rings grow closer and closer to one another.  Another way to determine the age of a sheep is to slice one of their teeth.  A cross-section of one of their molars reveals a ring for each year of growth. 

There were seven sub species of Bighorn sheep in the west, but one of them has gone extinct.  By 1935 the entire population of Bighorn sheep was either hunted to extinction (locally), or killed from disease brought over by domestic European sheep.  In 1957, eighteen Bighorn sheep were reintroduced from British Columbia into northern Washington State and they were allowed to reproduce and expand inside of protected pens during the 1960’s.  After they were released near the Canadian border, they spread out south and east over the Columbia basin, until they eventually established seven individual herds.  There are approximately 500-600 Bighorn Sheep currently living in and around Okanogan County, and we are lucky to live amongst these unique creatures!