California Department of Fish and Wildlife

Reintroductions

Sierra Nevada Bighorn Sheep Recovery Program

Video describing March 2014 reintroduction effort (click to open full size Youtube window)
 

Video describing March 2013 reintroduction effort (click to open full size Youtube window)
 

Helicopter ferrying captured bighorn sheep

Helicopter ferrying in Sierra bighorn (photo courtesy Lucas Barth)
   

Taking samples of bighorn sheep while at base camp during capture March 2013

Sierra bighorn at processing site during translocation (photo courtesy Lucas Barth)
 

Sierra bighorn ewe leaving release site with collars visible

Released ewe heads off towards Olancha Peak (photo courtesy Lucas Barth)
 

Cathedral Range - in progress

On March 26, 2015, this herd unit became occupied in the heart of Yosemite National Park. Initially, Eight pregnant ewes and one non-pregnant ewe were released. Three days later, on March 29, 3 rams were released and on April 3 a final pregnant ewe was released, bringing the total population up to 13 animals. Each bighorn was fitted with a satellite GPS collar allowing daily monitoring of their movements and health for the first two years. While the oldest ram died immediately following release, the rest of the population is faring well and adjusting to their new home. Early GPS data shows exploratory movements in their expected range. Most lambing normally occurs in May-June timeframe so newly born lambs should join the herd not long after translocation. Three lambs newly born have been observed so far.

Olancha Peak - in progress

March 25, 2013 marked the first translocation to create a new Sierra Nevada bighorn sheep herd since 1986 when the Mono Basin herds at Mt. Warren and Mt. Gibbs were first repopulated. Ten pregnant ewes and four rams were released on March 25-26. Each was fitted with a satellite GPS collar allowing daily monitoring of their movements and health for the first 30 months. During the first year of observation, all animals seemed to adapt well to their new home. Lambing season, May-July, resulted in eight documented lambs. One ewe apparently lost her lamb shortly after birth and one ewe was not observed with a lamb. In May 2013, one ram returned home about 25 miles north to the Mt. Langley herd unit, leaving three rams remaining. On March 22, 2014, this herd was augmented with four additional ewes. On March 29, 2015, two additional rams were released to help increase genetic diversity in this herd.

Big Arroyo - in progress

Big Arroyo is located in the Great Western Divide and is part of the Kern River recovery unit. On March 19, 2014, this herd unit became occupied for the first time since early in the twentieth century. Ten pregnant ewes and one ram were initially released. On March 22, an additional three rams were released. Each is fitted with a satellite GPS collar allowing daily monitoring of their movements and health for the first 40 months after release. Similar to the strategy at Olancha Peak, additional bighorn releases are planned for this population within two years to augment the original herd.

Since this area is geographically isolated from the main body of the Sierra Nevada, this herd serves as an important reservoir of bighorn separate from the east side populations. Creating a herd in the Great Western Divide area has some additional logistical challenges not common to most other herd units. Monitoring of these populations will require significant effort in with more than 25 miles of backcountry travel to get there.

Laurel Creek - in progress

Laurel Creek, similar to Big Arroyo is located in the Great Western Divide and is part of the Kern River recovery unit. On March 30, 2015, this herd unit became occupied for the first time since early in the twentieth century. Seven pregnant ewes and four rams were released. On Each is fitted with a satellite GPS collar allowing daily monitoring of their movements and health for the first 40 months after release. Similar to the strategy at Big Arroyo and Olancha Peak, additional bighorn releases are planned for this population within two years to augment the original herd.

Since this area is geographically isolated from the main body of the Sierra Nevada, this herd serves as an important reservoir of bighorn separate from the east side populations. Creating a herd in the Great Western Divide area has some additional logistical challenges not common to most other herd units. Monitoring of these populations will require significant effort in with more than 25 miles of backcountry travel to get there.

Taboose Creek - colonization in progress

This herd unit, adjacent to Sawmill Canyon and just south of Coyote Flat, is showing signs of incipient colonization. Since 2012 our field crews have repeatedly observed rams within the herd unit boundaries. Some ewes have been observed, but no lambs to date, so it is unclear whether a breeding population exists yet. Depending on how the potential colonization proceeds, bighorn may or may not need to be reintroduced through human assistance. As the other reintroductions proceed, we will continue to monitor and explore this herd will continue to be monitored and explored to determine the best course of action.

Augmentations

Mt. Warren

This herd was augmented with six preganant ewes moved to Lundy Canyon in 2009. Three ewes were moved from Wheeler Ridge and three ewes came from Mt. Langley. All six of the ewes survived at least two years and produced lambs. During the next three years, three perished. One died of unknown causes during a harsh winter, one fell down a small cliff and one was killed by a mountain lion. Two rams were moved to Mt. Warren in 2003. The following year one was hit by a car on Conway Summit and perished. The other survived for nine more years likely producing offspring with different genetic stock. This herd will be augmented again in the next one to two years to expand their geographic range south to include Mt. Scowden and Mt. Warren, while diversifying the base genetic stock.

Mt. Gibbs

This herd was augmented with three ewes, two of which were pregnant, from the Mt. Langley herd in 2013. Genetic analysis indicates low genetic diversity in this herd. The newly-arrived ewes were selected for high genetic diversity to help increase the genetic diversity of the herd in an attempt to raise the low reproductive rates observed in past. On April 3, 2015, we added an additional 5 pregnant ewes with the intention of creating a new deme or subpopulation just south of the current population in the Algers Creek area. These ewes, with known genetics, were specifically selected to increase the genetic diversity of this herd.

Convict Creek

This herd was augmented with three pregnant ewes from the Mt. Langley herd in 2013. This very small population should benefit by increasing the number of ewes to complement and assist the natural colonization of this herd. The translocated ewes were selected for high genetic diversity to help ensure that the genetic stock remains diverse. Having collared animals in this newly colonized area will also help to define habitat usage patterns and assist in comprehensive population surveys.

Mt. Baxter

Five pregnant ewes were moved to Mt. Baxter from the Wheeler herd in 2005. Later that year three of the translocated ewes moved north to Sawmill Canyon. One of the remaining ewes moved south to Mt. Williamson in 2007. All five ewes survived to lamb for at least two years. Four of the relocated ewes were killed by mountain lions between 2007 and 2009. The remaining ewe survived and reproduced at Mt. Baxter for many years. This herd is currently large enough to be a source for translocation stock rather than requiring additional augmentation.

Mt. Langley

Mt. Langley was augmented with a single ram from the Wheeler Ridge herd in 2001. He was released further north, in the Mt. Williamson area, but moved south over a period of several months and became a permanent resident of the Mt. Langley herd for at least six years. This herd is currently large enough to be a source for translocation stock rather than requiring additional augmentation.




Many endangered species remain on the brink of extinction with poor prospects for recovery after they receive federal protection. Through our conservation efforts, we have a unique opportunity to reach recovery goals for an alpine specialist that is native only to California.


------------------ Program Manager Tom Stephenson ------------------