Throwback Thursday: Controlled Burns for Improving Wildlife Habitat

By Tom Batter, WIL Scientific Aid

Today we feature an article that looks at how the Department of Fish & Game utilized controlled burns as a management tool.  As the article states, fire has influenced plant and animal species for centuries.  It is a common misconception that many animals are killed by fire.  In fact the primary effect fire has on wildlife is habitat alteration.  Some plant species have actually adapted to cope with fire. This article mentions pyriscence as an example. Pyriscence is when the maturation and release of seeds is fully or partially triggered by smoke and/or fire resulting in new plant crops.

Managing habitat with fire also reduces fire risk by lowering the fuel load.  Large fuel loads -dead plant material and brush build up- that are allowed to accumulate over time cause fires to burn hotter and spread more rapidly.  These are the types of wildfires that are more likely to become dangerous and destructive to people and property.

Using fire as a tool is still an important technique in managing habitat for various species of plants and animals today.  This article originally appeared in the November-December issue of Outdoor California in 1973.





Photo Album of Large Mammal Captures – Spring 2014

This spring the Wildlife Investigations Laboratory assisted with 8 large mammal captures throughout California.  Wildlife capture projects are conducted to help biologists and veterinarians assess the health of these herds through biological sampling,  to place GPS collars on the animals to monitor movement and help study habitat use, and for translocating animals.  A total of 207 animals were captured including 132 deer, 21 pronghorn antelope, 36 elk and 18 bighorn sheep.  Below is a small collection of photos from our month in the field.

Large mammal project locations.  Spring 2014

Large mammal project locations. Spring 2014

Bandaging elk antlers to prevent injury

Bandaging elk antlers to prevent injury

Stabilizing elk for transport to trailer for relocation to another site.

Stabilizing elk for transport to trailer for relocation to another site. San Luis Refuge, US Fish and Wildlife Service, Merced County.

Pronghorn antelope

Pronghorn antelope, Modoc County. Photo by Richard Shinn.

Helicopter bringing deer into basecamp for health monitoring

Helicopter bringing deer into base camp for health monitoring, Inyo County

Translocation and release of Sierra Nevada bighorn to augment herd in Olancha

Translocation and release of Sierra Nevada bighorn to augment herd in Olancha, Inyo County.

Deer release after GPS collaring and health monitoring - Scott Valley, Siskiyou County.

Deer release after GPS collaring and health monitoring – Scott Valley, Siskiyou County. Photo by Eric Haney

Throwback Thursday: On Wildlife Management

By Tom Batter, WIL Scientific Aid

They say you can’t know where you’re going if you don’t know where you came from.  Our latest installment of Throwback Thursday takes a look at an article from the November 1956 issue of Outdoor California discussing what wildlife management is, and why it is needed (and a bonus for any poetry fans out there).

By today’s standards, we would substitute ‘game’ for ‘wildlife’ in the article title as the author, Jack R. Beer, takes a very game-centric approach in his discussion.  Which makes sense considering his job title was ‘Game Manager.’  Regardless, the main points in this article still apply to wildlife management today with the understanding that the principles expand to encompass all wildlife, not just those species which are harvested.


The Tule Elk, A California Comeback Story

By Tom Batter, WIL Scientific Aid

The elk (Cervus canadensis) to this day remains an icon of what once was the unsettled, untamed American frontier.  There are four extant subspecies of elk in North America.  The Manitoban elk (C.c. manitobensis) is exclusive to Canada, but the other three subspecies can be found in California.  They are the Roosevelt elk (C.c. roosevelti) of the north coast rainforests, Rocky Mountain elk (C.c. nelsoni) of the northeastern counties, and the tule elk (C.c. nannodes) native to the Central Valley.

Elk distribution in California.

Elk distribution in California.  Photo courtesy of the DFW Elk Management Program.

Tule elk look similar to other elk in general size, shape, and color (albeit tules wear a slightly lighter brown).  Generally speaking, however, tule elk are overcome in maximum size by both Rocky Mountain elk and the great Roosevelt elk.  A good sized Roosevelt bull, the largest of the subspecies, can reach 1,000 pounds or more.  Tule elk are the smallest subspecies; in fact, at one time they were colloquially referred to as ‘dwarf elk’.  A large bull tule elk will tip the scales at about 700-800 pounds (hardly a ‘dwarf’ by any means), yet under ideal conditions they may grow larger.

The tule elk, the smallest of the elk subspecies, are best adapted to open country and semi-desert conditions among elk races (McCullough 1969).  Image source: CDFW

Tule elk once roamed the San Jaoquin Valley in ample numbers.  Early settlers found tule elk roaming the foothills of the Sierra Nevada west to the central Pacific coast and from the headstream of the Sacramento River south to the Tehachapi Mountains.  Much like the affliction of the American bison on the Great Plains, tule elk became a casualty of human settlement — particularly after the Gold Rush.

Unregulated market hunting, competition with livestock, and the introduction of nonnative plant species all contributed to the decline of tule elk.  What was more devastating, however, was the conversion of elk habitat to agricultural land.  When settlers turned to the plow not only did it remove food and cover resources for elk, it also brought about direct conflict between elk and farmers.  Increasing crop and fence damage fueled campaigns for the removal of the tule elk by those individuals whose livelihoods were affected.  By the time elk hunting was banned by the state legislature in 1873, it was unknown if any tule elk even remained.

Luckily tule elk did remain, thanks in part to the protection provided by California cattle baron Henry Miller.  In 1874 a pair of Tule elk was discovered on the Miller and Lux Ranch by a local game warden at Button Willow.  Miller set aside 600 acres (near present day Tule Elk State Natural Reserve) to give the elk a chance to rebound.  In 1914, the elk had experienced such growth in numbers that Miller requested the California Fish & Game Commission work to relocate the elk from his ranch.

In order to relieve Miller from elk damage to his property and crops (reportedly estimated at $5,000 per year), the U.S. Biological Survey attempted to relocate tule elk by lassoing them from horseback and transporting them to new areas, with little success.  From 1914 to 1934 the California Academy of Science took on tule elk relocation activities 21 times over the next several decades.  These attempts were not very successful either, although they did contribute to establishing the herds at Owens Valley, Cache Creek, and the Tupman Reserve.

From 1971 through 1989 complete species protection was granted to tule elk.  State and Federal laws were passed to prohibit hunting of tule elk until a population of at least 2,000 was reached.  Habitat improvement programs combined with an aggressive reintroduction campaign by the Department of Fish & Game and other state and federal agencies yielded a significant increase in California’s tule elk population.

Tule elk of the San Luis National Wildlife Refugre, circa 1970s.  Image source: BLM 3rd Annual Report to Congress on The Tule Elk.

Tule elk of the San Luis National Wildlife Refuge, cca the 1970s. Image source: BLM 3rd Annual Report to Congress on The Tule Elk, March 1, 1979.

Today there are twenty-two tule elk herds in the Golden State, totaling around 4,200 individuals with the population trending upward.

Due to competing land use practices, it is not easy for tule elk to freely move between sub-populations; this requires the Department of Fish & Wildlife to take action in order to meet statewide management objectives.To help maintain healthy herds, every so often CDFW is tasked with capturing and relocating healthy elk to different established

Dr. Annette Roug (right, kneeling) leads a team of biologists as they attempt to weigh a cow elk.  Photo credit: Joe and Nancy Rodrguez.

Dr. Annette Roug (front right) leads a team of biologists as they attempt to weigh a cow elk. Photo credit: Joe and Nancy Rodrguez.

herds.  Removing elk from one herd and placing them in another helps to simulate the natural movement of individuals between herds which increases genetic diversity, an important function of a healthy population.

The Wildlife Investigations Lab took part in one such capture and relocation effort at the end of March.  A total of 36 elk were captured via helicopter from the San Luis National Wildlife Refuge near Los Banos.  Once elk were netted from the helicopter, they were processed by capture teams.  Capture teams took measurements, collected hair, blood, and other biological data to assess the health of the herd before they moved on to their new locations.

The animals were successfully released to join their new herds.  A portion of the captured animals were also radio-collared to collect post-release movement information.

An elk sets eyes on joining its new herd.  Photo courtesy of Joe and Nancy Rodriguez.

An elk sets sights on joining its new herd. Photo courtesy of Joe and Nancy Rodriguez.

To read the CDFW news release from this successful capture, click here.

For more information on the CDFW Elk Program, click here.

Interested in more tule elk biology?  Click here.



Throwback Thursday: An Unusual Sea Otter Study

By Tom Batter, WIL Scientific Aid

Happy Throwback Thursday loyal readers!  Today we highlight an article describing an experimental approach by DFG to help curb losses to the abalone industry.  The experiment called for DFG to partner with commercial fisherman to supplement feed to the sea otter populations off the coasts of Monterey and San Luis Obispo counties.  The goal in mind was to make the sea otter’s southern migration unnecessary to help boost abalone production.  Quite an interesting approach that, to this author’s knowledge, was ineffective.  This excerpted page originally appeared in the 1967 November-December issue of Outdoor California.


Wintertime in Vole Country

By Austin Roy – Scientific Aid

Amanda Poulsen, a graduate student from UC Davis and CDFW volunteer, with an Amargosa vole (Microtus californicus scirpensis) after recording demographic data and applying a numbered ear tag.

Amanda Poulsen, a graduate student from UC Davis and CDFW volunteer, with an Amargosa vole (Microtus californicus scirpensis) after recording demographic data and applying a numbered ear tag.

Winter is usually a time to cozy up in front of the fire with a cup of hot chocolate, but winter for the endangered Amargosa vole (Microtus californicus scirpensis) is a totally different story.  These elusive desert rodents do not hibernate like some other mammals.  They work during the cold winter nights (as low as 5F /-15C) and cool days in search of food.  Because of their yearlong activity, the work at WIL doesn’t slow down over winter either.

Researcher looking for predator tracks around known vole habitat near Tecopa, CA.

Greta Wengert Ph.D., a collaborator from the Integral Ecology Research Center, looks for predator tracks around known vole habitat near Tecopa, CA.

Little is known about Amargosa vole behavior and biology.  Most of the information available is derived from the Amargosa vole’s cousin, the California vole (Microtus californicus).  To remedy our lack of knowledge, a team of researchers and volunteers from WIL, UC Davis, and USGS continues to work through the winter to try to learn more about the Amargosa vole.

A track plate box used to record predator tracks

A track plate box used to record predator tracks

Our project involves monitoring the vole population by live-trapping the voles.  This trapping allows for us to assess the health of individual voles, record demographic data (age, sex, weight, etc.), give voles individually marked ear tags, and then release the animals back into their environment.  This type of research allows us to track changes in the population and get an understanding of the geographic range of the vole.  In addition to “hands-on” research, I am also involved with “hands-off” surveillance.  Non-invasive techniques such as looking for vole sign (feces and runways), water sampling, and recording vegetation allow me to gain information about the vole and its habitat while creating as little impact as possible.

A bobcat (Lynx rufus) captured on a trail camera near Tecopa, CA

A bobcat (Lynx rufus) captured on a trail camera near Tecopa, CA

Also, over the winter months I am continuing to gather data on the predators of the Amargosa vole.  Recent findings from USGS suggest that predation might be a limiting factor to the vole’s persistence in its environment.  In response to this finding I began a study to observe and document predators.  I am deploying trail cameras and once a month I conduct point counts to record predator species that utilize vole habitat.  With the help of volunteers, I am also collecting predator feces and pellets.  This allows us to examine the diet of predators and identify which predator species are eating the vole.

The Amargosa vole display recently installed in the Shoshone Museum, in Shoshone, CA.

The Amargosa vole display was recently installed by CDFW and UC Davis in the Shoshone Museum, in Shoshone, CA.

All of this information is well worth the discomfort of working through cold weather.  The data we collect is being applied to the management of the vole  and will aid researchers in understanding how to best help this imperiled animal.  For this reason, we happily bundle up, heat up some tea for our travel mugs, and embrace the weather as we continue to do our best to help the Amargosa vole survive in such an extreme environment.

Got Acorns?

If you have acorns in your area, be on the look out for band-tailed pigeons this winter. Band-tailed pigeons are California’s only native pigeon and this time of year, they will fly great distances to find acorns. Band-tailed pigeons are one of the rare bird species that will actually swallow acorns whole! Unfortunately, this behavior also makes them more susceptible to Trichomonosis, a disease caused by a single-celled microscopic protozoan parasite, Trichomonas gallinae.

Band-tailed pigeon. Photo by Krysta Rogers.

Adult band-tailed pigeon showing the characteristic white crescent and iridescent greenish-bronze patch of feathers on the hind neck and black band on the tail, for which the species was named. Photo by Krysta Rogers, 2013.

The parasite lives in the mouth and throat of infected birds, causing caseous (“cheese-like”) lesions to develop in the bird’s mouth or esophagus. As the lesions become larger, the pigeons can no longer swallow acorns, leading to weight loss and eventually death. The lesions also may cause the pigeon to suffocate, if they block the airway.

Band-tailed pigeons with Trichomonosis. Photos by Jeff Cann & Krysta Rogers.

Fig. 1: A band-tailed pigeon showing signs of infection with Trichomonosis.
Fig. 2: A dead band-tailed pigeon observed during a Trichomonosis die-off in 2012.
Fig. 3: Caseous lesions in the oral cavity of a band-tailed pigeon with Trichomonosis.
Photos by Jeff Cann (Fig. 1) & Krysta Rogers (Fig. 2 & 3).

While this disease can make pigeons sick any time of the year, large-scale die-offs only occur during the winter, in some years. The last series of mortality events were reported in 2012 in California, when up to 10,000 pigeons were estimated to have died between December and March. Recent research by CDFW suggests that these mortality events are more likely to occur in winters with low precipitation, similar to the conditions we’ve been experiencing so far this winter.

So, if you have acorns, be on the lookout for band-tailed pigeons and enjoy watching them comically hang from the branches as they try to reach an acorn. Hopefully, the pigeons will not experience any die-offs this winter. However, if you do happen to see pigeons that appear sick, such as showing signs of weakness, labored breathing, breathing with their bill open, drooling, reluctance to fly when approached, or are dead, you can help by reporting the mortality to the Wildlife Investigations Lab.

If you have any questions, or would like to report sick or dead band-tailed pigeons, contact Krysta Rogers at 916-358-1662.