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Wednesday, May 21, 2014

WILDLIFE WEDNESDAY- Announcing our new bundle of joy!, by Conservation Science Director Dr. Mike White

Newborn fawn F1- 5.15.14, AKA "Fuzz Butt," photo courtesy of Bill Lydecker

We would like to welcome and announce the arrival of our first pronghorn fawn of the season!  Baby F1-5.15.14 (AKA “Fuzz Butt”) was seen by Conservancy Naturalists Bill Lydecker and Vicki Bingaman on May 15.  Bill and Vicki have been conducting driving surveys for pronghorn to document their distribution and numbers, which has been a big help in advancing the Conservancy’s understanding of this species on Tejon Ranch.  Even better, using Bill’s excellent photos of the pronghorn, Bill and Vicki have been able to identify unique horn structures and coat patterns that allow them to recognize individuals.  For example, compare the photos of the two males B1-4.8.14 and B1-4.15.14 and note the differences in the amount of white on the necks.  These are clearly two different bucks.  Therefore Bill and Vicki know that female D1-5.8.14 looked pregnant on May 8, and then they saw the same female with a fawn on May 15.  This is incredibly valuable information that greatly enhances the ability of the Conservancy to monitor the pronghorn herd at Tejon Ranch.
Male B1- 4.15.14, photo courtesy of Bill Lydecker

Male B1- 4.08.14, photo courtesy of Bill Lydecker

Pronghorn (Antilocapra americana) is the sole member of the family Antilocapridae.  They are often referred to as “antelope” (in fact the Antelope Valley was named after these guys), but they are unrelated to Old World antelope which are in a different taxonomic family.  Pronghorn are the fastest North American land mammal; cruising at 30-40 mph and reaching top speeds of 45 mph.  The probably evolved to outrun American cheetahs, a species that went extinct about 12,000 years ago.  However, new-born fawns are not mobile for 5 days or so; and thus are most vulnerable to predators during that period.  Females typically give birth to their fawns in shrubs or other vegetation to hide them until they are able to run.
Female D1- 5.08.14, photo courtesy of Bill Lydecker

Female D1- 5.08.14, photo courtesy of Bill Lydecker

Pronghorn were very abundant in parts of California prior to European settlement.  They were extirpated from the Antelope Valley and southern San Joaquin Valley by the turn of the 20th Century.  Pronghorn were reintroduced to Tejon Ranch in the 1970s.  The Tejon Ranch herd is currently the southernmost herd in California.  We believe the herd on Tejon Ranch may number in the low 20s of individuals, and the last few years of drought has not helped the populations much.  We also believe that coyotes may be predating new-born fawns before they are up and running.  The surveys that Bill and Vicki are conducting will help us identify important areas of habitat for pronghorn and think about management strategies to enhance their population.  For example, ensuring that there is adequate shrub cover for does to hide their fawns and installing irrigated food plots that can be turned on during drought periods are possible strategies.