Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
CARLSBAD FWO: Story of Hope for the Pacific pocket mouse at Dana Point Preserve, California
California-Nevada Offices , July 30, 2009
Print Friendly Version
Pacific pocket mouse
Photo: Mark Pavelka/USFWS
Pacific pocket mouse Photo: Mark Pavelka/USFWS - Photo Credit: n/a



by Stephanie Weagley, Carlsbad FWO
For approximately 20 years, the Pacific pocket mouse could not be found on the marine terraces of the southern California coast. Then in 1993, 36 individuals were captured at the Dana Point Headlands in Orange County. 


“The rediscovery came at a time when the Service thought the animal was gone,” said Will Miller, a biomonitor with the Carlsbad Fish and Wildlife Service Office. “It is the only known remaining site for the Pacific pocket mouse on private lands.” The other two populations known to exist are on Marine Corps Base, Camp Pendleton in San Diego County. They were discovered in 1995, but since that time, no additional populations have been found.  


Historically, nine Pacific pocket mouse populations existed along the southern California coast from Los Angeles County south to the Mexican border in San Diego County.  One of the smallest subspecies of pocket mice, the nocturnal animal prefers sandy soils and open coastal sage scrub habitat located no more than 2.5 miles from the Pacific Ocean.


Since its reappearance, the Service has been pursuing the recovery of the species. Shortly after its rediscovery, the Service federally listed the Pacific pocket mouse as endangered in 1994. Following the listing, partnerships were formed with the landowners of the Dana Point Headlands, the Center for Natural Lands Management, California Department of Fish and Game (CDFG), and other individuals to help recover the Pacific pocket mouse.  Through these partnerships, additional species protections and habitat enhancements have been achieved.


On-the-ground conservation efforts began in 1996 when the Service and the CDFG entered into a conservation agreement with the private landowners of Dana Point Headlands through the Orange County Central-Coastal Natural Community Conservation Plan/Habitat Conservation Plan (NCCP/HCP).  The plan established an eight year, 22-acre temporary Preserve on the 121-acre Dana Point Headlands site while allowing the owners to conduct compatible development activities.  It also provided the Service and CDFG an option to purchase the temporary Preserve and an opportunity to conduct crucial management activities. 


Population monitoring, invasive weed removal, coastal sage scrub thinning, and native vegetation seeding began following adoption of the NCCP/HCP and continued for several years within the temporary Preserve.  However, after these initial habitat enhancement efforts, there was troubling news; population numbers appeared to be less than what had been previously detected in 1993.


Consequently, the Service and CDFG decided to conduct extensive trapping efforts throughout the entire 22-acre temporary Preserve in order to gain a better estimate of the mouse’s population numbers. Unfortunately, only four individuals were trapped in 2001 (two were pregnant females), and two individuals in 2002. This was alarming news.  “Will was despondent”, said Karen Goebel, Assistant Field Supervisor for the Carlsbad Field Office. “He thought the population was going to blink out.”


After the 2002 findings, more non-native weed removal and reintroduction of native vegetation took place along the entire southeastern border of the temporary Preserve—an area adjacent to residential development. This task was made possible through the efforts of an adjoining homeowner.


In December of 2005, the landowners of the Dana Point Headlands and the Harry and Grace Steele Foundation permanently protected the temporary Preserve through a collaboration with the Center for Natural Lands Management (CNLM). The CNLM, a non-profit land management organization from southern California, purchased the Preserve through a generous 15 million dollar donation given by the Harry and Grace Steele Foundation.  The Foundation's desire was to establish an endowment and preserve this portion of the Dana Point Headlands in perpetuity, as well as to conserve its natural resources for the ongoing enjoyment of the public. “It provided the Preserve with permanent protections and management compatible with the pocket mouse’s long term conservation,” Miller said. “It further meant the Service and CDFG no longer needed to worry how they were going to exercise their option to purchase the Preserve. This was an unexpected and welcome surprise.”


As part of the Preserve’s acquisition, the Foundation requested permission to construct a perimeter trail within the Preserve for public use. Permission was granted and trail construction began in 2007, but not without worry. The Service was concerned that trail construction might push the low population numbers even lower. However, activities continued to enhance habitat through non-native weed removal, native plant seeding efforts, and abandonment and restoration of a road needed to create a bigger Preserve.  With Service input, the CNLM also initiated a new PPM population monitoring program that involved random sampling of approximately two-thirds of the Preserve each year.  Each person remained hopeful that after all the efforts to conserve the Dana Point Headlands, more mice would be caught. 


Remarkable news came in 2008. Survey results detected the largest increase of Pacific pocket mice numbers ever witnessed at Dana Point. In May of 2008, 14 adults were detected, and in June, 17 were detected. Only one of the individuals captured in June had previously been captured in May.  This meant 30 individuals were detected within an area smaller than what was sampled in 2002.  Equally important, 16 of the individuals detected in May were young of the year, indicating that 2008 was a good year for reproduction. “This was an astonishing result,” said Miller. “Population estimates were now close to the number of individuals initially detected on the site in 1993.” The excellent news did not stop here.


The most dramatic population increase came in 2009 when 82 individuals were found!  “These were the same areas surveyed in 2008,” said Miller. “This is great news for the population at Dana Point.  With the removal of a road, habitat enhancement and reproducing mice, we now have hope that with continuing management, the population at Dana Point will remain stable. What a contrast from the detection of just two individuals in the summer of 2002.”


“Despite your struggles, never give up, keep working hard with your partners, and have hope,” said Goebel. 


Although protection and management activities have taken place over the past 15 years, the mouse remains in danger of extinction due to habitat loss and fragmentation, limited population numbers, and depredation by domestic and feral cats.


Over 85 animal and 120 plant species call the Dana Point Preserve (now 29.4 acres) home. In addition to the Pacific pocket mouse, species include:  federally threatened coastal California gnatcatcher, coastal sage scrub, California box thorn, short-eared owl, orange-throated whiptail lizard, bobcat, coastal cactus wren, red coachwhip snake, and peregrine falcon.






Contact Info: Stephanie Weagley, 805-644-1766, stephanie_weagley@fws.gov
Find a Field Notes Entry

Search by keyword

Search by State

Search by Region

US Fish and Wildlife Service footer