Goal: Increase the abundance of nesting burrowing owls to ensure that there are multiple (=2) interbreeding self-sustaining nodes (primarily utilizing natural burrow systems) on Conserved Lands that will provide for burrowing owl persistence in the MSPA over the long-term (>100 years).
Management units: 3, 4, 5, 6, 9
Continue the research study of breeding burrowing owls, foraging, threats, artifiical and natural burrows, movements, and habitat assessments to inform management at existing occupied and future potential nodes. Include translocated owls in the study to determine effectiveness of translocation and to gather information to inform continued management at new nodes.
|RES-1||Submit project metadata, survey data, and report with management recommendations to the MSP web portal.||In progress|
|Burrowing Owl Surveys and Reports Completed by 2021.||2021|
Management units: 3, 4, 5, 6, 9
As part of the burrowing owl research study, collect genetic samples to determine origin of owls and genetic population structure compared to other populations in California, Mexico, and the western U.S.
|RES-1||Continue to collect genetic samples during surveys for burrowing owl for use in examining the genetic relationship of burrowing owl in California, Mexico, and the western U.S.||waiting for precedent action|
|RES-2||Analyze the genetic samples to evaluate the degree of genetic variation within and between populations and to possibly identify genetic bottlenecks or barriers.||waiting for precedent action|
|RES-3||Prepare management recommendations based upon the genetic analysis that maintain or enhance gene flow and genetic diversity and that identifies source populations.||waiting for precedent action|
|RES-4||Submit project metadata, datasets, and Burrowing Owl Genetics Study report to the MSP Web Portal.||Unknown|
|Genetic samples collected from studies completed through 2021; Genetic Analysis and Report Completed by 2021.||2021|
|Threat Name||Threat Code|
|Loss of connectivity||LOSCON|
Management units: 3, 4, 5, 6, 9
Annually inspect artificial and natural burrows and occupied habitat to determine management needs using a regional IMG protocol. The monitoring should include considerations for retrofitting existing artificial burrows with the most current design to maximize fledgling success, removal/closing of burrows at poorly performing sites, and addition of burrows to maximize success.
|IMP-1||Conduct regional IMG monitoring protocol survey locations and habitat, assess status, and quantify potential threats.||available for implementation|
|IMP-2||Based upon occurrence status and threats, determine management needs including whether routine management or more intensive management is warranted.||available for implementation|
|IMP-3||Submit monitoring and management data to the regional MSP web portal.||available for implementation|
|Surveys Completed Annually with management recommendations||2021|
Management units: 3, 4, 5, 6, 9
Conduct management actions identified through the IMG regional protocol monitoring, including protecting populations from disturbance, removing invasive plants, cleaning, repairing, and fortifying burrows within the known occupied and suitable habitat, retrofitting existing artificial burrows with the most current design to maximize fledgling success, removal/closing of burrows at poorly performing sites, and addition of burrows to maximize success.
|IMP-1||Perform management activities such as protecting populations from disturbance, removing invasive plants, cleaning, repairing, and fortifying burrows, retrofitting existing artificial burrows with the most current design to maximize fledgling success, removal/closing of burrows at poorly performing sites, and addition of burrows to maximize success..||some occurrences are in progress|
|IMP-2||Submit project metadata and management data to MSP web portal.||some occurrences are in progress|
|Management Completed as Needed Based Upon Monitoring Recommendations||2021|
Management units: 3, 4, 5, 6, 9
In 2017, finalize the Burrowing Owl Conservation and Management Plan that includes results from the research study and habitat assessments and recommendations for the establishment of at least two nodes and enhancement of existing occurrences to ensure persistence on Conserved Lands and establishment of a captive breeding population as a source for burrowing owls.
|PRP-1||Consult with the Burrowing Owl Working Group consisting of species experts, scientists, wildlife agencies, land managers and other stakeholders to gather input into prioritized management actions.||completed|
|PRP-2||Submit project metadata and Burrowing Owl Conservation and Management Plant to the MSP Web Portal.|
|Burrowing Owl Management Plan Completed in 2017||2021|
Management units: 3, 4, 5, 6, 9
Beginning in 2017, implement highest priority management actions from the Burrowing Owl Conservation and Management Plan.
|IMP-1||Submit project metadata, management datasets, and report to the MSP Web Portal.||available for implementation|
|By 2021, =1 High Priority Management Action Implemented from the Burrowing Owl Conservation and Management Plan||2021|
Management units: 3, 4, 5, 6, 9
Beginning in 2017, monitor the effectiveness of management actions implemented for western burrowing owl on Conserved Lands.
|IMP-1||Submit monitoring data and reports to MSP web portal||waiting for precedent action|
|Monitoring Completed and Data and Report Submitted within one year of management actions||2021|
An Adaptive Management Approach to Recovering Burrowing Owl Populations and Restoring a Grassland Ecosystem in San Diego County
San Diego Zoo Institute for Conservation Research (ICR), in partnership with multiple agencies, has developed an adaptive conservation management program to assist in the recovery of Western Burrowing Owls (BUOW; Athene cunicularia hypugaea) and their grassland ecosystem in San Diego County. Main objectives include (1) establishing more natural grassland ecosystems in San Diego County by re-establishing ground squirrels that provide critical resources for BUOW and valuable ecosystem engineering effects; (2) better understanding of the factors regulating BUOW population dynamics; (3) developing a comprehensive strategic management plan for BUOW in San Diego County; and (4) implementing the strategic management plan to begin establishing additional breeding nodes of burrowing owls. In 2017 ICR partnered with SDMMP to make publicly available a BUOW Conservation and Management Plan for San Diego County. This is a living document developed with input from local, state, and federal wildlife agencies, and will continue to be updated in the future.
Burrowing Owl Artificial Burrow Surveys- CDFW 2010- 2012
Artificial burrows for the western burrowing owl were surveyed in 2010, 2011, and 2012 by the California Department of Fish and Wildlife (CDFW). Each burrow was surveyed for evidence of burrowing owl use. Types of evidence included whitewash, prey remains, feathers, pellets, or visual confirmation of the species. Burrows with strong or multiple types of evidence were marked as used by burrowing owls. Maintenance needs were also recorded for each burrow. Survey results: http://arcg.is/2dDPFsS
Burrowing Owl Monitoring Analysis and Protocol
The overall purpose of this study was to evaluate the methodology of the 2010 burrowing owl survey protocol. The specific purpose of the analysis presented here is to use data collected according to the burrowing owl monitoring protocol to estimate occupancy for both burrowing owls and California ground squirrels within the sample frame. The expected detection probability for owls was much lower than anticipated. In general, efforts should be made in future studies to increase detection probability for both owls and squirrels. Possible ways to improve detection include (a) better training of field personnel, (b) more consistent application of the monitoring protocols, (c) changes in the protocol such as the number of visits per site or the time spent at a site during each visit, and (d) improved field equipment and consistent used of the same equipment. If this work is to be repeated in the future, the monitoring protocol should more clearly describe the method for collecting ground squirrel data. Habitat covariates associated with suitable burrowing owl habitat were not able to be identified. In the future, conceptual models need to be developed to guide data collection and analysis, with attention to the spatial and temporal scale of the covariates related to habitat suitability.
Burrowing Owl Monitoring and Adaptive Management
Our objective was to implement short-term treatments, including squirrel translocation, to re-establish key ecological processes on protected reserve lands. We manipulated vegetation and squirrels in a replicated, large-scale field experiment for two years, and monitored through a minimum of three years. Vegetation mowing and soil decompaction treatments reduced grass density and thatch depth. Squirrel translocation accelerated squirrel settlement and activity in target sites. Of the more than 1000 burrow entrances remaining through the third year, nearly all burrows were concentrated in the plots that received squirrel translocation. Noteworthy and persistent engineering effects were achieved through squirrel activity, and both vegetation management and squirrel re-establishment were needed to stimulate squirrel activity. The overarching goal of this experiment was to provide conservation managers with a cost-effective tool for restoring degraded habitats to a hybrid ecosystem state with improved suitability for species of conservation concern, in this case western burrowing owl (Athene cunicularia hypugaea).
Burrowing Owl Recovery- Camera Traps
An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County; camera trapping at burrowing owl nest entrances; productivity; reproductive success; predation; prey; foraging
Regional Grazing Monitoring Plan
This project evaluates using grazing as a management tool for degraded grasslands and coastal sage scrub habitat. Pilot projects will be conducted to look at the efficacy of grazing as management tool and necessary monitoring techniques.
SR 94 Wildlife Infrastructure Plan
Proposed road improvements to SR 94 provide an opportunity to mitigate the potential barrier effects of the highway. This project identifies where improvements to existing infrastructure on SR-94 could improve connectivity across the South County preserves, using Best Management Practices from the scientific literature; recommends wildlife movement monitoring to identify where new crossings are needed; and identifies where additional conservation would enhance the integrity of South County linkages. The review prioritizes infrastructure improvements of 35 existing undercrossings inspected by wildlife experts in the field along 14.6 miles of SR-94 where the highway bisects conserved lands. The majority of the recommendations for infrastructure improvement focus on increasing the diameter, and thus the openness ratio (cross-sectional area divided by length), of the undercrossing itself, removing vegetation and debris blocking the undercrossing, restoring habitat in the approach to the undercrossing, and installing fencing to both (1) keep animals off the highway and (2) funnel wildlife to the undercrossings.
Vernal Pool Restoration
The vernal pools at the Spring Canyon/Goat Mesa complex (J16-J18) and surrounding open space have suffered considerable off-road damage over the years. This damage has resulted in changes in hydrologic, flow patterns, and inundation characteristics. This vernal pools complex was identified by the adopted Recovery Plan for Vernal Pools of Southern California (USFWS 1998) as necessary to stabilize populations of the following endangered and threatened MSP species: E. aristulatum, P. nudiuscula, N. fossalis, O. californica, B. sandiegonensis, and S. wootoni. The Management Strategic Plan (MSP) for Conserved Lands in Western San Diego County (SDMMP) also lists other MSP species historically found onsite, including D. variegata, M. minimus, S. hammondii, and A cunicularia. Minimization of illegal off-road vehicle use is the primary goal. The main objective to reach the goal is to use to fence off as many of the key access points and areas of frequent off-road vehicle use throughout the City open space to protect the habitat for the endangered and threatened species that exist onsite. This will be done by hiring a fence contractor to provide all supplies and install the fence.
|File name||Lead Author||Year||Type|
|2021 BUOW Nesting Ecology and Node Expansion||San Diego Zoo Wildlife Alliance||2021||powerpoint presentation|
|An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County, Project Report 2011||2011||report|
|An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County, Project Report 2012||2012||report|
|An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County, Project Report 2013||2013||report|
|An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County, Project Report 2014||2014||report|
|An Adaptive Management Approach to Recovering Burrowing Owl Populations and Restoring a Grassland Ecosystem in San Diego County: A Proposal for Funding to the San Diego Foundation||Swaisgood, Ronald R.; Shier, Debra M.; Nordstrom, Lisa A.; Endress, Bryan; San Diego Zoo Institute for Conservation Research; Lieberman, Alan||2010||other|
|Burrowing Owl Habitat Conservation and Management Plan for San Diego County||McCullough Hennessy, Sarah; Wisinski, Colleen; Shier, Debra M.; Nordstrom, Lisa A.; Swaisgood, Ronald R.; Montagne, J.P.; Marczak, Susanne||2017||report|
|Burrowing Owl Monitoring Analysis and Protocol: An Analysis of burrowing owl (Athene cunicularia) occupancy in south coastal San Diego County||2010||report|
|Burrowing Owl Partners Management, Nov 27, 2012||2012||powerpoint presentation|
|Burrowing Owl Priority Objectives for 2017-2022||2017||other|
|County of San Diego MSCP Monitoring Summary Report January 1998 - June 2007||County of San Diego||2007||report|
|Final Report: Burrowing Owl Conservation Breeding and Release Preparation||2020||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County Task B||2012||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County Task B||Deutschman, Douglas; McCullough, Sarah||2011||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County Task C||2013||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County Task C||Deutschman, Douglas; McCullough, Sarah||2011||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County Task D||2012||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County Task E||2014||report|
|Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in Southern San Diego County: Exhibit A - Scope of Work||2010||other|
|Project Report 2015 An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County||McCullough Hennessy, Sarah; Wisinski, Colleen; Montagne, J.P.; Shier, Debra M.; Swaisgood, Ronald R.; Nordstrom, Lisa A.||2015||report|
|Project Report 2016: An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County||Wisinski, Colleen; Hennessy, Sarah; Montagne, J.P.; Marczak, Susanne; Stevens, Michael; Hargis, Jacob; Shier, Debra M.; Swaisgood, Ronald R.; Nordstrom, Lisa A.||2016||report|
|Ramona Grasslands Conservation Bank Burrowing Owl Translocation Overview||Pollett, Kathleen||2021||powerpoint presentation|
|San Diego Annual Burrowing Owl Meeting - Santa Clara County Burrowing Owl Conservation||Santa Clara Valley Habitat Agency; Talon Ecological Research Group||2021||powerpoint presentation|
|Status Assessment and Conservation Plan for the Western Burrowing Owl in the United States||Ayers, Loren W.; Klute, David S.; Howe, William H.; Sheffield, Steven R.; Jones, Stephanie L.; Zimmerman, Tara S.; Green, Michael T.; Shaffer, Jill A.||2003||report|
|The status of the Burrowing Owl in San Diego County, California||Bloom, Peter; Lincer, Jeffery||2007||journal article|
|Western Burrowing Owl Genomics||Barr, Kelly; Bossu, Christen; Smith, Tom; Ruegg, Kristen||2021||powerpoint presentation|
Found from southern interior British Columbia (nearly extirpated), southern Alberta, southern Saskatchewan (extirpated from a portion of the province), and southern Manitoba (extirpated from a portion of the province), south through eastern Washington, central Oregon, and California to Baja California, Mexico and east to western Minnesota, northwestern Iowa, eastern Nebraska, central Kansas, Oklahoma, eastern Texas, and Louisiana, and south to central Mexico .
Within the MSPA winters in MUs 1, 2, 3, 4, 5, 6 and 9 . Breeding owls are currently restricted to Otay Mesa and vicinity and to Ramona Grasslands. Outside the MSPA, Naval Base Coronado also supports breeding owls.
Occurs in shortgrass prairies, grasslands, lowland scrub, agricultural lands (particularly rangelands), prairies, coastal dunes, desert floors, and some artificial, open areas as a year-long resident. They require large open expanses of sparsely vegetated areas on gently rolling or level terrain with an abundance of active small mammal burrows. As a critical habitat feature need, they require the use of rodent or other burrows for roosting and nesting cover . In San Diego County, California ground squirrels (Otospermophilus beecheyi) are critical ecosystem engineers, providing burrows for burrowing owls . Ground squirrels have declined in the county and efforts are being made to reintroduce squirrel populations and to develop and implement best management practices to enhance squirrel habitat in order to provide more breeding habitat for owls. Management of squirrel and owl habitat includes controlling non-native annual grasses which degrade habitat quality by growing too tall and dense.
Variously placed in the monotypic genus Speotyto or in Athene, where it has three congeners .
The burrowing owl is primarily a diurnal species with crepuscular hunting habits . They may move the location of their perch in order to thermoregulate by perching in open sunlight in early morning and then moving to shade or to the burrow, when temperatures are hot .
Breeding occurs from March through August, with a peak in April and May; the clutch size is 6-11 eggs, with an average of 7-9 eggs; this clutch size may increase to the north . The young emerge from the burrow at about two weeks, and they fly by about four . A study of breeding owls on Otay Mesa in San Diego County documented low productivity during drought with incidence of infanticide and predation as major sources of chick mortality . Habitat quality likely affects prey availability which is linked to infanticide and predators such as corvids may be subsidized by human activities. The study compared microhabitat characteristics at artificial and natural burrows and found that artificial burrows did not maintain a stable microclimate, whereas natural burrows did and were better able to buffer nests from changes in external air temperature and humidity.
Diet is composed of a variety of foods included Peromyscus, Microtus and beetles; they also may take reptiles, birds, and carrion [1,9]. They are a crepuscular hunter and hunt by using short flights, running along the ground, hovering or by using an elevated perch from where prey is spotted. They typically forage in short-grass, mowed, or overgrazed pasture, golf courses and airports . In the Otay Mesa study, home range movements were monitored using GPS data loggers and owls were found to have very restricted foraging areas centered around the nesting burrow . There was substantial difference in foraging success between home ranges and owls did not attempt to expand foraging activities into higher quality habitat.
A total of 92 percent of 555 owls that were banded at a nesting area were never re- encountered after the year in which they were banded. The 8 percent that returned to the natal area after being banded, returned one or more years after banding and stayed in the natal area for 2 to 4 breeding seasons.7 Returns of one year old owls were located 2.4 to 26.4 kilometers from the natal nest .
Conversion of grassland to agriculture, other habitat destruction, predators, collisions with vehicles, and pesticides/poisoning of ground squirrels. [8, 10, 11]
Special considerations: excerpted from the Western Riverside Co. MSHCP (see  and citations within) - The importance of retaining colonies must be stressed, as this species appears to have evolved as a colonial species in association with burrowing mammal communities (Dyer 1987). Minimum viable colony size is unknown. While these owls appear to adapt fairly well to human presence in some cases, i.e., airport runways and other human modified open spaces, the continued presence of active mammal-created burrows is essential. In Oklahoma, the removal of prairie dogs allowed deterioration of burrows, making them unsuitable for nest burrows after one year (Butts 1973). Rodent eradication programs may reduce the consistent availability of high and moderate function habitat. The remaining habitat is often roadside drainage ditches, increasing potential for significant losses to vehicle collisions (Remsen 1978). The available soil type appears to be a factor in nest burrow selection.
 Haug, E. A., B. A. Millsap, and M. S. Martell. 1993. Burrowing Owl (Speotyto cunicularia). In The Birds of North America, No. 130 (A. Poole and F. Gill, Eds.) . Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 MSP-MOM. 2016. Management Strategic Plan Master Occurrence Matrix. http://sdmmp.com/reports_and_products/Reports_Products_MainPage.aspx
 Wisinski, C., J.P. Montagne, S. Marczak, D.M. Shier, L.A. Nordstrom, and R.R. Swaisgood. 2012. Project Report 2-12: An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County. Report prepared for the San Diego Foundation Otay Mesa Grassland Mitigation Fund.
 Deutschman, D. and S. McCullogh. 2013. Monitoring and Adaptive Management of Burrowing Owl on Conserved Lands in South San Diego County: Task C for 2012: Data Analysis and Synthesis. Report prepared for the San Diego Association of Governments.
 Thomsen, L. 1971. Behavior and ecology of burrowing owls on the Oakland Municipal airport. Condor 73: 177-192.
 Coulombe, H.N. 1971. Behavior and population ecology of the burrowing owl, Speotyto cunicularia, in the Imperial Valley of California. Condor 73: 162-176.
 Bent, A. C. 1938. Life histories of North American birds of prey. Part 2. U.S. Natl. Mus. Bull. 170. 482pp.
 Zarn, M. 1974. Burrowing Owl, Report No. 11. Habitat management series for unique or endangered species. Bureau of Land Management, Denver. 25 pp.
 Swaisgood, R.R., C. Wisinski, J.P. Montague, S. Marczak, D.M. Shier, and L.A. Nordstrom. 2014. Project Report 2014: An adaptive management approach to recovering burrowing owl populations and restoring a grassland ecosystem in San Diego County. Report prepared for the San Diego Foundation Otay Mesa Grassland Mitigation Fund.
 Marti, C. D. 1974. Feeding ecology of four sympatric owls. Condor 76: 45-61.
 Lutz, R. S., and D. L. Plumpton. 1999. Philopatry and nest site reuse by burrowing owls: implications for productivity. J. Raptor Research 33: 149-153.
 Remsen, J. V., Jr. 1978. Bird species of special concern in California. Calif. Dep. Fish and Game, Sacramento. Wildl. Manage. Admin. Rep. No. 78-1. 54pp.
 Grinnell, J. and A.H. Miller. 1944. The Distribution of the Birds of California. Pacific Coast Avifauna Number 27. Copper Ornithological Club, Berkeley, California. Reprinted by Artemisia Press, Lee Vining, California; April 1986. 617 pp
 Riverside County. 2003. Western Riverside County Multiple Species Habitat Conservation Plan (MSHCP). Final MSHCP, volume II. Prepared for County of Riverside County Transportation and Lands Management Agency by Dudek & Associates, Inc. Approved June 17, 2003.