2. Michael Galloway Associate Biologist Caltrans, District 11 Environmental Stewardship & Ecological Studies michael.galloway@dot.ca.gov Use of Artificial Burrows by Burrowing Owls at Lonestar West

3.  164 acres: South of State Route 125, North of Brown Field Airport  Mitigation for Vernal Pool and Upland Impacts for Caltrans State Route 11/Otay Mesa East Port of Entry Project  Site Grading (Vernal Pools/Mima Mounds): July 23-August 31, 2012  Mitigation for Burrowing Owls by Artificial Burrow Installation: o Artificial Burrow Locations Randomly Selected Among 205 Installed Mima Mounds o 25 Wood Boxes with Wood Tunnels o 25 Plastic Irrigation Boxes with Corrugated Plastic Drainage Pipe o 25 “Starter Holes” o Installation Occurred from August 29 to September 18, 2012 Lonestar West Mitigation Site  Federal Migratory Bird Treaty Act California “Species of Special Concern” Local Declines in Central and Southern California Breeding Areas Habitat Loss Habitat Degradation/Modification Ground Squirrel Eradication Nesting February 1-August 31 At Lonestar West: Egg-laying: March-May, Hatching-Fledging: April-June  CDFW-Protocol Burrowing Owl Surveys: Breeding Season(April through August): One daylight survey per month Outside Breeding Season: One daylight survey (December) Burrowing Owl March 18, 2011 March 3, 2015

5. Burrowing Owl Numbers and Burrow Usage during the Breeding Season at Lonestar West Burrowing Owl Breeding Activity at Lonestar West Survey YearPlasticWoodStarter Hole Breeding Burrows (# Successful of # Total) Eggs / Chicks / Fledges Reproductive Success (% Fledglings from Eggs) 20130 of 3 19 / 1 / 0 0 % 1 of 3 20 / 8 / 2 10 % 0 0 / 0 / 0 0 % 20142 of 4 27 / 8 / 2 7 % 3 of 8 47 / 18 / 8 17 % 0 0 / 0 / 0 0 % 20152 of 7 47 / 6 / 4 9 % 3 of 6 26 / 13 / 7 27% 0 0 / 0 / 0 0 % Survey YearPlasticWoodStarter HoleAverage # BUOW per Survey Average # Burrows with BUOW or BUOW Sign [90% Confidence Interval] 201316 [11, 21] 13 [9, 18] 1 [0, 3] 14 [9, 19] 201419 [17, 21] 17 [15, 19] 3 [2, 4] 17 [15, 20] 201518 [15, 20] 16 [15, 18] 0 [0, 1] 15 [11, 19]

6. Future Considerations for Burrowing Owl Mitigation  Location of mitigation site near extant populations of burrowing owls and fossorial mammals  At least three to four burrows per individual / pair / family  Armoring entrances in areas where coyotes are present  Buried chicken wire along floors of boxes / tunnels to prevent filling by fossorial mammal digging  Planting of low-lying vegetation on mounds with artificial burrows to 50-150 feet surrounding burrows  Perches???  Monitoring!!!  Plan for contingencies Acknowledgements  CALTRANS: Bruce April, Kim Smith, and Ted Thurston, the Office of Environmental Stewardship and Ecological Studies  SAN DIEGO ZOO INSTITUTE FOR CONSERVATION RESEARCH: Colleen Wisinski, Susanne Marczak, Lisa Nordstrom, and the research technicians  RECON: Meagan Olson and Pete Tomsovic  TIERRA DATA: Jim Kellogg, James Lockman, and Fausto Larios  AECOM: Scott McMillan, Lindsey Cavallero, and Linnea Spears-Lebrun  Jeff Lincer, Jeff Kidd, Doug McKinney

7. USE OF ARTIFICIAL BURROWS BY BURROWING OWLS AT LONESTAR WEST LONESTAR WEST MITIGATION SITE 164 acres: South of State Route 125, North of Brown Field Airport Mitigation for Vernal Pool and Upland Impacts for Caltrans State Route 11/Otay Mesa East Port of Entry Project Nine Active Burrows Used by Burrowing Owls Directly Impacted Mitigation by Installation of Artificial Burrows: 25 Wood Boxes with Wood Tunnels 25 Plastic Irrigation Boxes with Corrugated Plastic Drainage Pipe 25 “Starter Holes” Artificial Burrow Locations Randomly Selected Among 204 Installed Mima Mounds Grading of Site (Vernal Pools/Mima Mounds): July 23-August 31, 2012 Installation of Artificial Burrows: August 29- September 18, 2012 March 18, 2011 March 3, 2015 BURROWING OWL Federal Migratory Bird Treaty Act California “Species of Special Concern” Local Declines in Central and Southern California Breeding Areas Habitat Loss Habitat Degradation/Modification Ground Squirrel Eradication Nesting February 1-August 31 At Lonestar: Egg-laying: March-May Hatching-Fledging: April-June Some are Year-Round Residents at Lonestar CDFW-Protocol Burrowing Owl Surveys : One daylight survey per month during the breeding season (April through August) and one daylight survey outside of the breeding season (December) ComplexPlasticWoodStarter Hole Average # Owls per Survey Owl Use / # of Artificial Burrows Year116 [11, 21] 13 [9, 18] 1 [0, 3] 14 [9, 19] Year 219 [17, 21] 17 [15, 19] 3 [2, 4] 17 [15, 20] Year 318 [15, 20] 16 [15, 18] 0 [0, 1] 15 [11, 19] ComplexPlasticWoodStarter Hole Mounds Eggs / Chicks / Fledges Reproductive Success (% Fledglings from Eggs) Year13 19 / 1 / 0 0 % 3 20 / 8 / 2 10 % 0 0 / 0 / 0 0 % Year 24 27 / 8 / 2 7 % 8 47 / 18 / 8 17 % 0 0 / 0 / 0 0 % Year 34 0 / 0 / 2 0 % 5 0 / 0 / 10 0 % 0 0 / 0 / 0 0 % FUTURE CONSIDERATIONS FOR BURROWING OWL MITIGATION Location of mitigation site near extant populations of burrowing owls and fossorial mammals At least three to four burrows per owl individual / pair Armoring entrances in areas where coyotes are present Buried chicken wire along floors of boxes / tunnels to prevent filling by fossorial mammal digging Planting of low-lying vegetation on mounds with artificial burrows to 50-150 feet surrounding burrows Perches??? Monitoring!!! Plan for contingencies BURROWING OWL BREEDING ACTIVITY AT LONESTAR BURROWING OWL NUMBERS AND ACTIVITY AT LONESTAR ACKNOWLEDGEMENTS CALTRANS: Bruce April, Kim Smith, and Ted Thurston, the Office of Environmental Stewardship and Ecological Studies; SAN DIEGO ZOO INSTITUTE FOR CONSERVATION RESEARCH: Colleen Wisinski, Susanne Marczak, Lisa Nordstrom and the interns; Jeff Lincer; RECON: Meagan Olsen and Pete Tomsovic; TIERRA DATA: Jim Kellogg, James Lockman, and Fausto Larios; Jeff Kidd; Doug McKinney; AECOM: Scott McMillan, Lindsey Cavallero, and Linnea Spears-Lebrun