Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes
Endangered San Joaquin kit foxes (Vulpes macrotis mutica; SJKF) and California ground squirrels (Otospermophilus beecheyi; CAGS) occur sympatrically in many locations. CAGS can constitute a nuisance species and control strategies have included lethal measures administered within CAGS burrows. These...
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| Format: | Article |
| Language: | English |
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California Department of Fish and Wildlife
2023-12-01
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| Series: | California Fish and Wildlife Journal |
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| Online Access: | https://journal.wildlife.ca.gov/2023/12/29/comparison-of-san-joaquin-kit-fox-den-and-california-ground-squirrel-burrow-attributes/ |
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| author | Brian Cypher Alyse Gabaldon Francisco Ruiz Ponce Erica Kelly |
| author_facet | Brian Cypher Alyse Gabaldon Francisco Ruiz Ponce Erica Kelly |
| author_sort | Brian Cypher |
| collection | DOAJ |
| description | Endangered San Joaquin kit foxes (Vulpes macrotis mutica; SJKF) and California ground squirrels (Otospermophilus beecheyi; CAGS) occur sympatrically in many locations. CAGS can constitute a nuisance species and control strategies have included lethal measures administered within CAGS burrows. These measures could harm or kill a SJKF if mistakenly applied to an occupied SJKF den. To identify attributes to distinguish between SJKF dens and CAGS burrow, we assessed dimensions, penetration depths by 9.7-cm and 7.5-cm spheres, ejecta patterns, and the presence of various types of sign at 65 dens to which radiocollared SJKF were tracked and at 80 burrows that CAGS were observed to enter. Mean entrance height, width, and circumference all were significantly larger for SJKF den entrances. However, the ranges of values for all dimensions for the CAGS burrows completely encompassed the ranges for the SJKF dens. Penetration depths with the 7.5-cm sphere were similar for SJKF dens and CAGS burrows. The 9.7-cm sphere could not be inserted in over half of CAGS burrows and exceeded 1 m in depth in over half of the SJKF dens. Most SJKF dens had dirt berms but so did over half of the CAGS burrows. SJKF scats, prey remains, CAGS scats, and trash were observed at both SJKF dens and CAGS burrows although at different frequencies. CAGS tracks were only observed at seven CAGS burrows. None of the attributes we assessed provided unequivocal criteria for distinguishing between SJKF dens and CAGS burrows. Also, SJKF occasionally usurp CAGS burrows and CAGS occasionally move into vacant SJKF dens. Therefore, administering lethal control measures within burrows should be avoided as it presents too great a risk to SJKF as well as the many other species that also use CAGS burrows. |
| first_indexed | 2024-03-08T16:57:22Z |
| format | Article |
| id | doaj.art-ecf48e496e0a466580c3d0920040cabc |
| institution | Directory Open Access Journal |
| issn | 2689-419X 2689-4203 |
| language | English |
| last_indexed | 2024-03-08T16:57:22Z |
| publishDate | 2023-12-01 |
| publisher | California Department of Fish and Wildlife |
| record_format | Article |
| series | California Fish and Wildlife Journal |
| spelling | doaj.art-ecf48e496e0a466580c3d0920040cabc2024-01-04T22:51:03ZengCalifornia Department of Fish and WildlifeCalifornia Fish and Wildlife Journal2689-419X2689-42032023-12-01109410.51492/cfwj.109.17Comparison of San Joaquin kit fox den and California ground squirrel burrow attributesBrian Cypher0https://orcid.org/0000-0002-7349-545XAlyse Gabaldon1Francisco Ruiz Ponce2Erica Kelly3https://orcid.org/0000-0002-3033-1607California State University, Stanislaus, Endangered Species Recovery ProgramCalifornia State University, Stanislaus, Endangered Species Recovery ProgramCalifornia State University, Stanislaus, Endangered Species Recovery ProgramCalifornia State University, Stanislaus, Endangered Species Recovery ProgramEndangered San Joaquin kit foxes (Vulpes macrotis mutica; SJKF) and California ground squirrels (Otospermophilus beecheyi; CAGS) occur sympatrically in many locations. CAGS can constitute a nuisance species and control strategies have included lethal measures administered within CAGS burrows. These measures could harm or kill a SJKF if mistakenly applied to an occupied SJKF den. To identify attributes to distinguish between SJKF dens and CAGS burrow, we assessed dimensions, penetration depths by 9.7-cm and 7.5-cm spheres, ejecta patterns, and the presence of various types of sign at 65 dens to which radiocollared SJKF were tracked and at 80 burrows that CAGS were observed to enter. Mean entrance height, width, and circumference all were significantly larger for SJKF den entrances. However, the ranges of values for all dimensions for the CAGS burrows completely encompassed the ranges for the SJKF dens. Penetration depths with the 7.5-cm sphere were similar for SJKF dens and CAGS burrows. The 9.7-cm sphere could not be inserted in over half of CAGS burrows and exceeded 1 m in depth in over half of the SJKF dens. Most SJKF dens had dirt berms but so did over half of the CAGS burrows. SJKF scats, prey remains, CAGS scats, and trash were observed at both SJKF dens and CAGS burrows although at different frequencies. CAGS tracks were only observed at seven CAGS burrows. None of the attributes we assessed provided unequivocal criteria for distinguishing between SJKF dens and CAGS burrows. Also, SJKF occasionally usurp CAGS burrows and CAGS occasionally move into vacant SJKF dens. Therefore, administering lethal control measures within burrows should be avoided as it presents too great a risk to SJKF as well as the many other species that also use CAGS burrows.https://journal.wildlife.ca.gov/2023/12/29/comparison-of-san-joaquin-kit-fox-den-and-california-ground-squirrel-burrow-attributes/burrowscalifornia ground squirreldensotospermophilus beecheyisan joaquin kit foxvulpes macrotis mutica |
| spellingShingle | Brian Cypher Alyse Gabaldon Francisco Ruiz Ponce Erica Kelly Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes California Fish and Wildlife Journal burrows california ground squirrel dens otospermophilus beecheyi san joaquin kit fox vulpes macrotis mutica |
| title | Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes |
| title_full | Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes |
| title_fullStr | Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes |
| title_full_unstemmed | Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes |
| title_short | Comparison of San Joaquin kit fox den and California ground squirrel burrow attributes |
| title_sort | comparison of san joaquin kit fox den and california ground squirrel burrow attributes |
| topic | burrows california ground squirrel dens otospermophilus beecheyi san joaquin kit fox vulpes macrotis mutica |
| url | https://journal.wildlife.ca.gov/2023/12/29/comparison-of-san-joaquin-kit-fox-den-and-california-ground-squirrel-burrow-attributes/ |
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