Techniques for capturing bighorn sheep lambs
ABSTRACT Low lamb recruitment is a major challenge facing managers attempting to mitigate the decline of bighorn sheep (Ovis canadensis), and investigations into the underlying mechanisms are limited because of the inability to readily capture and monitor bighorn sheep lambs. We evaluated 4 capture...
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Wiley
2014-03-01
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| Series: | Wildlife Society Bulletin |
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| Online Access: | https://doi.org/10.1002/wsb.360 |
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| author | Joshua B. Smith Daniel P. Walsh Elise J. Goldstein Zachary D. Parsons Rebekah C. Karsch Julie R. Stiver James W. Cain Iii Kenneth J. Raedeke Jonathan A. Jenks |
| author_facet | Joshua B. Smith Daniel P. Walsh Elise J. Goldstein Zachary D. Parsons Rebekah C. Karsch Julie R. Stiver James W. Cain Iii Kenneth J. Raedeke Jonathan A. Jenks |
| author_sort | Joshua B. Smith |
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| description | ABSTRACT Low lamb recruitment is a major challenge facing managers attempting to mitigate the decline of bighorn sheep (Ovis canadensis), and investigations into the underlying mechanisms are limited because of the inability to readily capture and monitor bighorn sheep lambs. We evaluated 4 capture techniques for bighorn sheep lambs: 1) hand‐capture of lambs from radiocollared adult females fitted with vaginal implant transmitters (VITs), 2) hand‐capture of lambs of intensively monitored radiocollared adult females, 3) helicopter net‐gunning, and 4) hand‐capture of lambs from helicopters. During 2010–2012, we successfully captured 90% of lambs from females that retained VITs to ≤1 day of parturition, although we noted differences in capture rates between an area of high road density in the Black Hills (92–100%) of South Dakota, USA, and less accessible areas of New Mexico (71%), USA. Retention of VITs was 78% with pre‐partum expulsion the main cause of failure. We were less likely to capture lambs from females that expelled VITs ≥1 day of parturition (range = 80–83%) or females that were collared without VITs (range = 60–78%). We used helicopter net‐gunning at several sites in 1999, 2001–2002, and 2011, and it proved a useful technique; however, at one site, attempts to capture lambs led to lamb predation by golden eagles (Aquila chrysaetos). We attempted helicopter hand‐captures at one site in 1999, and they also were successful in certain circumstances and avoided risk of physical trauma from net‐gunning; however, application was limited. In areas of low accessibility or if personnel lack the ability to monitor females and/or VITs for extended periods, helicopter capture may provide a viable option for lamb capture. © 2013 The Wildlife Society. |
| format | Article |
| id | doaj-art-7aebda216b99449a8afec7eeda75612d |
| institution | DOAJ |
| issn | 2328-5540 |
| language | English |
| publishDate | 2014-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Wildlife Society Bulletin |
| spelling | doaj-art-7aebda216b99449a8afec7eeda75612d2025-08-20T02:49:19ZengWileyWildlife Society Bulletin2328-55402014-03-0138116517410.1002/wsb.360Techniques for capturing bighorn sheep lambsJoshua B. Smith0Daniel P. Walsh1Elise J. Goldstein2Zachary D. Parsons3Rebekah C. Karsch4Julie R. Stiver5James W. Cain Iii6Kenneth J. Raedeke7Jonathan A. Jenks8Department of Natural Resource ManagementSouth Dakota State UniversityBrookingsSD57007USAColorado Parks and Wildlife317W Prospect RoadFort CollinsCO80526USACollege of Forest ResourcesUniversity of WashingtonSeattleWA98195USADepartment of Ecosystem and Conservation SciencesUniversity of MontanaMissoulaMT59812USADepartment of Fish, Wildlife, and Conservation EcologyNew Mexico State UniversityLas CrucesNM88003USAColorado Parks and Wildlife4255 Sinton RoadColorado SpringsCO80907USAUnited States Geological Survey, New Mexico Cooperative Fish and Wildlife Research Unit, Department of Fish, Wildlife, and Conservation EcologyNew Mexico State UniversityLas CrucesNM88003USACollege of Forest ResourcesUniversity of WashingtonSeattleWA98195USADepartment of Natural Resource ManagementSouth Dakota State UniversityBrookingsSD57007USAABSTRACT Low lamb recruitment is a major challenge facing managers attempting to mitigate the decline of bighorn sheep (Ovis canadensis), and investigations into the underlying mechanisms are limited because of the inability to readily capture and monitor bighorn sheep lambs. We evaluated 4 capture techniques for bighorn sheep lambs: 1) hand‐capture of lambs from radiocollared adult females fitted with vaginal implant transmitters (VITs), 2) hand‐capture of lambs of intensively monitored radiocollared adult females, 3) helicopter net‐gunning, and 4) hand‐capture of lambs from helicopters. During 2010–2012, we successfully captured 90% of lambs from females that retained VITs to ≤1 day of parturition, although we noted differences in capture rates between an area of high road density in the Black Hills (92–100%) of South Dakota, USA, and less accessible areas of New Mexico (71%), USA. Retention of VITs was 78% with pre‐partum expulsion the main cause of failure. We were less likely to capture lambs from females that expelled VITs ≥1 day of parturition (range = 80–83%) or females that were collared without VITs (range = 60–78%). We used helicopter net‐gunning at several sites in 1999, 2001–2002, and 2011, and it proved a useful technique; however, at one site, attempts to capture lambs led to lamb predation by golden eagles (Aquila chrysaetos). We attempted helicopter hand‐captures at one site in 1999, and they also were successful in certain circumstances and avoided risk of physical trauma from net‐gunning; however, application was limited. In areas of low accessibility or if personnel lack the ability to monitor females and/or VITs for extended periods, helicopter capture may provide a viable option for lamb capture. © 2013 The Wildlife Society.https://doi.org/10.1002/wsb.360bighorn sheepcapturehelicopterlambsneonatesnetgun |
| spellingShingle | Joshua B. Smith Daniel P. Walsh Elise J. Goldstein Zachary D. Parsons Rebekah C. Karsch Julie R. Stiver James W. Cain Iii Kenneth J. Raedeke Jonathan A. Jenks Techniques for capturing bighorn sheep lambs Wildlife Society Bulletin bighorn sheep capture helicopter lambs neonates netgun |
| title | Techniques for capturing bighorn sheep lambs |
| title_full | Techniques for capturing bighorn sheep lambs |
| title_fullStr | Techniques for capturing bighorn sheep lambs |
| title_full_unstemmed | Techniques for capturing bighorn sheep lambs |
| title_short | Techniques for capturing bighorn sheep lambs |
| title_sort | techniques for capturing bighorn sheep lambs |
| topic | bighorn sheep capture helicopter lambs neonates netgun |
| url | https://doi.org/10.1002/wsb.360 |
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