Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory on Vancouver Island - 2007 Photo by Jared Hobbs BC Conservation Corps Vancouver Island Species at Risk 2008 Prepared for: Sean Pendergast, BC Ministry of Environment Prepared by: Vicky Young, Matt Dil, Jeannine Randall and Nigel Jackett Funding Provided by: BC Conservation Corps October 2008 Project Completion Report for the BCCC 2008 Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory Abstract This report summarizes the Vancouver Island Northern Pygmy-owl (Glaucidium gnoma swarthi) inventory conducted by the BC Conservation Corps Vancouver Island Species at Risk crew for the BC Ministry of Environment during 2008. The majority of survey effort was focused on northern and central Vancouver Island. From the period of May 15 to July 16, 2008, 428 call playback stations were conducted for G. g. swarthi. A total of 51 owls were detected; 48 of which were G. g. swarthi. The 2008 inventory primarily targeted previous detection sites to verify the repeat presence of G. g. swarthi. Areas of suitable habitat were also surveyed to further determine the distribution of G. g. swarthi on Vancouver Island. This new data will help direct future inventory efforts for G. g. swarthi as well as indicate potential Wildlife Habitat Areas (WHAs) under the Identified Wildlife Management Strategy (IWMS) Forest and Range Practices Act. Acknowledgments I would like to thank the BC Conservation Corps Vancouver Island Species at Risk Crew – Nigel Jackett, Jeannine Randall and Matt Dil. We worked as a team to conduct these surveys which would not have been as successful without their dedication and hard work. Thank you to Ministry of Environment biologists Sean Pendergast and Jared Hobbs for providing historical data, maps and guidance; the BC Conservation Corps for providing funding; and the BC Conservation Foundation for providing administrative support. Additional funding for the project was provided by: TimberWest Forest Corp, Ministry of Transport, BCTS and the Ministry of Environment - Conservation Framework. ii Project Completion Report for the BCCC 2008 Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory Table of Contents Abstract............................................................................................................................... ii Acknowledgments............................................................................................................... ii Table of Contents...............................................................................................................iii List of Figures....................................................................................................................iii List of Tables .....................................................................................................................iii Introduction......................................................................................................................... 1 Species ............................................................................................................................ 1 Study Area ...................................................................................................................... 1 Surveys............................................................................................................................ 3 Methods............................................................................................................................... 3 Results................................................................................................................................. 6 Conclusion and Recommendations..................................................................................... 7 References......................................................................................................................... 10 Appendix 1: Owl Survey Form – Owl Site Description................................................... 12 Appendix 2: Owl Survey Form – Owl Survey Form........................................................ 13 Appendix 3: Owl Survey Form – Owl Detection Form.................................................... 14 List of Figures Figure 1. Map of Vancouver Island Northern Pygmy Owl (Glaucidium gnoma swarthi) call-playback stations throughout central and northern Vancouver Island......................... 2 Figure 2. Map of Vancouver Island Northern Pygmy Owl (Glaucidium gnoma swarthi) call-playback stations in the Nahmint Valley on Vancouver Island................................... 3 Figure 3. Glaucidium gnoma swarthi detections (in red) from call-playback surveys conducted on central and northern Vancouver Island in 2008. .......................................... 6 Figure 4. Glaucidium gnoma swarthi detections (in red) from call-playback surveys conducted in the Nahmint Valley on Vancouver Island in 2008........................................ 7 List of Tables Table 1 Number of transects, stations, owl detections and total listening time for the 2008 G. g. swarthi call-playback surveys.................................................................................... 6 Table 2 Number of owl species detected and their relative percentages for the 2008 G. g. swarthi call-playback surveys............................................................................................. 7 iii Project Completion Report for the BCCC 2008 Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory Introduction Species The Northern Pygmy-Owl (Glaucidium gnoma) is a small woodland diurnal owl most active during dawn and dusk (Lewis 2008). It is a year-round resident of western North American forests ranging from British Columbia to Mexico (Darling 2003). The Vancouver Island subspecies, Glaucidium gnoma swarthi, is believed to be endemic to Vancouver Island and adjacent islands (Cooper and Beauchesne 2004). This subspecies is provincially Blue-listed by the Conservation Data Centre (BC Conservation Data Centre 2008) and managed through the Ministry of Environment’s Identified Wildlife Management Strategy (IWMS) under the Forest and Range Practices Act. In general Northern Pygmy-Owls have been reported breeding in mature and second-growth coniferous forests, mixed riparian forest, and pure deciduous stands (Cooper and Beauchesne 2004). They are usually associated with forest edge habitats rather that continuous forest (Campbell et al. 1990; Holt and Petersen 2000; Darling 2003). These secondary cavity-nesters rely particularly on cavities excavated by Northern Flickers (Colaptes auratus) and Hairy Woodpeckers (Picoides villosus) (Cooper and Beauchesne 2004). There is little known however about the habitat requirements of the Vancouver Island Northern Pygmy-Owl (hereafter referred to as G. g. swarthi). Study Area Surveys were conducted throughout Vancouver Island (Figures 1 and 2) and targeted historical detections from previous inventories. These included owl surveys conducted in the Campbell River Watershed through BC Hydro’s Bridge Coastal Fish & Wildlife Restoration Program and in the Nimpkish Valley – TFL # 37 for CanFor (now Western Forest Products). Additional surveys were conducted in the following areas: Memekay River, White River, Stewart Lake, McCreight Lake, Nahmint River. These areas did not have previously mapped detection sites but contained a mosaic of mature forest, clear cuts and riparian areas. These are habitat attributes commonly selected for by Northern Pygmy-Owls in other regions of the province. 1 Project Completion Report for the BCCC 2008 Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory Figure 1. Map of Vancouver Island Northern Pygmy Owl (Glaucidium gnoma swarthi) call-playback stations throughout central and northern Vancouver Island. 2 Project Completion Report for the BCCC 2008 Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory Figure 2. Map of Vancouver Island Northern Pygmy Owl (Glaucidium gnoma swarthi) call-playback stations in the Nahmint Valley on Vancouver Island Surveys The BC Conservation Corps (BCCC) Vancouver Island Species at Risk crew was tasked with conducting Northern Pygmy-owl surveys during the 2008 field season. Call- playback surveys were used to determine presence/not detected of G. g. swarthi. This listed species is managed under the Forest and Range Practices Act - Identified Wildlife Management Strategy (IWMS). Survey results could help guide management decisions concerning the species and further clarify its distribution and habitat requirements on Vancouver Island. Methods Surveys were designed and implemented based on provincial owl and raptor survey standards where possible (Hausleitner 2006, RISC 2001). The methodology regarding 3 Project Completion Report for the BCCC 2008 Northern Pygmy-Owl (Glaucidium gnoma swarthi) Inventory distance between stations and the timing of the surveys was based on previous Northern Pygmy-Owl inventories conducted on Vancouver Island (Menzies and Tripp 2007). Surveys were not conducted during inclement weather of high winds or steady rain. Surveys were continued if inclement weather stopped or improved. Due to timing restrictions these surveys included only one repetition and were not conducted during the breeding period for G. g. swarthi on Vancouver Island. Spot check stations were used to target historical Northern Pygmy-Owl detections. In areas with no prior detections transects were strategically placed to target habitats consisting of a mosaic of clear-cut and mature