Stillwater PGM-Cu Project Whip-poor-will and Common Nighthawk Survey 2013

Transcription

1 Stillwater PGM-Cu Project Whip-poor-will and Common Nighthawk Survey 2013 August 2013 Prepared for: Stillwater Canada Inc. Prepared by: Allan G. Harris Robert F. Foster

2 Table of Contents Table of Contents... i List of Figures... i List of Tables... i Introduction... 2 Methods... 2 Results and Discussion... 4 Literature Cited... 5 List of Figures Figure 1. Stillwater Project showing Whip-poor-will and Common Nighthawk survey locations List of Tables Table 1. Conditions for Whip-poor-will survey May (start/end) Table 3. Sound recordings analysed for each recorder Table 2. Whip-poor-will and Common Nighthawk survey results May Stillwater Project Northern Bioscience i

3 Introduction This report summarizes the results of surveys for Whip poor will (Caprimulgus vociferous) and Common Nighthawk (Chordeiles minor) at the Stillwater Project site on May and sound recorder data. Although surveys were completed in June 2011, this survey was conducted to provide additional data on the status of these species at the Stillwater Project site, including areas that were not road accessible. Methods A survey for Whip-poor-will, Common Nighthawk, and other nocturnal birds was conducted on May 28, 2013 along the main north-south access road through the study area (Figure 1). Weather conditions were conducive for the survey (Table 1). Although there was intermittent light drizzle, moths, caddisflies and other flying insects were active. The survey locations were chosen to maximize the distribution across the study area, while maintaining a spacing of at least approximately 1 km to reduce the chance of hearing Whippoor-wills from more than one station. In accordance with Ontario s Whip Poor Will Roadside Survey Participant s Guide (BSC, 2013), surveys were timed to coincide with at least 50% moon exceedance. Full moon occurred on May 24, Whip-poor-will surveys consisted of 3 minute point counts beginning at least 30 minutes after sunset. Ten stations were surveyed between 21:00 and 22:00 to cover the dusk period when Common Nighthawks are most active. Survey conditions are summarized in Table 1. Table 1. Conditions for the Whip-poor-will and Common NIghthawk survey May (start/end). Date Conditions Sunset Time 21:36 Moonrise Time 00:18 Temperature ( o C) 11 / 10 Wind (Beaufort Scale) 1 / 0 Precipitation Intermittent light drizzle (3 stations) Sky Overcast Sound recorders (Wildlife Acoustics SM2 with stereo microphones) were deployed at four locations in potential Whip-poor-will and Common Nighthawk habitat (rock barren and open Jack Pine stands) from May 29 until mid to late June (depending on the recorder) (Figure 1). Recorders were deployed by helicopter and therefore restricted to sites open enough for the helicopter to land. Nevertheless, these sites appeared to be the most suitable habitat in the LSA for Common Nighthawk and Whip-poor-will based on the mix of open habitat and adjacent forest. Northern Bioscience 2

4 Recordings from at least two dates from each recorder dates were analysed for Whip-poor-will and Common Nighthawk calls. Two 10-minute sections of the recording were listened to: one at 30 minutes after sunset (corresponding to peak Common Nighthawk activity) and one about an hour after sunset (when Whip-poor-wills are typically active). A visual scan of the remainder of the sonogram was also completed. Due to wind noise, recorder failure, and limited data card capacity, the dates analysed differed between recorders (Table 2). Table 2. Sound recordings analysed for each recorder. Recorder May 29 May 30 June 17 June 21 June 22 June 23 1 Yes Yes Yes Yes Yes 2 Yes Yes Yes Yes Yes 3 Yes Yes 4 Yes Yes Yes Yes Figure 1. Stillwater Project showing Whip-poor-will and Common Nighthawk survey locations. Refer to Table 3 for details. Northern Bioscience 3

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6 Results and Discussion Despite suitable timing and conditions, no Whip-poor-wills or Common Nighthawks were detected during field surveys or on sound recordings, nor were any incidental observations of these species made along the roads while travelling between stations. Sound recorders detected Spring Peepers and White throated Sparrows most nights at all stations as well as Swainson s Thrush, Hermit Thrush and Winter Wren, indicating suitable conditions for auditory surveys for Common Nighthawks and Whip-poor-wills. IR requested justification of the methodology used to confirm the absence of Common Nighthawks and Whip-poor-wills. Auditory surveys are the generally accepted protocol for surveying for these species given their crepuscular and nocturnal behaviour. Nests of these species consist of a shallow scrape on the forest floor and are very difficult to find. Surveys in 2011 and 2013 along the road corridor and sound recordings on multiple dates throughout the breeding season suggest that these areas are not regularly used for breeding by these species. Common Nighthawks are common and widespread north of Lake Superior (Sandilands 2007) and use of the LSA cannot be ruled out. Whip-poor-wills are confined to isolated occurrences north of Lake Superior (Mills 2007), and appear unlikely to be regularly using the LSA based on our surveys and known distribution. Table 3. Whip-poor-will and Common Nighthawk survey results May Stillwater Project. Refer to Figure 1 for locations. Station Time 1 st Survey Time 2nd Survey Target Species Easting Northing Comments 1 21:00 23:30 Both Gravel pit; Light drizzle (2 nd ) 2 21:08 23:25 Both Gravel pit; Light drizzle (2 nd ) 3 21:13 23:20 Both Light drizzle (2 nd ) 4 21:18 23:25 Both Gravel pit; Light drizzle (2 nd ) 5 21:26 23:09 Both Light drizzle (1 st ) 6 21:32 23:01 Both :38 22:56 Both Light drizzle (2 nd ) 8 21:45 22:48 Both :52 22:34 Both Light drizzle (2 nd ) 10 21:59 22:06 Both Light drizzle (2 nd ) 11-22:06 WHIP :11 WHIP :17 WHIP Recorder Recorder Recorder Recorder Northern Bioscience 5

7 Literature Cited Bird Studies Canada (BSC) Whip-poor-will Roadside Survey Participant s Guide. /wpwi/2013_ Roadside_Survey_Guide_2013_revised.pdf Mills, A Whip-poor-will. pp In Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage, and A.R. Coutourier. Atlas of Breeding Birds of Ontario, Bird Studies Canada, Environment Canada, Ontario Ministry of Natural Resources, and Ontario Nature. Toronto. Sandilands, A Common Nighthawk. pp In Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage, and A.R. Coutourier. Atlas of Breeding Birds of Ontario, Bird Studies Canada, Environment Canada, Ontario Ministry of Natural Resources, and Ontario Nature. Toronto. Northern Bioscience 6