Monitoring Forest Owls in TFL 37, Northern Vancouver Island: Phase II REPORT

Transcription

1 Monitoring Forest Owls in TFL 37, Northern Vancouver Island: 2003 Phase II REPORT Prepared for: John A. Deal, RPBio, RPF, Ecosystem Management Forester Canadian Forest Products Ltd. Coastal Operations - Englewood Woss, B.C. V0N 3P0 Prepared by: Wayne R. Matkoski, RPBio & Andrew T. Smith W.R.M. Resource Consulting Ltd Hector Road Comox, B.C. V9M 3Y7 April 2003

2 EXECUTIVE SUMMARY From March 10 to April 2, 2003, Phase II of the Nimpkish Owl Survey was conducted on TFL 37 on northern Vancouver Island by WRM Resource Consulting, Ltd. for Canadian Forest Products Ltd. Coastal Operations Englewood (Canfor). The 2003 owl inventory was part of Canfor s ongoing commitment to monitoring to determine the effectiveness of ecosystem-based management. Canfor began long-term monitoring of owls in 2002 (AXYS, 2003), but had completed previous owl inventories on TFL 37 in 1993, 1995, 1996 and 1997 (AXYS, 1998; Deal and Lamont, 1996; Matkoski, 1997). The 2002 and 2003 owl surveys were designed to fulfill the requirements of two different studies: the BC Nocturnal Owl Survey and Canfor s Nimpkish Owl Survey, which targeted northern pygmy-owls (Glaucidium gnoma swarthi). The swarthi subspecies of the northern pygmy-owl occurs only on Vancouver Island (Fraser et al., 1999) and is blue-listed in B.C. as vulnerable, or particularly sensitive to human activities or natural events (Fraser et al., 1999). Surveys were split into two phases for 2003 to accomplish different priorities. Phase I satisfied BC Nocturnal Owl Survey requirements and Canfor s northern pygmy-owl survey objectives. Phase II targeted all five owl species known to occur in the Nimpkish Valley: northern pygmy-owl; northern saw-whet owl (Aegolius acadicus); western screech-owl (Otus kennicottii kennicottii); barred owl (Strix varia); and great horned owl (Bubo virginianus). All five species, with the exception of the northern pygmy-owl, are yellow-listed in B.C. according to the Conservation Data Centre (2003) and the populations are therefore considered to be secure and not at risk of extinction. The objective of Phase II was to collect information about these four additional species that was not collected during Phase I. Phase I was funded by the Forest Investment Account (FIA), while Phase II was funded by Canfor. Results of both Phase I and Phase II will be used by Canfor for owl management strategies and presence/absence monitoring. Both phases were based on a series of ten road transects with ten points each, placed 1.6 km apart, for a total length of 14.4 km for each transect. During Phase I, surveyors listened for voluntary calls for two minutes, then played a series of three northern pygmy owl recordings on a portable tape deck, with 30 seconds of silence in between, followed by a further five minutes of listening after all three pygmy owl calls were broadcast. Phase I consisted of two passes of each transect, both completed in February. Phase II utilised use the same transects and similar methodology to the pygmy owl tape broadcast, but included call playback for the four additional species listed above. The B.C. Nocturnal Owl Survey (BCNOS) was started in BC in 2000 by Dick Cannings of Bird Studies Canada with the intention of long-term monitoring of owl populations and distributions throughout B.C. The BCNOS methodology consists of listening for voluntary calls for two minutes at each station, and recording the species, location and time of each owl detection (Cannings, 2002). Owls detected during the first two minutes of the surveys only will be used as data for the BCNOS. The BCNOS specifies that surveys should be conducted once in February and, if possible, once in January or March. Data gathered during both phases of the project can be used for BCNOS; therefore, the results from the first pass of Phase I, as well as Phase II, will be provided to the BCNOS. Ten owls in total were detected at the 200 points surveyed during Phase I, including two northern pygmy-owls, seven western screech-owls and one great horned owl. Four of these detections were voluntary (i.e. calls were heard before call playback), and six were responses to tape playback. Seventeen owls were detected at the 100 points surveyed during Phase II, including two northern pygmy-owls, one northern saw-whet owl, 12 western screech-owls, one barred owl and one great horned owl. None of these detections were voluntary (all 17 responded to tape playback). WRM Resource Consulting, Ltd. March 2003 i

3 ACKNOWLEDGEMENTS We would like to thank John Deal, Ecosystem Management Forester, for Canadian Forest Products Ltd. at Canfor s Englewood Logging Division, for his dedication towards implementing and continuing studies such as the Nimpkish Owl Inventory, as well as his guidance and assistance through all phases of the survey. We would also like to thank Canadian Forest Products Ltd. and Forest Investment Account for their financial support and providing the opportunity to conduct the Nimpkish Owl Survey. WM AS WRM Resource Consulting, Ltd. March 2003 ii

4 TABLE OF CONTENTS EXECUTIVE SUMMARY...i ACKNOWLEDGEMENTS...ii LIST OF TABLES...iv INTRODUCTION... 1 OBJECTIVES... 2 STUDY AREA... 3 METHODS... 3 RESULTS... 6 CONCLUSIONS... 8 DISCUSSION AND RECOMMENDATIONS... 8 LITERATURE CITED APPENDIX I WRM Resource Consulting, Ltd. March 2003 iii

5 LIST OF TABLES Table 1. Summary of Nimpkish Owl Survey dates and starting times Table 2. Owl species surveyed during the 2003 Nimpkish Owl Survey and owl status in the Nimpkish Valley... 7 Table 3. Summary of Phase I 2003 Nimpkish Owl Survey detections... 7 Table 4. Summary of Phase II 2003 Nimpkish Owl Survey detections 7 WRM Resource Consulting, Ltd. March 2003 iv

6 INTRODUCTION Raptors, or birds of prey, are considered an indicator of environmental pollution and habitat destruction or degradation because they are relatively long-lived and feed high on the food chain (Resource Inventory Committee (RIC), 2001, now known as the Resource Information Standards Committee). Because of their close link to mature and overmature forests for nesting habitat, some owl species have been used as indicators of ecosystem health throughout the world (Deal and Lamont, 1996). Certain owl species are secondary-cavity nesters since they nest in cavities in trees created either naturally or by woodpeckers. Four of the five owl species being surveyed in the Nimpkish Owl Inventory are secondary-cavity nesters, including the northern pygmy-owl (Glaucidium gnoma swarthi), the northern saw-whet owl (Aegolius acadicus), the western screech-owl (Otus kennicottii kennicottii) and the barred owl (Strix varia). The northern pygmyowl is blue-listed by the B.C. Ministry of Water, Land and Air Protection as a result of this habitat association (Fraser et al., 1999). The swarthi subspecies of the northern pygmy-owl occurs only on Vancouver Island and is listed as vulnerable, or particularly sensitive to human activities or natural events (Fraser et al., 1999). The Survey Methods for Raptors in B.C. (RIC, 2001) noted coniferous forests as suitable or preferred habitat for all five owl species surveyed in Tree Farm Licence (TFL) 37. Most forested areas, such as that found in TFL 37, are made up of combinations of old-growth and secondgrowth forests with coniferous and deciduous trees. The Resource Inventory Committee (2001) stated it is evident that raptors are negatively affected by human activities because of the disproportionately high number of raptors on the red and blue lists in B.C. The committee further stated that raptors could also be positively influenced by certain human activities and management actions. To be able to effectively manage and understand owl populations, information is needed on owl habitat use. Inventory and monitoring of owl populations is important for comparing present owl status with the past and future. It is also necessary for informed land use decisions and better management. The distribution and relative abundance of owls on northern Vancouver Island is largely unknown because of the lack of inventory and research data, as well as the difficulty in surveying owls. Fuller and Mosher (1981) noted that owls are difficult to detect because of their low densities, nocturnal behaviour and rapid movement over large areas. The Resource Inventory Committee (2001) categorized owls as inconspicuous raptors because they have concealed nest sites, nocturnal lifestyles, and secretive hunting styles. Surveying for inconspicuous raptors such as owls requires surveyors to search using broadcast calls (call playback from a portable tape player) and listening for replies and/or visually detecting WRM Resource Consulting, Ltd. March

7 the owls. Raptors call to identify themselves, establish and defend territories, and to attract mates. The use of call playbacks takes advantage of this by putting an intruder into an already claimed territory (Smith, 1975). From February 10 to February 25, 2003, Phase I of the Nimpkish Owl Inventory was conducted on TFL 37 in the Nimpkish Valley on northern Vancouver Island. The objective of Phase I of the 2003 Nimpkish Owl Survey was to inventory northern pygmy-owls (the targeted species), northern saw-whet owls, western screech-owls, barred owls and great horned owls (incidental species) on TFL 37, map the location of their detections, and meet the survey requirements of BC Nocturnal Owl Survey. Phase II of the Nimpkish Owl Inventory was conducted on TFL 37 from March 10 to April 2, The objective of Phase II of the 2003 Nimpkish Owl Survey was to inventory all five of the owl species (listed above) on TFL 37, map the location of their detections, and meet the survey requirements of BC Nocturnal Owl Survey. The 2003 Nimpkish Owl Survey was the second year of an ongoing monitoring program designed to monitor owl populations and locations. The 2003 Nimpkish Owl Survey resulted in 27 owl detections, including four northern pygmy-owls (two during Phase I plus two during Phase II), one northern saw-whet owl (Phase II), 19 western screech-owls (seven plus 12), one barred owl (Phase II) and two great horned owls (one plus one). OBJECTIVES The 2003 Nimpkish owl survey was part of an ongoing commitment to monitor the effectiveness of ecosystem-based management practised by Canfor. Canfor has been monitoring owl presence / absence on TFL 37 since Continued surveys help to allow an understanding of the effect of these practices on wildlife species and also help to shape future management practices. Critical to this process is the monitoring of species that are considered to be at risk, such as the northern pygmy-owl. Canfor has also made a commitment to the BC Nocturnal Owl Survey (BCNOS) to continue surveying owl populations in the TFL to aid in their efforts to monitor owl populations throughout B.C. These objectives will be satisfied in two phases in Phase I involved a two minute voluntary response period at the beginning of each survey station followed by northern pygmy-owl (NPOW) tape playbacks. This phase satisfied the commitment to the BCNOS, which specifies the two minute voluntary response period only, while the NPOW playbacks satisfied monitoring of the northern pygmy-owl. WRM Resource Consulting, Ltd. March

8 Phase II included the above components but also incorporated tape playbacks for four additional species: northern saw-whet owl; western screech-owl; barred owl; and great horned owl. This phase will satisfy the ongoing commitment to monitor wildlife populations on TFL 37 and will allow a comparison with previous surveys that included all five owl species. STUDY AREA The 2003 Nimpkish Owl Survey was completed on Canadian Forest Products Ltd. s (Canfor) TFL 37. Located on northern Vancouver Island, TFL 37 totals approximately 189,000 ha in size and encompasses most of the Nimpkish River watershed. The Biogeoclimatic zones/subzones/variants represented in TFL 37 are CWHxm2, CWHmm1, CWHvm1, CWHvm2, MHmm1, MHmmp and ATc. The topography and landforms in TFL 37 are typical of the insular mountains physiographic region. Elevations range from sea level to 1,800 m in TFL 37. Canfor s divisional office is located in the town of Woss, at latitude and longitude (See Appendix I for a map of the study area.) Ten owl transects, each consisting of ten survey points located 1.6 km apart, are located throughout TFL 37. The transects are located along main or secondary logging roads. METHODS The 2003 Nimpkish Owl Survey followed both the Resource Inventory Standards Committee (RISC, formerly known as the Resource Inventory Committee (RIC)) standards for raptor surveys (2001) and the BC Nocturnal Owl Survey (BCNOS) guidelines (Cannings, 2002). As recommended by the BCNOS, survey stations were located on 14.4 km long road transects with stations placed 1.6 km apart to maximize survey coverage (and to minimize broadcasting the taped owl calls into adjacent owl territories if tape playbacks were to be employed). Thus, there were ten stations per transect. Ten transects were set up throughout TFL 37, therefore totalling 100 survey points. Each survey point was visited a total of three times during the months of February, March and April in the 2003 Nimpkish Owl Survey. The first two surveys were completed under Phase I of the Nimpkish Owl Survey while the final pass was completed under Phase II. The transects are each assigned a unique name and each have their points permanently numbered from 1 to 10 to assist in record keeping and data control. During Phase I, each of the transects were surveyed twice. The starting point for the second pass was the opposite end of the starting point for the first pass. For example, if the Vernon Lake transect was surveyed on the first pass beginning at the southern end, then the second pass would begin at the northern end of WRM Resource Consulting, Ltd. March

9 the transect. Survey start times were also varied as much as possible in an attempt to allow survey points to be visited at different times of the evening. See Table 1 for start times. When an owl was detected while surveying, no more taped calls were broadcast except when necessary to positively identify an owl. Surveying was halted to minimize the risk of nest or territory abandonment by frightening the owl (Deal and Lamont, 1996). The Resource Inventory Committee (2001) also states that taking the time to respond to taped calls may alter the time budget of the bird, which may interfere with critical breeding behaviour such as feeding, courtship or mating. Table 1. Summary of Nimpkish Owl Survey dates and starting times. TRANSECT SURVEY # DATE START STN # START TIME OWL(S) DETECTED Mt Cain 1 10-Feb 1 18:08 N Lukwa 1 10-Feb 1 20:50 N Woss Lake 1 10-Feb 1 23:00 N Oktwanch 1 11-Feb 1 17:46 Y (1) Sebalhall 1 11-Feb 10 19:40 Y (1) Vernon Lake 1 11-Feb 1 21:54 Y (1) Noomas 1 12-Feb 10 18:35 Y (1) Iron Mine 1 12-Feb 1 21:12 N Huson 1 17-Feb 1 19:33 N Klak Lake 1 17-Feb 1 22:13 Y (1) Lukwa 2 19-Feb 10 18:27 N Mt Cain 2 19-Feb 10 21:43 N Vernon Lake 2 20-Feb 10 19:02 Y (1) Woss Lake 2 21-Feb 10 19:18 N Sebalhall 2 24-Feb 1 19:04 N Oktwanch 2 24-Feb 10 21:33 Y (1) Noomas 2 25-Feb 1 19:05 Y (1) Huson 2 25-Feb 10 22:07 N Iron Mine 2 24-Feb 10 21:15 Y (1) Klak Lake 2 25-Feb 10 21:05 Y (1) Lukwa 3 10-Mar 1 20:40 N Mt Cain 3 10-Mar 1 19:30 Y (1) Vernon Lake 3 11-Mar 1 19:40 Y (3) Woss Lake 3 25-Mar 1 19:20 Y (1) Sebalhall 3 01-Apr 1 19:43 Y (2) Oktwanch 3 17-Mar 1 19:52 Y (3) Noomas 3 02-Apr 10 19:18 Y (2) Huson 3 27-Mar 1 20:22 Y (1) Iron Mine 3 25-Mar 1 19:46 Y (3) Klak Lake 3 11-Mar 1 19:00 Y (1) WRM Resource Consulting, Ltd. March

10 The 2003 BCNOS targeted the following five owl species that are known to inhabit TFL 37: northern pygmy-owl (NPOW), northern saw-whet owl (NSOW), western screech-owl (WSOW), barred owl (BAOW) and great horned owl (GHOW). The Nimpkish Owl Survey component was designed to target the northern pygmy-owls by playing taped NPOW calls at each survey point after the BCNOS component (two minutes of silent listening) was completed. Phase I of the survey was conducted on weeknights from February 10 to February 25, Owl surveying began about one-half to one hour after sunset and typically ended at approximately 00:30 PDT. During periods of adverse weather, such as moderate winds (estimated at 20 km/h or greater, which is a Beaufort 4 rating) or during periods of steady rain, owl surveys were not conducted. This followed the weather guidelines as outlined in the Resource Inventory Committee standard (2001). (Note: There were isolated instances when surveys were conducted during adverse weather conditions if it was determined to be necessary to complete the survey.) Pre-recorded NPOW owl calls, from the Peterson Western Bird Calls CD series, were broadcast at each survey point using portable cassette players. The recordings on the cassette tapes were set up so that a series of NPOW calls was recorded three successive times. Each series of calls lasted approximately 25 seconds. There were approximately 15 individual calls during each NPOW series. Phase II of the survey was conducted on weeknights from March 10 to April 2, The survey methodology used during Phase II was similar to Phase I, except that all five of the owl species calls were played after the initial two minute listening period. The owl call recordings on the cassette tapes are organised so that a set of each owl species calls were recorded three successive times (three sets of calls equals one series). The order on the tape is from smallest owl species to largest. The tapes, therefore, consist of one series of three sets of calls for each species in the following order: NPOW; NSOW; WSOW; BAOW; and GHOW. Each recording lasts from 20 to 30 seconds. There was a 30 second listening period after each of the first two sets of calls was broadcast, then a five minute listening period after the third set of each owl species. For each species, then, we have the following progression: set one (~25 sec.); wait 30 sec.; set two (~25 sec.); wait 30 sec.; set three (~25 sec.); wait five minutes. This makes for a total of approximately seven and a half minutes for each owl species and a total of 40 minutes (including the initial two minutes voluntary time) for an entire survey of all five species at each survey station. Note that while surveys attempt to keep the timing as close as possible to the stated methodology, it is often necessary to wait slightly longer than prescribed to determine whether an owl may been detected or not, especially during periods of inclement weather or at noisy stations. The total time spent at each station is, therefore, often slightly longer than 40 minutes. WRM Resource Consulting, Ltd. March

11 When surveying for owls, the cassette players were held at chest level to maintain a consistent surveying height. The tape player was shifted 120 o for each series of calls as per the Resource Inventory Committee standard (2001). At each survey point, the three series of NPOW calls were broadcast. After each call series was broadcast, the tape players were turned off and surveyors listened/looked for responses for 30 seconds. When an owl was detected while surveying, no more taped calls were broadcast except when necessary to positively identify an owl. Surveying was halted to minimize the risk of nest or territory abandonment by frightening the owl (Deal and Lamont 1995). The Resource Inventory Committee (2001) also stated that taking the time to respond to taped calls may alter the time budget of the bird, which may interfere with critical breeding behaviour (feeding, courtship, mating). The tape broadcast period was preceded by a two minute silent listening period (to listen for voluntary owl vocalisations and meet the requirements of the BCNOS) and followed up with a five minute silent interval after each series of calls to listen for owls that may be responding to the taped calls (to meet the requirements of the RIC standard). Owl locations were determined by estimating distances and taking a compass bearing with a hand-held compass, or by triangulation. In cases where an owl changed locations, the place it was first heard or seen was noted, then comments made about its moving behaviour. Temperature, cloud cover, rain, snow and wind levels were noted at each transect, as per the BCNOS standard. Survey start and end times, as well as the time of each owl detection, were also noted. RESULTS One hundred survey points were each surveyed twice during Phase I of the Nimpkish Owl Survey in 2003, resulting in ten owl detections (Table 2). It is important to note that the ten detections may not represent ten individual owls. Since each survey point was visited twice, it is possible the same owl may have been detected at either successive surveys at the same point or at adjacent points. Phase II had 100 survey points surveyed one time resulted in 17 owl detections. Table 3 details the Phase I owl detections, Table 4 shows the Phase II detections. WRM Resource Consulting, Ltd. March

12 Table 2. Owl species surveyed during the 2003 Nimpkish Owl Survey and owl status in the Nimpkish Valley. SPECIES # OF DETECTIONS # OF DETECTIONS PERIOD OF ACTIVITY BREEDING CONFIRMATION 1 Phase I Phase II NPOW 2 2 Diurnal & Nocturnal Probable NSWO 0 1 Nocturnal Probable WSOW 7 12 Nocturnal Confirmed June 10, 1992 BAOW 0 1 Diurnal & Nocturnal Confirmed July 20, 1992 GHOW 1 1 Nocturnal Unconfirmed 1 Lessard (1995); Campbell et al. (1990) Table 3. Summary of Phase I 2003 Nimpkish Owl Survey detections. DATE SPECIES TIME (PST) TRANSECT POINT # VOLUNTARY / PLAYBACK Feb Western screech-owl 18:13 Oktwanch 3 PLAYBACK Feb Western screech-owl 22:29 Vernon Lake 4 VOLUNTARY Feb Great horned owl 20:12 Sebalhall 7 VOLUNTARY Feb Northern pygmy-owl 18:41 Noomas 10 PLAYBACK Feb Western screech-owl 22:13 Klak. Lake 3 VOLUNTARY Feb Western screech-owl 19:02 Vernon Lake 7 PLAYBACK Feb Western screech-owl 21:31 Iron Mine 9 VOLUNTARY Feb Western screech-owl 23:11 Oktwanch 3 VOLUNTARY Feb Northern pygmy-owl 20:17 Noomas 6 PLAYBACK Feb Western screech-owl 21:52 Klak. Lake 7 PLAYBACK Table 4. Summary of Phase II 2003 Nimpkish Owl Survey detections. DATE SPECIES TIME (PST) TRANSECT POINT # VOLUNTARY / PLAYBACK Mar Northern pygmy-owl 23:34 Mt Cain 9 PLAYBACK Mar Western screech-owl 20:01 Klak Lake 3 PLAYBACK Mar Western screech-owl 23:37 Vernon Lake 9 PLAYBACK Mar Western screech-owl 23:59 Vernon Lake 8 PLAYBACK Mar Barred Owl 00:17 Vernon Lake 10 PLAYBACK Mar Western screech-owl 21:11 Oktwanch 2 PLAYBACK Mar Western screech-owl 21:13 Oktwanch 2 PLAYBACK Mar Western screech-owl 22:38 Oktwanch 4 PLAYBACK Mar Western screech-owl 21:13 Woss Lake 10 PLAYBACK Mar Western screech-owl 21:47 Iron Mine 8 PLAYBACK Mar Western screech-owl 21:51 Iron Mine 1 PLAYBACK Mar Northern pygmy-owl 19:33 Iron Mine 4 PLAYBACK Mar Western screech-owl 00:13 Huson Lake 1 PLAYBACK Apr Western screech-owl 20:03 Sebalhall 6 PLAYBACK Apr Western screech-owl 20:34 Sebalhall 7 PLAYBACK Apr Northern Saw-whet owl 21:38 Noomas 3 PLAYBACK Apr Great Horned Owl 21:40 Noomas 7 PLAYBACK WRM Resource Consulting, Ltd. March

13 CONCLUSIONS Phase I of the 2003 Nimpkish Owl Survey saw ten owl transects, each consisting of ten survey points, sampled twice from February 10 to February 25, There were ten owl detections, of which two were northern pygmy-owls, seven were western screech-owls and one was a great horned owl. Phase I was designed to fulfil the requirements of two different studies: the BC Nocturnal Owl Survey and Canfor s Nimpkish Owl Survey, which targeted northern pygmy-owls. Only NPOW calls were broadcast at each survey point after a two minute voluntary listening period. Phase II of the 2003 Nimpkish Owl Survey was completed from March 10 through April 2, The ten owl transects were sampled one additional time, but taped calls were played for all five of the owl species known to occur on TFL 37. There were 17 owl detections, including two northern pygmy-owls, one northern saw-whet owl, 12 western screech-owls, one barred owl and one great horned owl. The Nimpkish Owl Survey should provide useful information about owl population trends in the Nimpkish Valley, as well as providing a baseline from which to continue with further owl research. DISCUSSION AND RECOMMENDATIONS The current (Phase II) methodology was based on the raptor survey protocols according to the Resource Inventory Standards Committee (RIC, 2001). Owl surveys have now been conducted for eight of the past 11 years on TFL 37 by Wayne Matkoski and Andy Smith. The surveying period has ranged from January through May, but typically most owl surveying on TFL 37 has been completed during the months of February through April. Over the past 11 years there has been some variation in the surveying methodologies, but RIC/RISC is now the standard. Fortunately the RIC standard allows the flexibility to meet the survey requirements of the BCNOS. The results from Phase I and Phase II of the 2003 Nimpkish Owl Survey show that there was a total of five voluntary detections (out of ten) during Phase I and zero voluntary detections (out of 17) during Phase II. Therefore only five out of the 27 owl detections from the 2003 Nimpkish Owl Survey were voluntary. This translates to five voluntary detections out of 300 survey points (1.67% voluntary detection rate). In contrast, the tape playback solicited 22 responses out of 295 points (300 minus the five voluntary detections), or a 7.46% detection rate. The tape playback, therefore, resulted in approximately four and a half times greater detection rate as the voluntary during the 2003 Nimpkish Owl Survey. One issue with the tape playback (i.e. RISC/RIC) versus the voluntary (i.e. BCNOS) survey methods is the much greater time it takes to do a tape playback survey, especially targeting five owl species to RISC standard. While it requires only two minutes to do a voluntary survey, it takes approximately 40 minutes to complete a survey point to RISC standard (including the two WRM Resource Consulting, Ltd. March

14 minute BCNOS voluntary listening period). It also takes from seven to ten minutes to write notes and drive to the next point (assume eight minutes for simplicity), thereby making each point 48 minutes. At ten points per transect, that totals 480 minutes, or eight hours to complete a transect. Driving times of up to one hour at each end has to be considered as well. Surveying start times (based on the earliest starting time being one half hour after sunset) ranged from approximately 17:45 to 19:25 as the daylight hours became longer from February through April. Surveyors require Canfor First Aid coverage while conducting surveys on TFL 37. First Aid worked until approximately 00:30 to 01:00 each morning. Since surveys were taking approximately eight hours to complete, it was not possible for one person to complete one owl transect during Phase II of the survey. Surveyors either had to re-visit a transect another evening (then begin another transect) or two surveyors had to share a transect. Both of these scenarios were inefficient, plus it meant a particular transect may have had two start times and different weather conditions. There are three options to consider if these problems are to be addressed. Firstly, the surveying methodology can be changed to reduce the time spent listening for owls at each point. Secondly, the First Aid may be able to stay on duty longer each shift to accommodate owl surveyors. Thirdly, surveyors could reduce the number of owl species that are currently being solicited from five to four (or even three). Incurring more costs by keeping a First Aid attendant on duty potentially addresses the problem of completing a whole transect on one shift, but adversely affects the overall cost of the project. Also, based on our surveying experience, a shift of up to ten hours is too long for surveyors to endure at that time of the day. Surveying would also occur well outside the recommended surveying time of one half hour after sunset to approximately midnight (BCNOS). Reducing the number of owl species surveyed for is very feasible and should be considered by the project co-ordinator. Dropping one species would automatically reduce surveying time and cost by approximately 20%. That would reduce the surveying time for a transect to approximately 6.4 hours, while maintaining the RISC surveying standard. The problem would be that future surveys would be incomplete in surveying for the five owl species known to occur in TFL 37. If this method were to be considered, we would recommend that GHOW call playback be dropped based on the apparent low number of GHOWs occurring in TFL 37. Based on the past 11 years of surveying experience on TFL 37, the preferred time-saving mechanism would be to decrease the amount of time spent waiting after call playback. During surveys conducted in 1996, the survey protocol specified waiting only 45 seconds between sets of playback calls for each species, yet the number of detections was relatively high (Matkoski, 1997). As well, there were no owls detected beyond three minutes (n=6) of listening during Phase II of the 2003 survey. It may, therefore, be unnecessary to wait five minutes after each series of playback calls. We believe two or three minutes of listening after each individual owl WRM Resource Consulting, Ltd. March

15 species call series is adequate to produce similar results to Phase II of the 2003 survey. This would reduce the amount of time spent at each survey point, thereby reducing the time spent at each survey transect and greatly reducing the overall cost of the project. If two minutes were subtracted from the five minute listening period for each of the five species at all ten points on a transect, that would reduce the transect completion time to approximately 6.3 hours instead of the eight hours required currently. If three minutes were subtracted, then a transect could be completed in approximately 5.5 hours. Based on our years of surveying experience, the efficiency of a single surveyor completing a transect during one evening, plus the cost savings, we are recommending that the 2004 Nimpkish Owl Survey methodology be changed to a three minute listening period (rather than the current five minute) after each owl species call series have been played. This arrangement would not be in accordance with current RISC standards, but data collected during this and other surveys will still prove useful and can be compared to other owl surveys, even those following the RISC standard more closely. It should be noted that the Nimpkish Owl Survey targets five owl species, thereby introducing its own unique set of problems and differences to other owl surveys in BC. Having a different listening period than what the RISC standard recommends is the preferred way to make the surveys more efficient and reduce costs. The RISC raptor survey standard includes references to Deal and Lamont (which are the Nimpkish Owl Inventories from 1995 and 1996 overseen/conducted by Wayne Matkoski and Andy Smith) when discussing that owls may take a long period of time to respond to tape playback. It seems clear that previous Nimpkish Owl Inventory reports were relied upon when the RISC standard was developed. As well, one of the primary authors of the raptor surveying standard, Micheal Setterington, did his practical owling experience with Wayne Matkoski during the 1997 Nimpkish Owl Inventory. Unfortunately it seems that a maximum length of listening time was included in the RISC survey standards, rather than a reasonable length of time. While it is definitely true (based on our surveying experience) that the occasional owl will respond several minutes after tape playback ceases, it would be more accurate to call it a rare event in our opinion. Therefore we have the opinion that it is ineffective and a waste of resources to listen longer than three minutes after playing taped calls. It is also recommended that the RISC standards committee be notified that the Nimpkish Owl Survey surveying methodology will be changed for 2004, and that the committee consider changing the listening period from five minutes to three minutes. The Nimpkish Owl Survey consists of ten transects each with ten points. The BCNOS asks surveyors to rate the noise level (from streams, wind, traffic, croaking frogs, etc.) at each point when surveys are conducted. The noise level is rated from 1 to 4, with 1 being very quiet and a 4 rating being very noisy. Stream noise is the major noise factor. Out of the 100 points established for the Nimpkish Owl Survey, there are three points that are located directly beside loud streams. These three points always receive a 4 on the noise level rating. The three points are: #2 on the WRM Resource Consulting, Ltd. March

16 Huson Lake transect, which is situated beside Wolfe Creek; #4 on the Huson Lake transect, which is situated beside Atluck Creek; #9 on the Klaklakama Lake transect, which is situated beside Quilla Creek. It would be basically impossible to hear an owl calling at these points, even if the owl was very close to the surveyor. We recommend that these three points be permanently relocated/added to the ends of their respective transects for the 2004 Nimpkish Owl Survey. LITERATURE CITED B.C. Conservation Data Centre, Endangered Species in British Columbia. B.C. Ministries of Sustainable Resource Management and Water, Land & Air Protection (Date of Access: March 26, 2003) AXYS, Owl abundance and habitat in the Nimpkish Valley, Vancouver Island., Prepared for Canadian Forest Products, Ltd., Woss, B.C. AXYS, TFL 37 Owl Inventory 2002: Focal Species - Northern Pygmy Owl. Prepared for Canadian Forest Products,, Woss, B.C. 18 pp. Campbell, R.W. et al., The birds of British Columbia, Volume 2. Mitchell Press, Vancouver, B.C., 636 pp. Cannings, R. J., B.C. Nocturnal Owl Survey Protocol. Bird Studies Canada (Date of Access: March 1, 2003) Deal, J.A. and Lamont, N., Nimpkish owl inventory Progress Report. Canadian Forest Products, Ltd., Woss, B.C. 35 pp. Fraser, D.F., Harper, W.L., Cannings, S.G. and Cooper, J.M., Rare birds of British Columbia. Wildl. Branch and Resour. Inv. Branch, B.C. Minist. Environ., Lands and Parks, Victoria, B.C pp. Fuller, M.R. and Mosher, J.A., Methods of detecting and counting raptors: a review. In: J.M. Scott (Editor), Estimating the number of terrestrial birds. Stud. Avian Biol. #6, pp Lessard, S., Forest birds of the Nimpkish Valley. Canadian Forest Products, Ltd., Woss, B.C. 47 pp. Matkoski, W.R., Nimpkish Owl Inventory Progress Report., Canadian Forest Products, Ltd., Woss, B.C. 36 pp. Resource Inventory Committee, Inventory methods for raptors. Standards for components of British Columbia's biodiversity #11, Version 2.0. Environment Inventory Branch, B.C. Ministry of Sustainable Resource Management (Date of Access: February 1, 2003) Smith, C.F., Distributional ecology of barred and great horned owls in relation to human distribution. M.Sc. Thesis, University of Connecticut. WRM Resource Consulting, Ltd. March

17 APPENDIX I Map of Study Area TFL 37 showing Nimpkish Owl Survey transects and stations. WRM Resource Consulting, Ltd. March