Western Riverside County Multiple Species Habitat Conservation Plan Biological Monitoring Program
2013 Northern Goshawk (Accipiter gentilis) Survey Report
25 July 2014 2013 Northern Goshawk Survey Report
TABLE OF CONTENTS INTRODUCTION ...... 1
GOALS AND OBJECTIVES ...... 2 METHODS ...... 4
SURVEY DESIGN ...... 4
FIELD METHODS ...... 4
TRAINING ...... 8
DATA ANALYSIS ...... 8 RESULTS ...... 8
DISCUSSION ...... 9
RECOMMENDATIONS ...... 11 ACKNOWLEDGEMENTS ...... 12
REFERENCES ...... 12
LIST OF TABLES AND FIGURES Figure 1. Northern Goshawk Bioregions designated by the MSHCP and incidental detection of goshawk in Wilson Valley in 2010...... 3
Figure 2. Northern Goshawk survey polygons and survey stations within each polygon in northern San Jacinto Mountains Bioregion in 2013 ...... 5
Figure 3. Northern Goshawk survey polygons and survey stations within each polygon in central San Jacinto Mountains Bioregion in 2013 ...... 6
Figure 4. Northern Goshawk survey polygons and survey stations within each polygon in southern San Jacinto Mountains Bioregion (Thomas Mountain) in 2013 ...... 7
Table 1. Number of stations surveyed by polygon and survey round ...... 9
LIST OF APPENDICES Appendix A. Northern Goshawk survey data sheet ...... 15
Appendix B. Avian species detected during Northern Goshawk surveys in 2013 ...... 16
Western Riverside County MSHCP ii Biological Monitoring Program 2013 Northern Goshawk Survey Report
NOTE TO READER: This report is an account of survey activities conducted by the Biological Monitoring Program for the Western Riverside County Multiple Species Habitat Conservation Plan (MSHCP). The MSHCP was permitted in June 2004. Reserve assembly is ongoing and is expected to take 20 or more years to complete. The Conservation Area includes lands acquired under the terms of the MSHCP and other lands that have conservation value in the Plan Area (called public or quasi-public lands in the MSHCP). In this report, the term “Conservation Area” refers to these lands as they were understood by the Monitoring Program at the time the surveys were conducted. The Monitoring Program monitors the status and distribution of the 146 species covered by the MSHCP within the Conservation Area to provide information to Permittees, land managers, the public, and the Wildlife Agencies [i.e., the California Department of Fish and Wildlife (CDFW, formerly California Department of Fish and Game) and the U.S. Fish and Wildlife Service]. Monitoring Program activities are guided by defined conservation objectives for each Covered Species, other information needs identified in MSHCP Section 5.3 or elsewhere in the document, and the information needs of the Permittees. A list of the lands where data collection activities were conducted in 2013 is included in Section 7.0 of the Western Riverside County Regional Conservation Authority (RCA) Annual Report to the Wildlife Agencies. The primary author of this report was the 2013 Northern Harrier Project Lead, Masanori Abe. This report should be cited as: Biological Monitoring Program. 2014. Western Riverside County MSHCP Biological Monitoring Program 2013 Northern Goshawk (Accipiter gentilis) Survey Report. Prepared for the Western Riverside County Multiple Species Habitat Conservation Plan. Riverside, CA. Available online: http://www.wrc-rca.org/library.asp. While we have made every effort to accurately represent our data and results, it should be recognized that data management and analysis are ongoing activities. Readers wishing to make further use of the information or data provided in this report should contact the Monitoring Program to ensure that they have access to the best available or most current data. Please contact the Monitoring Program Administrator with questions about the information provided in this report. Questions about the MSHCP should be directed to the Executive Director of the RCA. Further information on the MSHCP and the RCA can be found at www.wrc-rca.org. Contact Information: Executive Director Western Riverside County MSHCP Western Riverside County Monitoring Program Administrator Regional Conservation Authority c/o Adam Malisch Riverside Centre Building 4500 Glenwood Drive, Bldg. C 3403 10th Street, Suite 320 Riverside, CA 92501 Riverside, CA 92501 Ph: (951) 248-2552 Ph: (951) 955-9700
Western Riverside County MSHCP iii Biological Monitoring Program 2013 Northern Goshawk Survey Report
INTRODUCTION The Northern Goshawk (Accipiter gentilis; goshawk) is one of 45 bird species covered by the Western Riverside County Multiple Species Habitat Conservation Plan (MSHCP) and is designated as a species of special concern at the state and federal levels (Dudek & Associates 2003; Squires and Kennedy 2006). The Plan lists three species- specific objectives. Objective 1 requires that at least 34,020 ac (13,767 ha) of suitable nesting and wintering habitat be conserved in deciduous woodland and montane coniferous forest within the Plan Area, specifically in the San Jacinto Mountains and San Bernardino Mountains Bioregions (Dudek & Associates 2003). Objective 2 specifies that the two known nesting locations shall be buffered from human disturbance by a 250-m radius during the breeding season and at least 1.6 sq. km of suitable nesting habitat will be conserved around each nest site. The same protection will be given to any additional nesting locations identified in the future. Objective 3 requires the continued use of, and successful reproduction at ≥75% of known nesting localities at least once every three years (Dudek & Associates 2003). Goshawks are widely distributed in the temperate zone of the northern hemisphere. In North America, the species inhabits and breeds in most areas except the south-central and southeastern parts of the U.S. (Squires and Reynolds 1997). In California, goshawks are common forest inhabitants in the north and within the Sierra Nevada, but they are extremely rare south of the Sierra Nevada (Keane 2008). The number of goshawks rapidly declined in the 20th century, primarily due to habitat loss associated with logging, agriculture, and urban development (Squires and Kennedy 2006). However, the estimates of goshawk population trends in the U.S. are poorly understood because of the difficulty of detecting individuals during long-term population surveys such as the Breeding Bird Survey (Keane 2008). Throughout the Sierra Nevada and northern California, Keane (2008) estimated there were approximately 1,000 breeding pairs between 1970 and 2000, but fewer than 20 breeding attempts were reported in southern California from 1958-2008. Goshawks in southern California typically nest in mature deciduous forest and montane coniferous forest from 2,000 to 2,700 m in elevation (Garrett and Dunn 1981). Within our Bioregions, the dominant tree species that goshawks previously used for nesting, foraging, and wintering were canyon live oak (Quercus chrysolepis) and California black oak (Q. kelloggii) in deciduous woodlands, and Jeffrey pine (Pinus jeffreyi), white fir (Abies concolor), and California incense-cedar (Calocedrus decurrens) in montane coniferous forest. High canopy closure and open understory are the most uniform characteristics of goshawk nest sites (Squires and Kennedy 2006). Goshawks may use areas with canopy cover <60%, but occupancy rates tend to increase with denser canopy cover (Reynolds et al. 1982; Hayward and Escaño 1989). Nest-stand sizes and home ranges are variable, approximately 10–100 ha and 570–3,500 ha, respectively (Reynolds et al. 1982; Woodbridge and Detrich 1994; Squires and Reynolds 1997). Goshawks usually have 1–5 alternative nest areas within a territory and they are an average of 0.27 km away from each other, with a maximum distance of 2 km between alternative nests in California (Woodbridge and Detrich 1994). Microhabitat preferred for
Western Riverside County MSHCP 1 Biological Monitoring Program 2013 Northern Goshawk Survey Report
nesting is large trees (diameter at breast height >40 cm; Siders and Kennedy 1996), and the density of those large trees is higher at nest sites than at random sites (Squires and Kennedy 2006). Goshawks usually select the largest tree in a nest stand as a nest substrate, build their nest in the lower third of the tree or in the lowest level of the canopy, and then conceal it within vegetation (Reynolds et al. 1982). They typically select nest trees that are at the bottom of moderately steep slopes that face north or east, which keeps the temperature in the nest low during the day (Reynolds et al. 1982; Squires and Ruggiero 1996). An active nest includes fresh green vegetation, usually conifer sprigs, especially during the nest-maintenance or -building stages (Roberson et al. 2005). Goshawks arrive at nesting sites in March and begin laying 3–5 eggs in late April to early May in northern areas such as Oregon (Bull and Hohmann 1994). There are no data for nesting dates in southern California, but nesting stages here are likely earlier than in more northern latitudes (Baker 1939). Females lay one egg every 2–3 days in the early morning (Squires and Reynolds 1997), and only the female incubates the eggs. Incubation lasts 32–38 days (Squires and Reynolds 1997), after which nestlings remain in the nest for 35–42 days (Boal 1994). Both parents care for the fledglings for approximately 30 days (Kennedy et al. 1994). In the San Jacinto Mountains Bioregion, goshawks were previously detected in Humber Park, Lake Fulmor, Tahquitz Valley, Willow Creek, and Skunk Cabbage (Garrett and Dunn 1981, Dudek & Associates 2003) although only Humber Park and Lake Fulmor occur within the Plan Area. Additionally, within the Plan Area, goshawk nesting has been documented at the Lake Fulmor /Lawler Lodge area and at one unknown location in the San Jacinto Wilderness both in 1998 (Dudek & Associates 2003). Monitoring Program biologists have detected just one goshawk within the Plan Area in the last eight years, in the Wilson Valley area in July 2010 (Fig. 1). For this project we delineated apparently suitable habitat (polygons) within the San Jacinto Mountains Bioregion, then distributed survey stations (i.e., points) within the polygons. We surveyed each station for goshawk occupancy by broadcasting conspecific vocalizations. Only a small portion of the San Bernardino Mountains Bioregion occurs in the Plan Area, and much of the habitat is dominated by chaparral or lacks the habitat that goshawks are known to prefer. We consequently did not survey in this Bioregion. Goals and Objectives 1. Determine whether Northern Goshawks are using the San Jacinto Mountains Bioregion. a. Broadcast conspecific vocalizations during point-count surveys within appropriate habitat of the Bioregion. 2. Determine breeding status of Northern Goshawks. a. Conduct nest searches and monitor active nests.
Western Riverside County MSHCP 2 Biological Monitoring Program Ä60
CALIMESA San Bernandino ¦¨§15 Mountains 215 Bioregion EASTVALE ¦¨§ ¦¨§10 RIVERSIDE Ä60 BEAUMONT Ä BANNING NORCO MORENO VALLEY Ä71 Ä91 Ä79
CORONA Ä243 Ä Figure 2
215 ¦¨§15 ¦¨§ SAN JACINTO Figure 3 PERRIS
Ä74 Ä HEMET Ä74 Ä74 San Jacinto Mountains CANYON LAKE MENIFEE Bioregion
LAKE ELSINORE 215 ¦¨§ Figure 4
WILDOMAR Ä79 ¦¨§15 MURRIETA *# ÄÄ371 Legend *# NOGO Incidental Detection TEMECULA Ä79 NOGO Survey Area Highways ¦¨§15 Water Bodies Date: 14 March 2014 Existing Conservation Land UTM Nad 83 Zone 11 Cities km Contact: Masanori Abe I 0 2.5 5 10 15 20 MSHCP Biological Monitoring Program
Figure 1. Northern Goshawk Bioregions designated by the MSHCP and incidental detection of goshawk in Wilson Valley in 2010. 2013 Northern Goshawk Survey Report
3. Estimate detection probabilities based on presence or absence of Northern Goshawks at survey stations. a. Conduct repeat-visit broadcast surveys within the Bioregion and use a closed-capture occupancy model included with Program MARK (White and Burnham 1999).
METHODS Survey Design Our survey area was focused in the San Jacinto Mountains Bioregion, specifically, lands in the San Bernardino National Forest and Mount San Jacinto State Park (Figs 2-4). The Plan Area does not include the entirety of the Bioregion, so we were limited to surveying approximately the western half of the Bioregion. We used Google Earth (version 5.2) satellite photos to delineate blocks of apparently suitable habitat (polygons) and visited these polygons prior to surveys to determine whether suitable goshawk nesting habitat was actually present. We then converted the polygons to ArcGIS (ESRI 2009) and used Hawth’s Tools (Beyer 2004) to distribute regularly spaced points within the polygons. We conducted broadcast surveys for goshawks by using the survey methodology described by Kennedy and Stahlecker (1993) within apparently suitable goshawk habitat. We distributed 198 survey stations across the 28 polygons that we determined contained suitable habitat (Figs 2-4). Polygons varied in size from 12 to 140 ha and we distributed up to 16 survey stations in each polygon. Stations within each polygon were 300 m apart and in a staggered pattern designed to ensure 90% coverage of the area (Joy et al. 1994). We planned to visit each station a minimum of three times during March-August 2013 to increase our detection probability to approximately 90% (Watson et al. 1999). We broadcast alarm calls during the courtship, egg-laying, incubation, and early to mid-nestling periods (i.e., March-July), then food-begging calls during late nestling and fledgling-dependency periods (i.e., August) (Kennedy and Stahlecker 1993). Roberson et al. (2005) reported that the rate of goshawk response is the highest during the courtship and fledgling-dependency periods, and the lowest during the incubation periods. We chose to conduct surveys throughout the breeding season because we do not know the exact timing of the different periods / breeding phases in southern California. We started surveys at sunrise and we did not start any new surveys after noon. Finally, we did not conduct surveys during periods of rain, heavy fog, or high winds (>24 km/hr) (Kennedy and Stahlecker 1993). Field Methods We began by navigating to the first survey station in the survey polygon using a handheld GPS unit. Upon arrival, we recorded on the data sheet the date, observer’s initials, survey station and polygon numbers, ambient noise, and weather code (Appendix A). We hung the anemometer from nearby vegetation to record conditions during the length of the survey. We then set up the broadcasting equipment. We used a single Foxpro Wildfire speaker (Foxpro Inc., Lewistown, PA) that produced sound pressure of 100 dB at a distance of 1 m from the speaker. This value is within the range (100-110 dB)
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!( !( !( !( !( Sources: Esri, DeLorme, NAVTEQ, TomTom, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, !(NRCA!(N, Ge!(oBase!(, IGN, Kadaster NL, Ordnance Survey, Esri Japan, METI, E!(sri Ch!(ina (Hong Kong), swisstopo, and the GIS User Community !( !( !( Date: 14 SMtraarwcbhe 2rr0y1 C4reekStrawberry Creek South Stone Creek North Stone Creek UTM Nad 83 Z!(one 1!(1 km Contact: Masanori Abe I 0 0.5 1 2 3 4 MSHCP Biological Monitoring Program Figure 2. Northern Goshawk survey polygons and survey stations within each polygon in northern San Jacinto Mountains Bioregion in 2013. !( !( !( !( !( !(
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Date: 14 March 2014 UTM Nad 83 Zone 11 km Contact: Masanori Abe I 0 0.5 1 2 3 4 MSHCP Biological Monitoring Program Figure 3. Northern Goshawk survey polygons and survey stations within each polygon in central San Jacinto Mountains Bioregion in 2013. !( !(
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Date: 14 March 2014 UTM Nad 83 Zone 11 km Contact: Masanori Abe I 0 0.275 0.55 1.1 1.65 2.2 MSHCP Biological Monitoring Program Figure 4. Northern Goshawk survey polygons and survey stations within each polygon in southern San Jacinto Mountains Bioregion (Thomas Mountain) in 2013. 2013 Northern Goshawk Survey Report
that Fuller and Mosher (1987) recommended for goshawk broadcast surveys. The survey officially began when the first recorded vocalization was broadcast; the start-time was recorded on the data sheet. We broadcast a series of conspecific vocalizations in three directions from the survey station, at intervals of 120 degrees. The first direction was randomly selected and the speaker was turned in a clockwise direction for subsequent broadcasts. The audio files consisted of three cycles: two cycles of 10-second alarm or begging calls followed by 30- second silent periods, and the final cycle consisted of 10 seconds of calls followed by a 60-second silent period. Our visual and auditory observation period began when the first call started and terminated at the end of the 60-second silent period. At the end of the survey, we recorded the survey end time, temperature, and maximum and average wind speeds. We then collected the equipment and navigated to the next station, walking at a casual pace while remaining alert for goshawk calls and signs. We recorded information on all bird species detected during the period of broadcasting. For non-covered species, we recorded information for only the first individual of the species detected, which provides richness data for the site. For such species, we recorded the species name, age class, and sex. For Covered Species, we recorded the species name, age class, and sex for every individual detected. If we were unsure whether we had already recorded data on an individual (i.e., we may be double- counting), we erred on the side of caution and recorded information on that individual. Training Participants demonstrated the ability to identify bird species likely to be detected near goshawk survey areas before being allowed to participate in this project. To demonstrate this, participants had to pass a quiz consisting of photographs and audio recordings of 64 bird species that may co-occur with goshawks. They had to correctly identify every Covered Species and ≥80% of the non-covered species on the quiz. Participants studied avian field guides (e.g., Sibley 2000) and computer software to learn to identify birds by sight and sound. Additionally, participants attended a presentation by the Avian Program Lead during which we discussed the protocol, goshawk identification, and any questions related to the project. Data Analysis The survey method was designed to enable us to calculate robust detection probabilities and to develop a closed-capture occupancy model for this species (White and Burnham 1999). We were unable to conduct these analyses due to lack of data.
RESULTS We surveyed for Northern Goshawk from 26 March through 30 August 2013. We did not detect goshawks during surveys nor did we detect any sign that goshawks were using the San Jacinto Mountain Bioregion during this or other MSHCP mountain bird surveys. We detected a total of 73 avian species, including eight Covered Species (Appendix B). One of these, Cooper’s Hawks (Accipiter cooperii), responded to the goshawk call six times during surveys and five times following surveys.
Western Riverside County MSHCP 8 Biological Monitoring Program 2013 Northern Goshawk Survey Report
We surveyed for goshawks at 182, 182, and 164 survey stations from 28 polygons that covered a total of 1,546 ha in the first, second, and third rounds, respectively (Table 1). The stations and polygons we surveyed varied by round for several reasons. During the first round snow prevented access to the 11 stations in the Seven Pines Trail polygon and we eliminated five stations in the North Fork polygon due to poor quality habitat. We were subsequently able to access the Seven Pines Trail polygon during the second round but dropped 11 stations across two other polygons because of poor quality habitat. Finally, we were unable to survey 16 stations during the third round because of either lack of staff or wildfire, which also delayed the third round of surveys by several weeks.
Table 1. Number of stations surveyed by polygon and survey round. Stations Surveyed Round 1 Round 2 Round 3 Number of (26 Mar – (30 Apr – (17 Jun – Polygon Name Size (ha) Stations 29 Apr) 17 Jun) 30 Aug) Black Mountain 1 95.1 11 11 11 11 Black Mountain 2 17.9 4 4 4 4 Black Mountain 3 21.4 3 3 3 3 Black Mountain Campground 24.7 5 5 5 5 Little Round Valley 50.2 6 6 6 6 Seven Pines Trail 90.3 11 0 11 11 Deer Springs 51.0 7 7 7 7 Lake Fulmor 1 17.7 3 3 3 3 Lake Fulmor 2 50.5 7 7 7 7 Fuller Mill Creek 56.5 9 9 9 9 Black Mountain Creek 1 11.4 2 2 2 2 Black Mountain Creek 2 50.7 6 6 6 6 Dark Canyon 35.5 4 4 4 4 Marion Mountain Campground 76.2 9 9 9 5 Marion Mountain Trail 79.4 10 10 10 10 North Fork 104.8 14 9 0 0 Strawberry Junction 126.8 15 15 15 15 North Stone Creek 107.4 13 13 13 13 Strawberry Creek 64.2 7 7 7 7 South Stone Creek 139.8 16 16 16 16 Logan Creek 77.3 10 10 10 10 Alvin Meadow 29.3 4 4 2 2 May Valley 1 11.5 1 1 1 0 May Valley 2 21.9 4 4 4 0 Thomas Mountain 1 21.3 2 2 2 2 Thomas Mountain 2 30.6 4 4 4 0 Thomas Mountain 3 24.9 3 3 3 0 Thomas Mountain 4 58.2 8 8 8 8 Total 1,546.5 198 182 182 166
DISCUSSION We did not detect any goshawks in the San Jacinto Mountains Bioregion during the breeding season of 2013, which is the same result as our last survey in 2008.
Western Riverside County MSHCP 9 Biological Monitoring Program 2013 Northern Goshawk Survey Report
Consequently, MSHCP species objectives were not met this survey year. Moreover, we did not find any signs of goshawks (i.e., feathers, previous nests) using the Plan Area. Approximately 25 goshawks have been observed south of the Sierra Nevada during the breeding season during the 50 years to 2008 (Keane 2008) and about half of these detections occurred in the San Jacinto Mountains, but some of those reports were suspect due to lack of detailed information. U.S. Forest Service biologists have periodically surveyed for California Spotted Owls (Strix occidentalis occidentalis), which share similar habitat preferences as goshawks (Gutiérrez et al. 1995), but they have not observed goshawks recently (A. Poopatanapong, U.S. Forest Service, pers. comm.). Overall, our results support Keane’s report (2008) that extremely few breeding attempts of goshawks have been documented in southern California. The San Jacinto Mountains Bioregion is at the southern edge of the species’ range, so goshawks are only temporarily using the Plan Area on rare occasions, not on a regular basis. While conducting surveys in the San Jacinto Mountains Bioregion we observed that much of the habitat was similar to that used by goshawks elsewhere in North America (e.g., Reynolds et al. 1982; Hayward and Escaño 1989; Siders and Kennedy 1996; Squires and Kennedy 2006). Habitat conditions, including stand size, seemed to be adequate for goshawks especially in Mount San Jacinto State Park between 1,800 and 2,500 m. In the State Park, between Strawberry Junction and the junction of Marion Mountain and Seven Pines Trails (JMS) along the Pacific Crest Trail (Fig. 2), coniferous trees were large (60 cm diameter), and density of trees and condition of understory vegetation provided suitable breeding habitat. Areas along Seven Pines Trail from the North Fork of the San Jacinto River (i.e., the northwest edge of the Seven Pines Trail Polygon) to JMS, and Marion Mountain Trail near the campground to JMS, were also very good (Fig. 2). An area along Stone Creek, north of State Route 243, was another piece of apparently good habitat (Fig. 3). As a rule, above 2,500 m the ground became rockier, trees were generally smaller, and we observed only a few small patches of good habitat. Some of the areas we surveyed contained marginally suitable habitat. In the National Forest north of Lake Fulmor (Fig. 2), goshawks were previously reported several times, including a breeding pair in 1988 (Dudek & Associates 2003). This location had good habitat, but the patch was not large. In the areas along creeks on either side of State Route 243 (Fig. 2 and 3), we determined that habitat was marginal for goshawks because patches were relatively small and surrounded by chaparral; additionally, the elevation along this stretch of State Route 243 averages 1,500 m. The area along Strawberry Creek, north of Fern Valley (Fig. 3), had potential habitat for breeding, but the size of optimal habitat was small here, also. Near the top of Black Mountain Road and around Black Mountain Campground were suitable goshawk habitats (Fig. 2). Little suitable habitat existed on Thomas Mountain (Fig. 4). We were unable to survey all stations and/or all polygons as we had originally planned. Two large wildfires within the San Jacinto Mountains Bioregion in July and August 2013 caused us to suspend surveys while the National Forest and State Park were closed. Five stations in the two polygons in May Valley were not surveyed in the third round because of the Mountain Fire. Consequently, we were unable to conduct additional
Western Riverside County MSHCP 10 Biological Monitoring Program 2013 Northern Goshawk Survey Report
survey rounds. Finally, the periods of time between our survey rounds may have been so great that we failed to survey during at least one entire cycle of goshawk nesting. Cooper’s Hawks, which are closely related with Northern Goshawks and share similar breeding habitats (Curtis et al. 2006), responded to the goshawk broadcasting calls 11 times during and immediately following surveys. Two hawks called back and the rest of them silently approached and observed us. These responses lend credence to the effectiveness of the protocol and suggest that we would have detected goshawks within survey areas had they been present. We found one active Cooper’s Hawk nest while walking between survey stations. Signs of the active nest, such as whitewash, were observed at the base of the nesting tree. During point-count surveys, we detected many medium-sized birds such as Mountain Quail (Oreortyx pictus), Northern Flicker (Colaptes auratus), Band-tailed Pigeon (Columba fasciata), and Acorn Woodpecker (Melanerpes formicivorus) (Appendix B). These species, and others of similar size, have been reported as potential prey for goshawks in the north (Squires and Reynolds 1997). As a result, we suggest that it is unlikely that the availability of food is a limiting factor for goshawks within the Plan Area. Recommendations Although there is apparently suitable habitat in the San Jacinto Mountains Bioregion, our data corroborate Keane’s (2008) assertion that while individuals may be sporadically observed, we are unlikely to detect permanent breeding pairs of goshawks in the Plan Area. Additionally, although this and past survey efforts have been fairly intensive, they are only conducted every three years, adding to the difficulty in detecting a very scarce species. Consequently, communication with other organizations, such as the U.S. Forest Service, California Department of Parks and Recreation, and California Department of Fish and Wildlife to exchange reports of goshawk detections is very important. Broadcast polygon surveys conducted this year are more suitable to achieve our goals than the dawn vocalization surveys we conducted in 2008. The objective of dawn vocalization surveys is to confirm whether an active pair is re-using a known nesting territory (Penteriani 1999; Dewey 2003) but we lack data indicating where exactly goshawks nested historically within the Plan Area. Moreover, a single observer can cover just one survey station, which is near the previous nest site in the territory, per day so this method is very labor-intensive. If further targeted surveys are conducted, we should consider starting surveys in early March to complete more survey rounds, which will also increase the likelihood of detecting goshawks. Goshawks in southern California seem to start breeding earlier than those in northern regions and, since detections of goshawks by the broadcasting of conspecific calls during the courtship period are high (Roberson et al. 2005), we would not have any problems if we started the survey at the beginning of March. However, this strategy might conflict with snowy conditions in the mountains, hindering the accessibility of some areas especially at higher elevations. Even if we had to skip those
Western Riverside County MSHCP 11 Biological Monitoring Program 2013 Northern Goshawk Survey Report
survey stations during the first round, we might complete more survey rounds at lower elevations. Habitat in the area of Thomas Mountain, where we distributed 17 stations across four polygons, is of marginal quality. Given current staffing constraints and the potential for environmental conditions (e.g., wildfire) to restrict the overall number of surveys we conduct, we recommend that this area be the last surveyed during any given round. We should select survey polygons and stations for the next goshawk survey based on our efforts during this project. We identified potentially suitable habitat using aerial photos then visited each site to confirm its suitability. Sites that did not, in fact, contain suitable habitat were excluded from surveys, and those that were deemed to lack suitable habitat after the first round of surveys were subsequently excluded from further surveys. One site we did not survey in 2013, an area between Strawberry Junction and Strawberry Creek (Fig. 2-3), appears to contain suitable habitat and should be surveyed during the next effort.
ACKNOWLEDGEMENTS Funding for the Biological Monitoring Program is provided by the Western Riverside Regional Conservation Authority and the California Department of Fish and Wildlife. Program staff who conducted surveys were Masanori Abe (Project Lead), Jennifer Hoffman, Robert Packard, Ashley Ragsdale and Jonathan Reinig. We thank the land managers in the MSHCP Plan Area, who in the interest of conservation and stewardship facilitate Monitoring Program activities on the lands for which they are responsible.
REFERENCES Baker, J. R. 1939. The relation between latitude and breeding seasons in birds. Proceedings of the Zoological Society of London A108:557–582. Beyer, H. L. 2004. Hawth’s Analysis Tools for ArcGIS [software]. Available at http://www.spatialecology.com/htools. Boal, C. W. 1994. A photographic and behavioral guide to aging nestling Northern Goshawks. Studies in Avian Biology 16:32–40. Bull, E. L., and J. H. Hohmann. 1994. Breeding biology of Northern Goshawks in northeastern Oregon. Studies in Avian Biology 16:103–105. Curtis, Odette E., R. N. Rosenfield and J. Bielefeldt. 2006. Cooper's Hawk (Accipiter cooperii). In A. Poole, editor. The Birds of North America Online. Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.bnaproxy.birds.cornell.edu/bna/species/075 Dewey, S. R., P. L. Kennedy, and R. M. Stephens. 2003. Are dawn vocalization surveys effective for monitoring goshawk nest-area occupancy? Journal of Wildlife Biology 67:390–397.
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Dudek & Associates. 2003. Western Riverside County Multiple Species Habitat Conservation Plan (MSHCP). Final MSHCP, Volumes I and II. Prepared for County of Riverside County Transportation and Lands Management Agency by Dudek & Associates, Inc. Approved June 17, 2003. [ESRI] Environmental Systems Research Institute. ArcGIS: Release 9.3.1 [software]. 2009. Environmental Systems Research Institute, Redlands, CA. Fuller, M. R., and J. A. Mosher. 1987. Raptor survey techniques. Pages 37–65 in B. A. Giron Pendleton, B. A. Millsap, K. W. Cline, and D. M. Bird, editors. Raptor management techniques manual. National Wildlife Federation, Washington, D.C. Garrett, K., and J. Dunn. 1981. Birds of Southern California: Status and Distribution. Los Angeles Audubon Society, Los Angeles, CA. Gutiérrez, R. J., A. B. Franklin, and W. S. Lahaye. 1995. Spotted Owl (Strix occidentalis). In A. Poole, editor. The Birds of North America Online. Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.bnaproxy.birds.cornell.edu/bna/species/179. Hayward, G. D., and R. E. Escaño. 1989. Goshawk nest-site characteristics in western Montana and northern Idaho. Condor 91:476–479. Joy, S. M., R. T. Reynolds, and D. G. Leslie. 1994. Northern Goshawk broadcast surveys: Hawk response variables and survey cost. Studies in Avian Biology 16:24–30. Keane, J. J. 2008. Northern Goshawk (Accipiter gentilis). Pages 156–162 in W. D. Shuford WD and T. Gardali, editors. California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California. Studies of Western Birds 1. Western Field Ornithologists, Camarillo, CA, and California Department of Fish and Game, Sacramento, CA. Kennedy, P. L., and D. W. Stahlecker. 1993. Responsiveness of nesting Northern Goshawks to taped broadcasts of 3 conspecific calls. Journal of Wildlife Management 57:249–257. Kennedy, P. L., J. M. Ward, G. A. Rinker, and J. A. Gessaman. 1994. Post-fledging areas in Northern Goshawk home ranges. Studies in Avian Biology 16:75–82. Penteriani, V. 1999. Dawn and morning goshawk courtship vocalizations as a method for detecting nest sites. Journal of Wildlife Biology 63:511–516. Reynolds, R. T., E. C. Meslow, and H. M. Wight. 1982. Nesting habitat of coexisting Accipiter in Oregon. Journal of Wildlife Management 46:124–138.
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Roberson, A. M., D. E. Andersen, and P. L. Kennedy. 2005. Do breeding phase and detection distance influence the effective area surveyed for Northern Goshawks? Journal of Wildlife Management 69:1240–1250. Sibley, D. A. 2000. The Sibley guide to birds. Alfred A. Knopf, New York, NY. Siders, M. S., and P. L. Kennedy. 1996. Forest structural characteristics of accipiter nesting habitat: Is there an allometric relationship? Condor 98:123–132. Squires, J. R., and P. L. Kennedy. 2006. Northern Goshawk ecology: An assessment of current knowledge and information needs for conservation and management. Studies in Avian Biology 31:8–62. Squires, J. R., and R. T. Reynolds. 1997. Northern Goshawk (Accipiter gentilis). In A. Poole, editor. The Birds of North America Online. Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.bnaproxy.birds.cornell.edu/bna/species/298. Squires, J. R., and L. F. Ruggiero. 1996. Nest-site preference of Northern Goshawks in southcentral Wyoming. Journal of Wildlife Management 60:170–177. Watson, J. W., D. W. Hays, and D. J. Pierce. 1999. Efficacy of Northern Goshawk broadcast surveys in Washington State. Journal of Wildlife Biology 63:98–106. White, G. C., and K. P. Burnham. 1999. Program MARK: Survival estimation form populations of marked animals. Bird Study 46 Supplement: 120–138. Downloaded August 2009. Woodbridge, B., and P. J. Detrich. 1994. Territory occupancy and habitat patch size of Northern Goshawks in the southern Cascades of California. Studies in Avian Biology 16:83–87.
Western Riverside County MSHCP 14 Biological Monitoring Program 2013 Northern Goshawk Survey Report
Appendix A. Northern Goshawk survey data sheet.
MSHCP Northern Goshawk Survey Data Sheet, 2013 Sheet _____ of _____
Station ID: Polygon ID: Date: Observers: Visit #: Start time:
End temp.: ˚C Avg. sky code: Avg. noise: End time:
Max wind: km hr-1 Avg. wind: km hr-1 Bearing of first broadcast: Broadcast type: Alarm or Begging Goshawk detected? yes or no
Age Sex Species code (Ad, Juv, Unk) (M, F, Unk) Notes
Notes, species observed in-transit, etc.
Data Entered______, Checked______
Sky Condition Codes: 0 = clear or few clouds; 1 = partly cloudy; 2 = mostly cloudy; 3 = fog or smoke; 4 = light drizzle; 5 = constant snow; 6 = constant rain. Noise Codes: 0 = no noise; 1 = noise, but not affecting bird detection; 2 = moderate noise, may be affecting detection; 3 = loud noise, reducing ability to detect birds; 4 = very loud noise, difficult to hear anything.
Western Riverside County MSHCP Biological Monitoring Program 15 2013 Northern Goshawk Survey Report
Appendix B. Avian species detected during Northern Goshawk surveys in 2013. Species covered by the MSHCP are indicated in bold.
COMMON NAME SCIENTIFIC NAME
Acorn Woodpecker Melanerpes formicivorus American Crow Corvus brachyrhynchos American Kestrel Falco sparverius American Robin Turdus migratorius Anna's Hummingbird Calypte anna Ash-throated Flycatcher Myiarchus cinerascens Band-tailed Pigeon Patagioenas fasciata Bewick's Wren Thryomanes bewickii Black-chinned Sparrow Spizella atrogularis Black-headed Grosbeak Pheucticus melanocephalus Black-throated Gray Warbler Dendroica nigrescens Blue-gray Gnatcatcher Polioptila caerulea Brown Creeper Certhia americana Bushtit Psaltriparus minimus California Thrasher Toxostoma redivivum California Towhee Pipilo crissalis Canyon Wren Catherpes mexicanus Cassin's Finch Carpodacus cassinii Cassin's Vireo Vireo cassinii Clark's Nutcracker Nucifraga columbiana Common Raven Corvus corax Cooper's Hawk Accipiter cooperii Dark-eyed Junco Junco hyemalis Downy Woodpecker Picoides pubescens Dusky Flycatcher Empidonax oberholseri Fox Sparrow Passerella iliaca Green-tailed Towhee Pipilo chlorurus Hairy Woodpecker Picoides villosus House Finch Haemorhous mexicanus House Wren Troglodytes aedon Hutton's Vireo Vireo huttoni Lesser Goldfinch Spinus psaltria MacGillivray's Warbler Geothlypis tolmiei Mallard Anas platyrhynchos Mountain Chickadee Poecile gambeli Mountain Quail Oreortyx pictus Mourning Dove Zenaida macroura Nashville Warbler Oreothlypis ruficapilla Northern Flicker Colaptes auratus Nuttall's Woodpecker Picoides nuttallii Oak Titmouse Baeolophus inornatus Olive-sided Flycatcher Contopus cooperi Orange-crowned Warbler Oreothlypis celata
Western Riverside County MSHCP 16 Biological Monitoring Program 2013 Northern Goshawk Survey Report
Appendix B. Continued.
Pacific-slope Flycatcher Empidonax difficilis Pine Siskin Spinus pinus Pygmy Nuthatch Sitta pygmaea Red-breasted Nuthatch Sitta canadensis Red-breasted Sapsucker Sphyrapicus ruber Red-tailed Hawk Buteo jamaicensis Red-winged Blackbird Agelaius phoeniceus Rock Wren Salpinctes obsoletus Ruby-crowned Kinglet Regulus calendula Song Sparrow Melospiza melodia Spotted Towhee Pipilo maculatus Steller's Jay Cyanocitta stelleri Tree Swallow Tachycineta bicolor Turkey Vulture Cathartes aura Unidentified accipiter Accipiter spp. Unidentified flycatcher Family Tyrannidae Unidentified hummingbird Family Trochilidae Unidentified sapsucker Sphyrapicus spp. Unidentified vireo Vireo spp. Unidentified woodpecker Family Picidae Violet-green Swallow Tachycineta thalassina Warbling Vireo Vireo gilvus Western Bluebird Sialia mexicana Western Kingbird Tyrannus verticalis Western Scrub-Jay Aphelocoma californica Western Tanager Piranga ludoviciana Western Wood-Pewee Contopus sordidulus White-breasted Nuthatch Sitta carolinensis White-headed Woodpecker Picoides albolarvatus White-throated Swift Aeronautes saxatalis Williamson's Sapsucker Sphyrapicus thyroideus Wilson's Warbler Cardellina pusilla Wrentit Chamaea fasciata Yellow Warbler Setophaga petechia Yellow-rumped Warbler Setophaga coronata
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