Western Riverside County Multiple Species Habitat Conservation Plan Biological Monitoring Program

2019 Grasshopper Sparrow (Ammodramus savannarum) Survey and Nest Monitoring Report

Entrance of a Grasshopper Sparrow nest at the Santa Rosa Plateau. The nest contains five eggs.

15 April 2020 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

TABLE OF CONTENTS INTRODUCTION ...... 1

GOALS AND OBJECTIVES ...... 3

METHODS ...... 3

SURVEY DESIGN ...... 3

FIELD METHODS ...... 4

DATA ANALYSIS ...... 6

RESULTS ...... 6

DETECTIONS OF GRASSHOPPER SPARROWS ...... 6

DETECTION RATES AND DETECTION PROBABILITY ANALYSIS ...... 8

GRASSHOPPER SPARROW NESTING ...... 9

HABITAT ASSESSMENT ...... 9

DISCUSSION ...... 11

DETECTIONS OF GRASSHOPPER SPARROWS ...... 11

DETECTION RATES AND DETECTION PROBABILITY ANALYSIS ...... 13

GRASSHOPPER SPARROW NESTING ...... 14

HABITAT ASSESSMENT ...... 15

RECOMMENDATIONS ...... 16

ACKNOWLEDGEMENTS ...... 17

LITERATURE CITED ...... 18

LIST OF TABLES Table 1. The most recent detection of Grasshopper Sparrows within each of the designated Core Areas...... 8 Table 2. Model rankings for Grasshopper Sparrow surveys in 2019...... 9 Table 3. Summary of 2019 Grasshopper Sparrow nest counts, and the number of fledglings observed, by Core Area...... 9 Table 4. Grasshopper Sparrow habitat assessment data for used and available sites...... 11

LIST OF FIGURES Figure 1. Grasshopper Sparrow Core Areas and stations surveyed in 2019...... 2 Figure 2. Grasshopper Sparrow detections within the current reporting period (2015– 2019)...... 7 Figure 3. Locations of Grasshoppper Sparrow nests and fledglings found in 2019...... 10

Western Riverside County MSHCP ii Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

Figure 4. Frequency of aspects of sites used by Grasshopper Sparrows in 2019...... 11

LIST OF APPENDICES Appendix A. Avian species detected during 2019 Grasshopper Sparrow surveys...... 23

Western Riverside County MSHCP iii Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring 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 2019 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 2019 Avian Program Lead, Nicholas Peterson. This report should be cited as: Biological Monitoring Program. 2020. Western Riverside County MSHCP Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report. Prepared for the Western Riverside County Multiple Species Habitat Conservation Plan. Riverside, CA. Available online: http://wrc-rca.org/about-rca/monitoring/monitoring- surveys/. While we have made every effort to accurately represent our data and results, the reader should recognize that data management and analysis are ongoing activities. Anyone 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 Monitoring Program Administrator Western Riverside County Western Riverside County MSHCP Regional Conservation Authority Biological Monitoring Program Riverside Centre Building 1835 Chicago Ave., Suite C 3403 10th Street, Suite 320 Riverside, CA 92507 Riverside, CA 92501 Ph: (951) 320-2168 Ph: (951) 955-9700

Western Riverside County MSHCP iv Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

INTRODUCTION The Grasshopper Sparrow (Ammodramus savannarum) is one of 45 bird species covered by the Western Riverside County MSHCP (Dudek & Associates 2003) and is a Species of Special Concern in the State of California (Unitt 2008). The statewide population is considered greatly reduced (>40–80%) since population estimates reported by Grinnell and Miller (1944), with a current estimate of 10,000–100,000 birds (Unitt 2008). The range size of Grasshopper Sparrows in California is slightly reduced (>10– 20%) since the publication of Grinnell and Miller (1944). By 2028, habitat loss, habitat degradation, or other human-induced threats are projected to greatly reduce (>15–20%) the species’ population in California (Unitt 2008). The MSHCP identifies two species objectives for Grasshopper Sparrows. Objective 1 requires the conservation of at least 38,690 ac (15,657 ha) of suitable non- native, valley, and foothill grassland habitats. Objective 2 requires that the species maintain occupancy in three designated large (i.e., ≥809 ha of grassland or grassland- dominated habitat) Core Areas and at least three (75%) of four designated smaller (≥202 ha of grassland or grassland-dominated habitat) Core Areas in at least one year out of any five-consecutive-year period. The species account identifies 11 potential Core Areas, including Badlands, Box Springs, Kabian Park, Lake Mathews-Estelle Mountain, Lake Skinner/Diamond Valley Lake/Johnson Ranch, Mystic Lake/San Jacinto Wildlife Area (WA), Potrero, Prado Basin, Santa Rosa Plateau/Tenaja, Steele Peak, and Sycamore Canyon (Fig. 1). The Badlands and Potrero are both part of the Plan Area’s Core 3, so I combined them into a single Core Area for the purposes of this study. Five Core Areas currently contain at least 809 ha of grassland habitat and are thus considered large, and these include Badlands/Potrero, Lake Mathews-Estelle Mountain, Lake Skinner/Diamond Valley Lake/Johnson Ranch, Mystic Lake/San Jacinto WA, and Santa Rosa Plateau/Tenaja. Four additional Core Areas contain at least 202 ha, but less than 809 ha, of grassland habitat, and these include Box Springs, Kabian Park, Steele Peak, and Sycamore Canyon. Finally, one Core Area, Prado Basin, contains just 142 ha of grassland or grassland-dominated habitat, so does not technically qualify as a small Core Area; however, we surveyed habitat in this Core Area for Grasshopper Sparrows in 2019. Finally, Objective 2 also requires that five of seven designated Core Areas support at least 20 Grasshopper Sparrow pairs with evidence of successful reproduction within the first five years after permit issuance (2004–2009). This five-year period has already passed, and the objective was not met when our program conducted Grasshopper Sparrow surveys in 2005, but we incorporated a nest-searching and monitoring component in our 2019 surveys. The winter range of Grasshopper Sparrows in North America extends from portions of the southeastern U.S. south through much of Mexico. The species breeds in southern New England west to Montana, and south into northern Texas, Arkansas, Tennessee, and North Carolina, with a patchy distribution west of the Rockies (Vickery 1996). Grasshopper Sparrows in California occur west of the Sierra Nevada and are primarily summer residents (McCaskie et al. 1979; Garrett and Dunn 1981), from Mendocino, Tehama, and Trinity counties in the north, to western Riverside and San Diego counties in the south (Grinnell and Miller 1944). Within western Riverside

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Western Riverside County MSHCP 2 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

County, the species is found in suitable habitat within the Riverside Lowlands, San Jacinto Foothills, and Santa Ana Mountains Bioregions (Garrett and Dunn 1981), but predominantly within the central and south-central portions of the Plan Area (Dudek & Associates 2003); however, the species is currently considered rare and declining (Garrett et al. 2012). Throughout their range, Grasshopper Sparrows occupy sites with moderately open grasslands containing patches of bare ground (Vickery 1996; Elliott and Johnson 2017). Such grasslands in southern California can consist of native or non-native grasses 12–23 cm tall (Jobin and Falardeau 2010; Bogard and Davis 2014) and may contain scattered shrubs that do not form contiguous thickets (Cooper 2000; Unitt 2008). The absence of trees at sites is also an important predictor of use by the species (Collier 1994). Grasshopper Sparrows prefer territories with some bare ground but rarely occupy sites with >35% bare ground (Bock and Webb 1984). Additionally, Grasshopper Sparrows may prefer flat sites with a northerly aspect (Gennet et al. 2017). Finally, Grasshopper Sparrows prefer a shallow layer of litter because it provides concealment of nests (Frey et al. 2008; Stauffer et al. 2011; Elliott and Johnson 2017). Grasshopper Sparrows construct their nests on the ground and the structures are usually domed and have overhanging grasses and a side entrance (Vickery 1996). Clutches typically contain four or five eggs (McNair 1987) that are laid as early as May (Vickery 1996). Females are the sole incubators and the incubation period typically lasts 11–13 days (Nicholson 1936; Smith 1968). Nestlings typically fledge about nine days post-hatching and are generally independent by four weeks post-fledging (Vickery 1996) Goals and Objectives 1. Document the distribution and occupancy of Grasshopper Sparrows in the MSHCP-identified Core Areas. a. Conduct repeat-visit point-transect surveys within accessible Grasshopper Sparrow foraging and nesting habitat in the Plan Area, recording all bird species observed. 2. Determine whether Grasshopper Sparrows are successfully reproducing in the MSHCP-identified Core Areas. a. Following detection of singing male Grasshopper Sparrows during surveys, send a team of three biologists to the site to conduct rope- dragging in the vicinity of the detection. If an active nest is detected as a result, we will monitor the nest until it fails or fledges young.

METHODS Survey Design We conducted surveys for Grasshopper Sparrows by making repeat visits (n = 3 visits) to point transects (n = 125 transects; Fig. 1) (Herkert 1994; Best et al. 1997; Reynolds and Krausman 1998; Rahmig et al. 2009; George et al. 2013). We developed survey methods using techniques described in Rosenstock et al. (2002). The design we used allows for the calculation of transect-level detection probability (p) and can also be used to evaluate correlations between covariates (MacKenzie et al. 2006).

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We began study site selection by first selecting Grasshopper Sparrow habitats within our ArcGIS (ESRI 2019) vegetation layer (CDFG et al. 2005) that were identified by the MSHCP (Dudek & Associates 2003) as suitable for the species, namely non- native, valley, and foothill grasslands. We included agricultural land and low-density (≤ 25% coverage) coastal sage scrub as well because we frequently detect Grasshopper Sparrows in or near these habitats. After we identified appropriate sparrow habitat in GIS, we clipped that layer to a separate GIS layer consisting of conserved lands within the Grasshopper Sparrow Core Areas designated by the MSHCP. Next, we generated randomly-located survey points, separated by at least 100 m, within the Core Areas. We scouted each of these points to determine whether the habitat appeared suitable for use by Grasshopper Sparrows. If the habitat was suitable, we generated two more points, each of which was 100 m from the original point; one point was due north and the other was due south of the scouted point (i.e., we had three points in line with each other, creating a point-transect). We chose a spacing of 100 m because it allowed me to place an adequate number of point-transects within smaller Core Areas to allow for data analysis if necessary. We did not have any survey stations in the Steele Peak Core Area in 2019 because it did not contain any conserved land that was suitable for Grasshopper Sparrows. Finally, our 2015 Grasshopper Sparrow survey results suggested that eight survey rounds might be optimal for future efforts. The data also indicated that we should have 31–124 point-transects, assuming we want to accept a 5–10% coefficient of variation in our occupancy estimates (Equation 6.3 in MacKenzie et al. 2006). We ultimately selected point-transects from the ground-truthed sites discussed above and distributed them among the Core Areas in a way that reflected the distribution of apparent Grasshopper Sparrow habitat. Field Methods Grasshopper Sparrow Surveys We scouted potential sites in January and February 2019 and our surveys began on 21 March 2019 and ended on 23 July 2019. We conducted surveys during the first four hours following sunrise (Johnson and Sandercock 2010; McLaughlin et al. 2014) and we terminated surveys if the temperature exceeded 35 °C, during heavy precipitation or fog, or when maximum wind speeds exceeded 20 km/h (Earnst et al. 2009; Jobin and Falardeau 2010; Graves et al. 2010; George et al. 2013; Bogard and Davis 2014; Henderson and Davis 2014; McLaughlin et al. 2014). At the beginning of each point survey, observers recorded the start time, temperature, maximum and average wind speeds during a 1-min period, and sky conditions. Observers spent exactly 5 min at each survey point, during which time they recorded information on their data sheet for all bird species detected. For non-Covered Species, observers recorded information for only the first individual of that species detected, which provided species richness data for the site. For such species, observers recorded the four-letter species code, age class information, and sex. For Covered Species, observers recorded the four-letter species code, age class, and sex for every individual detected while surveying from the point. If observers were unsure whether they had already recorded data on an individual (i.e., they were double-counting), they

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erred on the side of caution and recorded information on that individual. For each Grasshopper Sparrow detected, observers also recorded on their data sheet the distance to the bird. Observers measured distances using a laser rangefinder and distances were never estimated. If a laser rangefinder was unsuitable for measuring the distance, the observer walked to the location of the bird after the 5-min survey period and marked the location using a handheld GPS. We then calculated the distance in the office and recorded it on the data sheet. Finally, we considered any Covered avian species detected outside of survey periods as incidental observations, as were all detections of Covered non-avian species, regardless of when that species was detected. Observers recorded data for these incidental observations on an Incidental Observation datasheet, using the Project Code “Grasshopper Sparrow Surveys.” Nest Surveys If we detected a Grasshopper Sparrow during our surveys, we returned to the site within one week to determine whether there was an active nest. We conducted nest searches using a combination of methods, including rope dragging (Davis 2003; Dieni and Jones 2003; Ruth 2017), behavioral observations (Martin and Geupel 1993), foot flushing, and incidental visual sightings of nests (Ruth 2017). Rope dragging consisted of two biologists dragging a 30-m-long rope, weighted with empty aluminum cans at 1-m intervals, near the detection site. Grasshopper Sparrow territories are generally 0.6–0.9 ha in size (see Ruth 2017 for a summary), so our search area was limited to 1 ha (i.e., a 100 m × 100 m square). A third, and sometimes fourth, biologist followed closely behind the rope to detect flushing birds. Finding a nest via behavioral observations consisted of watching Grasshopper Sparrows until they returned to their nest. This method is typically most successful during the nestling stage, when sparrows are less cryptic returning to their nest (Ruth 2017). When we found a nest, we marked its location using a handheld GPS. We also placed flagging 5 m due north and 5 m due south of the nest, which made it easier for us to find the nest during follow-up visits. We made weekly or semi-weekly visits to each nest until fledging or failure occurred. Habitat Assessment Following our surveys and nest monitoring of Grasshopper Sparrows, we collected habitat assessment data in August and September 2019. We collected data at each survey point from which we detected Grasshopper Sparrows in 2019. Each of these points was assigned a randomly-located point at which we also collected habitat data, hereafter referred to as available sites. Each available point was exactly 100 m from its paired survey point and at least 100 m from any other point at which we collected habitat data. At each point we recorded the elevation, slope, and aspect. We also measured the distance to the nearest tree and calculated the percentage of tree cover within 50 m using ArcGIS (ESRI 2019). Next, we recorded the maximum vegetation height and residual litter/thatch depth 5 m from each point, measured at each of the four cardinal directions. Within 5 m of each point, we counted the number of perennial shrubs taller than the grass canopy, and estimated the percent cover of grass, forbs, and bare ground (Dieni and Jones 2003; Hovick and Miller 2013; Bogard and Davis 2014; Hill and Diefenbach 2014; Small et al. 2015). The survey methods are more completely described in the Western Riverside

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County MSHCP Biological Monitoring Program 2019 Grasshopper Sparrow Survey Protocol. Data Analysis We estimated per-visit (p) and cumulative detection probability (P*) for Grasshopper Sparrows using closed-capture occupancy models (MacKenzie et al. 2006). We considered locations with observations of Grasshopper Sparrows to be used rather than occupied because my survey design may not have met the assumption of population closure (i.e., random movement of animals in and out of sample plots across visits). We used Program MARK (White and Burnham 1999) to construct and compare candidate models that examine site and visit effects on p. We then ranked candidate models according to Akaike’s Information Criterion for small samples (AICc), calculated Akaike weights (wi), and derived weighted-average estimates for p across the entire candidate set unless a single model showed clear support (i.e., wi > 0.9) (Burnham and Anderson 2002). We calculated cumulative detection probability across the three visits using model- averaged estimates of p, and the following formula where pi is the detection probability on a given survey visit:

= 1 3 1 ∗ 𝑃𝑃 − �� − 𝑝𝑝𝑖𝑖� Finally, we calculated variances for P*𝑖𝑖= using1 the delta method (MacKenzie et al. 2006; Powell 2007). For habitat assessment data, we transformed aspect data using a Beers transformation (Beers et al. 1966) before comparing used and available sites. Similarly, we performed an arcsine transformation on percent tree cover within 50 m of points, and percent cover of grass, forbs, and bare ground prior to making comparisons between used and available sites (Zar 1999). Finally, we used a two-sample t-test to compare each variable between used and available sites.

RESULTS Detections of Grasshopper Sparrows We detected 123 avian species during our 2019 surveys, 26 of which are covered by the MSHCP (Appendix A). We detected Grasshopper Sparrows in three large Core Areas in 2019, and all five large Core Areas within the current reporting period (2015– 2019) (Fig. 2), thereby meeting the first requirement of Objective 2 for the species. We did not detect Grasshopper Sparrows within any of the small Core Areas in 2019, nor have we detected them in any of the small Core Areas during the current reporting period (2015–2019) (Fig. 2), thereby failing to meet the second requirement of Objective 2 for the species (Table 1).

Western Riverside County MSHCP 6 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

Western Riverside County MSHCP 7 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

Table 1. The most recent detection of Grasshopper Sparrows within each of the designated Core Areas. The current reporting period is 2015–2019; parenthetical values indicate years preceding the current reporting period. Core Area Most recent Grasshopper Sparrow detection Large Core Areas Badlands/Potrero 2015 Lake Mathews-Estelle Mountain 2019 Lake Skinner/Diamond Valley Lake/Johnson 2019 Ranch Mystic Lake/San Jacinto WA 2015 Santa Rosa Plateau/Tenaja 2019 Small Core Areas Box Springs Never Kabian Park (2005) Prado Basin Never Steele Peak Never Sycamore Canyon (2005)

We have detected Grasshopper Sparrows 738 times on Conserved Land within the Plan Area from 2005 to 2019. Our detections are usually clustered within the Lake Mathews-Estelle Mountain (n = 103 detections), Lake Skinner/Diamond Valley Lake/Johnson Ranch (n = 251), and Santa Rosa Plateau/Tenaja (n = 320) Core Areas. We have a cluster of 12 detections at Oak Mountain, north of Vail Lake (Fig. 2), but we have failed to detect the species here since 2017. Detection Rates and Detection Probability Analysis We conducted three survey rounds in this study. The percentage of surveyed transects along which we detected Grasshopper Sparrows increased from 22% in Round 1 to 39% in Round 2, then decreased slightly to 34% in Round 3. We detected Grasshopper Sparrows along 30 (43%) of our transects in 2019, and most (n = 17 transects, or 57%) of these were in the Santa Rosa Plateau/Tenaja Core Area, followed by the Lake Skinner/Diamond Valley Lake/Johnson Ranch Core Area (n = 10, or 33%). We included in the detection probability analysis the p(t) and p(.) models, which consider variations in detection probability by time (t) and a constant detection probability (.) across time and among groups. We eliminated from analysis the p(g) model, which considers variations in detection probability by group (g), or Core Area, because we had too few Grasshopper Sparrow detections outside of the Santa Rosa Plateau/Tenaja Core Area to justify including the model. We ultimately model-averaged the data because Program MARK did not show strong support for either the p(t) or p(.) models (i.e., wi < 0.9 for both models) (Table 2). These data produced an average detection probability (± SE) of 0.40 (± 0.08) in Round 1, 0.68 (± 0.09) in Round 2, and 0.57 (± 0.08) in Round 3, and an occupancy estimate (ψ) of 0.57. The cumulative detection probability during this same period was 0.92 (± 0.05).

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Table 2. Model rankings for Grasshopper Sparrow surveys in 2019. We modeled variables for detection probabilities (p) to remain constant (.) and vary by time (t) and we modeled occupancy (ψ) to remain constant. Finally, we used Akaike’s Information Criterion corrected for small sample size (AICC) for model selection. a b Model ∆ AICC wi Model likelihood k p(t) ψ(.)c 0.00 0.85 1.00 4 p(.) ψ(.) 3.47 0.15 0.18 2 a AICC weight b Number of parameters c AICC = 222.1286

Grasshopper Sparrow Nesting We documented evidence of successful nesting by Grasshopper Sparrows within three large Core Areas in 2019 (Fig. 3, Table 3), thereby failing to meet the third part of Objective 2 for the species, which requires that five Core Areas support successful reproduction by the species. Further, at least 20 Grasshopper Sparrow pairs must be successfully reproducing within each of the five Core Areas, which we did not document in 2019. We found three Grasshopper Sparrow nests in 2019 and all ultimately failed. Two of the nests were in the Santa Rosa Plateau/Tenaja Core Area and one was in the Lake Mathews-Estelle Mountain Core Area (Fig. 3). In addition, we found at least 18 fledglings in 10 separate locations across three Core Areas (Table 3).

Table 3. Summary of 2019 Grasshopper Sparrow nest counts, and the number of fledglings observed, by Core Area. All nests we found ultimately failed. Core Area n nests detected n fledgling groups n fledglingsa Lake Mathews-Estelle Mountain 1 1 1 Lake Skinner / Diamond Valley 0 4 6 Lake / Johnson Ranch Santa Rosa Plateau / Tenaja 2 5 11 Total 3 10 18 a Minimum number of fledglings seen.

The first nest we found was in the incubation stage on 2 May and contained five eggs, indicating that egg-laying was initiated in late April. The last active nest we found contained three eggs and two nestlings on 20 June. We first detected fledglings on 6 May and the latest fledglings were found by our biologists on 6 June. Habitat Assessment There were not any significant differences between 68 used and 68 available sites with respect to the variables we measured. Sites were most often northeast- or south- facing, although there was not an overall trend toward any one direction (Fig. 4). Points were on gentle slopes and generally contained few trees within 50 m. Maximum vegetation height at used sites was an average of 38.8 cm and residual litter/thatch depth averaged 3.0 cm. Ground cover within 5 m of used sites was most often grass, followed by forbs (Table 4).

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Western Riverside County MSHCP 10 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

No. sites with categorical aspect North 12

10 Northwest Northeast 8

6

4

2

West 0 East

Southwest Southeast

South Figure 4. Frequency of aspects of sites used by Grasshopper Sparrows in 2019. Data did not trend significantly toward any one categorical direction.

Table 4. Grasshopper Sparrow habitat assessment data for 68 used and 68 available sites. Data are presented as mean values (95% CI). Used sites Available sites Elevation (m) 549 (532–566) 547 (530–564) Slope (°) 5.5 (4.5–6.6) 5.4 (4.5–6.3) Distance (m) to nearest tree 182 (146–217) 208 (172–245) Tree cover (%) within 50 m 0.52 (0.03–1.01) 1.31 (0.10–2.52) Maximum vegetation height (cm) 38.8 (35.6–42.0) 37.7 (34.6–40.8) Residual litter/thatch depth (cm) 3.3 (2.9–3.8) 3.0 (2.6–3.4) Within 5 m: No. of perennial shrubs 0.29 (0.13–0.46) 0.28 (0.17–0.39) taller than grass canopy % cover grass 58.0 (52.0–64.0) 57.4 (51.2–63.6) % cover forbs 25.4 (20.8–30.0) 22.6 (18.1–27.1) % cover bare grounda 3.9 (2.3–5.5) 4.7 (2.2–7.2) a Percentages do not total 100% because we oftentimes had ground cover that did not belong to any of our three categories.

DISCUSSION Detections of Grasshopper Sparrows We have detected Grasshopper Sparrows 674 times within the Lake Mathews- Estelle Mountain, Lake Skinner/Diamond Valley Lake/Johnson Ranch, and Santa Rosa

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Plateau/Tenaja Core Areas from 2005 to 2019, accounting for more than 91% of our Grasshopper Sparrow detections during that time. Most of these detections occurred in the Santa Rosa Plateau/Tenaja Core Area, which was identified by Unitt (2008) as being the location in western Riverside County in which the species most consistently occurs. Lake Mathews and Lake Skinner are also identified as sites at which Grasshopper Sparrows occur, albeit irregularly, within western Riverside County (Unitt 2008). Our Grasshopper Sparrow detections in the Santa Rosa Plateau/Tenaja Core Area are scattered throughout the Core Area rather than occurring in clumped groups (Fig. 2). This is likely a reflection of the fact that the tall, dense grassland habitat preferred by Grasshopper Sparrows is relatively well-distributed within the Core Area. Most (91%) of our Grasshopper Sparrow detections in the Lake Mathews-Estelle Mountain Core Area are south of Cajalco Road (Fig. 2), where tall and dense grassland is patchily distributed. Grassland habitat at the sites we surveyed in 2015 was generally too short and sparse to support Grasshopper Sparrows at that time, but habitat surrounding our 2019 survey stations seemed to be slightly more suitable, although we only found two breeding pairs of Grasshopper Sparrows. More than half (53%) of our Grasshopper Sparrow detections within the Lake Skinner/Diamond Valley Lake/Johnson Ranch Core Area are south of Borel Road, specifically within the French Valley WA and Johnson Ranch sites (Fig. 2). Grasses here tend to be tall and dense, with patches averaging 3 ha in size. Contrasting this, we have never detected Grasshopper Sparrows at the adjacent El Sol property in which grasses are kept short for the benefit of species such as Burrowing Owls (Athene cunicularia). Our remaining detections within the Core Area north of Borel Road (i.e., within the Southwestern Riverside Multi-Species Reserve) are generally south and southeast of Lake Skinner, but we have detected Grasshopper Sparrows as far north as Crown Valley, south of Diamond Valley Lake (Fig. 2). We have detected Grasshopper Sparrows just once within the Badlands/Potrero Core Area during the current reporting period. The detection occurred in 2015 in the Norton Younglove Reserve, south of San Timoteo Canyon Road (Fig. 2). Prior to the current reporting period, we detected Grasshopper Sparrows just nine times within the Core Area, from 2005–2011. Areas along San Timoteo Canyon Road and within the Potrero Unit of the San Jacinto WA contain suitable habitat for the species, but much of the rest of the Conserved Land within the Core Area consists of rugged and hilly terrain that is unsuitable for use by the species. We have detected Grasshopper Sparrows nine times within the Mystic Lake/San Jacinto WA Core Area, but only one detection occurred within the current reporting period (Fig. 2). Some of the Conserved Land within the Core Area has the potential to be suitable for the species because there are few trees and the terrain is gently sloping, but much of the area is managed for Stephens’ kangaroo rat (Dipodomys stephensi), whose habitat preferences include open space and sparse vegetative cover (Price et al. 1994), which is not conducive for use by Grasshopper Species (Bock and Webb 1984). In addition, portions of the Core Area are managed for upland game species through agricultural planting, which is not a habitat preferred by Grasshopper Sparrows.

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Our biologists have detected Grasshopper Sparrows twice in the Sycamore Canyon Core Area (Fig. 1). The detections occurred on the same day in 2005 and were 53 m apart, perhaps representing the same individual bird. The northeastern part of the Core Area, where these detections occurred, periodically has tall and dense grasses, but much of the rest of the Core Area is periodically heavily grazed by sheep, so the habitat is usually not conducive to Grasshopper Sparrows (Coppedge et al. 2008). We have detected Grasshopper Sparrows within the remaining Core Areas just once, in 2005, in the Kabian Park Core Area (Fig. 1). This Core Area has just 30 ha of conserved grassland habitat and this is scattered among small patches that average 1.6 ha (range = 0.02–7.6 ha) in size. Patches of this size are generally too small to support Grasshopper Sparrows, which may require patches that are a minimum of 12–100 ha in size (Herkert 1994; Vickery et al. 1994; Walk and Warner 1999). We have never detected Grasshopper Sparrows within the Box Springs, Prado Basin, or Steele Peak Core Areas, as defined in 2019 (Fig. 1). The Prado Basin contains grassland habitat west of Raahauge’s Shooting Range, but we have never detected Grasshopper Sparrows there despite focused survey efforts in 2015 and 2019, and White- tailed Kite (Elanus leucurus) surveys in 2017. One possible explanation for the apparent absence of Grasshopper Sparrows may be that the site has a southerly aspect, which is not usually preferred by the species (Gennet et al. 2017). The Box Springs and Steele Peak Core Areas contain relatively small amounts of conserved grassland habitat (69 ha and 97 ha, respectively). Grassland habitat within these Core Areas is patchily distributed, and as previously discussed, the patches may not be large enough to be conducive to Grasshopper Sparrows (Herkert 1994; Vickery et al. 1994; Walk and Warner 1999). In addition to the designated Core Areas, we have detected Grasshopper Sparrows 12 times in the Oak Mountain area north of Vail Lake (Fig. 2) from 2007 to 2017. We surveyed the area in 2019 but failed to detect any Grasshopper Sparrows. Despite our previous detections of Grasshopper Sparrows at the site, it may not be ideal for the species because of its southerly aspect (Gennet et al. 2017). We recommend continuing to survey transects in this location during future survey efforts because the site may be used as a stopover site for migrating Grasshopper Sparrows. Detection Rates and Detection Probability Analysis Our methods in 2019 resulted in per-visit detection probabilities of 0.40–0.68 and a cumulative detection probability of 0.92 over the course of three survey rounds. This is an increase over what we reported in 2015, when we used line transects to survey for Grasshopper Sparrows (Biological Monitoring Program 2016). Our detection probability values in 2019 more closely resemble what investigators reported in studies in Washington and Delaware, where point counts resulted in cumulative detection probabilities of 0.92 and 0.99, respectively (Earnst and Holmes 2012; Irvin et al. 2013). Surveying from points, rather than while walking line transects, may allow biologists better opportunities to detect singing Grasshopper Sparrows while not having to navigate through dense, dry vegetation, which can easily obscure the sound of a Grasshopper Sparrow singing at even a moderate distance.

Western Riverside County MSHCP 13 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

We observed an increase in detection probability in Round 2 during our 2019 surveys, which occurred from 24 April–11 June. This mirrors a trend that we saw during our 2015 survey effort, when Round 2 detection probabilities increased over Round 1. One potential explanation for this increase is that Grasshopper Sparrows were still migrating to the Plan Area during Round 1, meaning that sites that were occupied in Rounds 2 and 3 were not yet occupied in Round 1. We started our surveys in mid-March with the assumption that Grasshopper Sparrows in southern California are usually territorial by then (Collier 1994); however, some territorial movement can occur through April and May in southern California (Garrett and Dunn 1981). A second explanation is that the singing rate fluctuated throughout the breeding season. Audial detections were almost the exclusive way by which we detected Grasshopper Sparrows, and other investigators have reported that song rate varies throughout the breeding season. For example, the sustained song of the males is used more frequently two to three weeks following territory establishment than during early territory establishment (Smith 1959). This would generally occur in mid- to late March in southern California, assuming territory establishment occurs by early March (Collier 1994) and would have continued into Round 2 of our surveys. Finally, song rates in New England have been documented to diminish in mid-morning beginning in the middle of June (Vickery 1996), which could perhaps explain the relative decrease in detection probabilities during Round 3 of our surveys, which started in mid-June. Site occupancy in our study was 0.57 and the lowest detection probability was 0.40. Using these data and Table 6.1 in MacKenzie et al. (2006), we can conclude that four is the optimal number of visits to survey sites in future Grasshopper Sparrow surveys, assuming we use the same methods as in 2019. We can also conclude that future survey efforts should consist of 39–154 point transects, assuming we want to accept a 5– 10% coefficient of variation for the occupancy estimate (Equation 6.3 in MacKenzie et al. 2006). Grasshopper Sparrow Nesting Searching for Grasshopper Sparrow nests was a time-intensive activity, as indicated by the fact that we found just three nests in 2019. All three nests ultimately failed, but we cannot necessarily draw many conclusions about nest failure rates due to our small sample size. Previous investigations, however, have reported that 35%–53% of Grasshopper Sparrow nests fail (Giocomo et al. 2008; Vos and Ribic 2013), with depredation accounting for 73%–89% of nest failures (Jones et al. 2010; Vos and Ribic 2013). We found the majority (90%) of fledgling groups within the Lake Skinner/Diamond Valley Lake/Johnson Ranch and Santa Rosa Plateau/Tenaja Core Areas, both of which seemed to have large tracts of suitable Grasshopper Sparrow habitat. Within the Lake Mathews-Estelle Mountain Core Area, we only found two breeding pairs, one of which had a failed nest, with the second pair producing at least one fledgling. Grasshopper Sparrows in our study laid eggs beginning in late April, which is at least one month earlier than what is reported for the species by other investigators (Perkins et al. 1998; Giocomo et al. 2008; Jones et al. 2010; Stauffer et al. 2011). Most of

Western Riverside County MSHCP 14 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

these investigations, however, occurred at higher latitudes than our study site, which likely accounts for the earlier dates we observed. Similarly, we first observed fledglings beginning in early May, which is also about a month earlier than what is reported for the species by previous investigators (Vickery 1996; Anthony et al. 2013). Habitat Assessment We did not find any significant differences between used and available sites in 2019 with respect to the variables we measured, or the scale at which we measured those variables. This may reflect homogeneity in our sites with respect to the variables we measured and may further indicate that apparently suitable Grasshopper Sparrow habitat was not patchily distributed within areas where we detected the species. Most of the sites used by Grasshopper Sparrows in our study had a northeasterly or southerly aspect, although there were not any significant trends toward any one categorical direction. Gennet et al. (2017) reported that Grasshopper Sparrows east of the San Francisco Bay in northern California tended to select for sites with northerly aspects, perhaps due to increased soil moisture and reduced solar exposure, both of which may improve habitat conditions for Grasshopper Sparrows. For example, sites with northerly aspects in California tend to contain more native vegetation cover, in part because of these factors, and are thus more likely to be selected for by Grasshopper Sparrows (Gelbard and Harrison 2003). Grasshopper sparrows in our study seemed to prefer sites that were gently sloping, with an average slope of 5.5°. Flat to gently sloping terrain was one of the most important factors influencing Grasshopper Sparrow occupancy in a northern California investigation (Gennet et al. 2017). Grasshopper Sparrows in Montana also appeared to select for nearly flat terrain, selecting sites that had an average slope of 1.4° (Dieni and Jones 2003). While habitat features such as slope and aspect cannot be influenced by management practices, they should be considered when sites are being proposed for use as conservation parcels for Grasshopper Sparrows (Gennet et al. 2017). Tree cover was low within 50 m of sites used by Grasshopper Sparrows in our study, averaging 0.52%. This is similar to tree cover rates reported by Sutter and Ritchison (2005) for a study in central Kentucky, where Grasshopper Sparrows used territories with an average of 0.78% tree cover. Prior investigations have demonstrated that Grasshopper Sparrows tend to prefer sites with relatively little tree cover (Graves et al. 2010; Elliott and Johnson 2017) and may avoid nesting within 75 m of tree cover (Helzer 1996). The preference for sites with little tree cover may be a strategy by Grasshopper Sparrows to reduce nest parasitism by Brown-headed Cowbirds (Molotrhus ater) (Delisle and Savidge 1996), which should be taken into consideration when sites are being conserved for Grasshopper Sparrows. The maximum vegetation height at sites used by Grasshopper Sparrows in our study ( = 38.8 cm) is within the range for the species reported by previous investigators, which is 23.6–69 cm (Dieni and Jones 2003; Hill and Diefenbach 2014). Similarly, the residual𝑥𝑥 ̅ litter/thatch depths at our sites ( = 3.3 cm) is within the range reported for the species, which is 2.4–9.4 cm (Whitmore 1981; Dieni and Jones 2003). Sites conserved for Grasshopper Sparrows should approximate𝑥𝑥̅ these vegetation heights and litter depths

Western Riverside County MSHCP 15 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

through prescribed burns or livestock grazing (see Recommendations – Conservation and Management, below). Ground cover at our sites was dominated by grasses ( = 58.0% within 5 m), followed by forbs or herbaceous cover ( = 25.4%). Prior investigations have revealed similar trends at sites used by Grasshopper Sparrows, where grass𝑥𝑥̅ cover dominates, at 56.2–72%, and herbaceous cover is 21–25%𝑥𝑥̅ (Whitmore 1981; Bock and Webb 1984; Dieni and Jones 2003; Hill and Diefenbach 2014). Bare ground coverage at our sites averaged 3.9% and is somewhat variable in previous investigations, ranging from 0.4– 23% (Bock and Webb 1984; Dieni and Jones 2003). These results support the conclusions of prior investigators, who have stated that Grasshopper Sparrows seem to prefer sites with heterogeneity in the vegetation structure (Gennet et al. 2017), which consists of a mosaic of grasses and herbaceous cover (Holcomb et al. 2014). The benefits of such heterogeneity may also be important for the survival of fledgling Grasshopper Sparrows (Small et al. 2015), who must transition from using areas of high grass cover while still dependent upon parents for food, to areas with more bare ground cover when independent and feeding themselves. Recommendations Future Surveys The results of our 2019 surveys indicate that surveying for Grasshopper Sparrows using a point transect method produces higher detection probabilities than line transects, which we used in our 2015 surveys. Subsequent survey efforts should thus continue to employ point transect methods. Further, four survey rounds may be sufficient, and we may want to use a removal sampling design for future surveys to use our time more efficiently (MacKenzie et al. 2006). Future survey efforts should not underestimate the amount of time required to find Grasshopper Sparrow nests and fledglings. The rope dragging method for nest searching requires three or four biologists and may result in finding just one nest for 20–25 person- hours. Similarly, finding fledglings requires time-consuming observational methods and may be equally as productive as rope dragging for nests. Finally, we should continue to collect habitat data at sites used by Grasshopper Sparrows. If sample sizes warrant, we should also collect data at nest sites. We may want to consider collecting habitat data at larger radii around used sites, perhaps 10 m or 25 m, to better capture variations in the habitat structure. Conservation and Management Prescribed burns, grazing, mowing, or some combination thereof are common management techniques at sites that contain Grasshopper Sparrows. Such techniques should ideally occur early in the year to avoid causing decreases in Grasshopper Sparrow abundance or return rates (Ingold et al. 2010; Johnson and Sandercock 2010). Because Grasshopper Sparrows prefer a shallow litter layer for nest concealment (Frey et al. 2008; Stauffer et al. 2011), any management technique for sparrows should retain this habitat feature as much as possible, especially during the breeding season. When the litter layer is removed, Grasshopper Sparrows tend to abandon the site. For example, Grasshopper

Western Riverside County MSHCP 16 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

Sparrows avoided burned plots in a southeastern Arizona study site for two years following prescribed burns, largely due to the loss of the litter layer (Bock and Bock 1992). Similarly, Grasshopper Sparrow abundance decreased following a wildfire in Washington, but increased in the third and fourth years following the fire (Earnst et al. 2009). These trends were also reported from a site in Texas, where the relative abundance of Grasshopper Sparrows decreased following a prescribed fire, but eventually increased as vegetation regrowth progressed (Reynolds and Krausman 1998). Grazing and prescribed burns can be used by managers to create similar conditions that are preferred by Grasshopper Sparrows, but the suitability of each application may depend upon the site conditions. For example, western Grasshopper Sparrows tend to prefer sites with native bunchgrass (Earnst and Holmes 2012), which contains the patches of bare ground preferred by the species. In these sites, light to moderate grazing may suffice because fire may create too much open space. Conversely, fires may be ideally suited for sites with dense grasses because they will create openings in the habitat for Grasshopper Sparrows (Earnst et al. 2009). Another benefit of light to moderate grazing is that it is comparable to entire sites being burned annually. The conditions created by such treatments are preferred by the species over the more extreme conditions created by patch-burn treatments in which litter and vegetation are allowed to accumulate before being completely removed by fire (Coppedge et al. 2008). Grazing and prescribed fire do not always benefit Grasshopper Sparrows in the same way, however. Grasshopper Sparrow abundance and density may be higher in grazed sites, whereas nest success tends to be highest in burned hayfields (Rahmig et al. 2008; Powell and Bisby 2013). More investigation may be needed at the local scale to determine when to apply each treatment to Grasshopper Sparrow management and conservation. Finally, any management technique for improving Grasshopper Sparrow habitat should seek to create a diverse grassland ecosystem that contains a patchwork of bare ground, litter, shrubs, and dense grasses and forbs. This kind of patchwork may encourage use by adult Grasshopper Sparrows but may also be critically important for juvenile sparrows. Dependent juvenile Grasshopper Sparrows tend to benefit from patches containing high levels of vegetative cover, in which they can hide from predators, whereas independent juveniles must feed themselves and thus benefit from areas that contain bare ground in which they can forage (Small et al. 2015).

ACKNOWLEDGEMENTS 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. 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 in 2019 were Masanori Abe, Jennifer Hoffman, Cristina Juran, Nicholas Peterson, and Nathan Pinckard. Additional Program staff who assisted with habitat assessment data collection were Andrea Campanella, Collin Farmer, Tara Graham, Robert Packard, Esperanza Sandoval, and Taylor Zagelbaum. Finally, Eliza Perez volunteered with us to help collect habitat assessment data.

Western Riverside County MSHCP 17 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

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Grinnell J, Miller AH. 1944. The distribution of the birds of California. Pacific Coast Avifauna 27. Helzer CJ. 1996. The effects of wet meadow fragmentation on grassland birds. Master’s thesis, University of Nebraska, Lincoln. Henderson AE, Davis SK. 2014. Rangeland health assessment: A useful tool for linking range management and grassland bird conservation? Rangeland Ecology and Management 67:88–98. Herkert JR. 1994. The effects of habitat fragmentation on Midwestern grassland bird communities. Ecological Applications 4:461–471. Hill JM, Diefenbach DR. 2014. Occupancy patterns of regionally declining grassland sparrow populations in a forested Pennsylvania landscape. Conservation Biology 28:735–744. Holcomb ED, Davis CA, Fuhlendorf SD. 2014. Patch-burn management: Implications for conservation of avian communities in fire-dependent sagebrush ecosystems. Journal of Wildlife Management 78:848–856. Hovick TJ, Miller JR. 2013. Broad-scale heterogeneity influences nest selection by Brown-headed Cowbirds. Landscape Ecology 28:1493–1503. Ingold DJ, Dooley JL, Cavender N. 2010. Nest-site fidelity in grassland birds on mowed versus unmowed areas on a reclaimed surface mine. Northeastern Naturalist 17:125–134. Irvin E, Duren KR, Buler JJ, Jones W, Gonzon AT, Williams CK. 2013. A multi-scale occupancy model for the Grasshopper Sparrow in the Mid-Atlantic. Journal of Wildlife Management 77:1564–1571. Jobin B, Falardeau G. 2010. Habitat associations of Grasshopper Sparrows in southern Québec. Northeastern Naturalist 17:135–146. Johnson TN, Sandercock BK. 2010. Restoring tallgrass prairie and grassland bird populations in tall fescue pastures with winter grazing. Rangeland Ecology and Management 63:679–688. Jones SL, Dieni JS, Gouse PJ. 2010. Reproductive biology of a grassland songbird community in northcentral Montana. Wilson Journal of Ornithology 122:455– 464. MacKenzie DI, Nichols JD, Royle JA, Pollack KH, Bailey LL, Hines, JE. 2006. Occupancy estimation and modeling: Inferring patterns and dynamics of species occurrence. Elseiver, London. Martin TE, Geupel GR. 1993. Nest-monitoring plots: Methods for locating nests and monitoring success. Journal of Field Ornithology 64:507–519. McCaskie G, DeBenedictis P, Erickson R, Morlan J. 1979. Birds of Northern California: An Annotated Field List, 2nd edition. Golden State Audubon Society, Berkeley, California.

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McLaughlin ME, Janousek WM, McCarty JP, Wolfenbarger LL. 2014. Effects of urbanization on site occupancy and density of grassland birds in tallgrass prairie fragments. Journal of Field Ornithology 85:258–273. McNair DB. 1987. Egg data slips – Are they useful for information on egg-laying dates and clutch size. Condor 89:369–376. Nicholson WH. 1936. Notes on the habits of the Florida Grasshopper Sparrow. Auk 53:318–319. Perkins DW, Vickery PD, Dean TF, Scheuerell MD. 1998. Florida Grasshopper Sparrow reproductive success based on nesting records. Florida Field Naturalist 26:7–17. Powell AFLA, Busby WH. 2013. Effects of grassland management on breeding birds at the western edge of the tallgrass prairie ecosystem in Kansas. Natural Areas Journal 33:130–138. Powell LA. 2007. Approximating variance of demographic parameters using the delta method: A reference for avian biologists. Condor 109:949–954. Price MV, Goldingay RL, Szychowski LS, Waser NM. 1994. Managing habitat for the endangered Stephens’ kangaroo rat (Dipodomys stephensi): Effects of shrub removal. American Midland Naturalist 131:9–16. Rahmig CJ, Jensen WE, With KA. 2009. Grassland bird response to land management in the largest remaining tallgrass prairie. Conservation Biology 23:420–432. Reynolds MC, Krausman PR. 1998. Effects of winter burning on birds in mesquite grassland. Wildlife Society Bulletin 26:467–476. Rosenstock SS, Anderson DR, Giesen KM, Leukering T, Carter MF. 2002. Landbird counting techniques: Current practices and an alternative. Auk 119:46–53. Ruth JM. 2017. Life history attributes of Arizona Grasshopper Sparrow (Ammodramus savannarum ammolegus) and comparisons with other North American subspecies. American Midland Naturalist 178:64–81. Small DM, Blank PJ, Lohr B. 2015. Habitat use and movement patterns by dependent and independent juvenile Grasshopper Sparrows during the post-fledging period. Journal of Field Ornithology 86:17–26. Smith RL. 1959. The songs of the Grasshopper Sparrow. Wilson Bulletin 71:141–152. Smith RL. 1968. Grasshopper Sparrow. Pages 725–745 in Austin OL, Jr., editor. Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows, and allies, Part 2. U.S. National Museum Bulletin 237. Stauffer GE, Diefenbach DR, Marshall MR, Brauning DW. 2011. Nest success of grassland sparrows on reclaimed surface mines. Journal of Wildlife Management 75:548–557. Sutter B, Ritchison G. 2005. Effects of grazing on vegetation structure, prey availability, and reproductive success of Grasshopper Sparrows. Journal of Field Ornithology 76:345–351.

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Unitt P. 2008. Grasshopper Sparrow (Ammodramus savannarum). Pages 393–399 in Shuford WD and Gardali T, 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, California, and California Department of Fish and Game, Sacramento. Vickery PD. 1996. Grasshopper Sparrow (Ammodramus savannarum). In Poole AF, Gill FB, editors. The Birds of North America Online. Cornell Lab of Ornithology, Ithaca, New York. Available from https://doi.org/10.2173/bna.239 (accessed October 2019). Vickery PD, Jr., Hunter ML, Melvin SM. 1994. Effects of habitat area on the distribution of grassland birds of Maine. Conservation Biology 8:1087–1097. Vos SM, Ribic CA. 2013. Nesting success of grassland birds in oak barrens and dry prairies in west central Wisconsin. Northeastern Naturalist 20:131–142. Walk JW, Warner RE. 1999. Effects of habitat area on the occurrence of grassland birds in Illinois. American Midland Naturalist 141:339–344. White GC, Burnham KP. 1999. Program MARK: Survival estimation for populations of marked animals. Bird Study 46 Supplement: 120–138. Downloaded August 2009. Whitmore RC. 1981. Structural characteristics of Grasshopper Sparrow habitat. Journal of Wildlife Management 45:811–814. Zar JH. 1999. Biostatistical Analysis. 4th edition. Prentice Hall, Upper Saddle River, New Jersey.

Western Riverside County MSHCP 22 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

Appendix A. Avian species detected during 2019 Grasshopper Sparrow surveys. Species in bold are covered by the MSHCP.

COMMON NAME SCIENTIFIC NAME Acorn Woodpecker Melanerpes formicivorus American Avocet Recurvirostra americana American Coot Fulica americana American Crow Corvus brachyrhynchos American Goldfinch Spinus tristis American Kestrel Falco sparverius American Pipit Anthus rubescens American White Pelican Pelecanus erythrorhynchos American Wigeon Mareca americana American Yellow Warbler Setophaga petechia brewsteri Anna's Hummingbird Calypte anna Ash-throated Flycatcher Myiarchus cinerascens Bald Eagle Haliaeetus leucocephalus Band-tailed Pigeon Patagioenas fasciata Barn Swallow Hirundo rustica Bell's Sparrow Artemisiospiza belli Bewick's Wren Thryomanes bewickii Black Phoebe Sayornis nigricans Black-chinned Hummingbird Archilochus alexandri Black-chinned Sparrow Spizella atrogularis Black-headed Grosbeak Pheucticus melanocephalus Black-necked Stilt Himantopus himantopus Blue Grosbeak Passerina caerulea Blue-gray Gnatcatcher Polioptila caerulea Brewer's Blackbird Euphagus cyanocephalus Brewer's Sparrow Spizella breweri Bullock's Oriole Icterus bullockii Bushtit Psaltriparus minimus California Horned Lark Eremophila alpestris actia California Quail Callipepla californica California Scrub-Jay Aphelocoma californica California Thrasher Toxostoma redivivum California Towhee Melozone crissalis Canyon Wren Catherpes mexicanus Caspian Tern Hydroprogne caspia Cassin's Kingbird Tyrannus vociferans Cedar Waxwing Bombycilla cedrorum Cinnamon Teal Spatula cyanoptera Clark’s Grebe Aechmophorus clarkii Cliff Swallow Petrochelidon pyrrhonota Coastal California Gnatcatcher Polioptila californica californica Common Raven Corvus corax Common Yellowthroat Geothlypis trichas Cooper's Hawk Accipiter cooperii

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Appendix. Continued.

COMMON NAME SCIENTIFIC NAME Costa's Hummingbird Calypte costae Double-crested Cormorant Phalacrocorax auritus Downy Woodpecker Dryobates pubescens Eared Grebe Podiceps nigricollis Eurasian Collared-Dove Streptopelia decaocto European Starling Sturnus vulgaris Fox Sparrow Passerella iliaca Gadwall Mareca strepera Golden Eagle Aquila chrysaetos Grasshopper Sparrow Ammodramus savannarum Great Blue Heron Ardea herodias Great Egret Ardea alba Greater Roadrunner Geococcyx californianus Greater Yellowlegs Tringa melanoleuca Great-tailed Grackle Quiscalus mexicanus House Finch Haemorhous mexicanus House Sparrow Passer domesticus House Wren Troglodytes aedon Killdeer Charadrius vociferus Lark Sparrow Chondestes grammacus Lawrence's Goldfinch Spinus lawrencei Lazuli Bunting Passerina amoena Least Bell's Vireo Vireo bellii pusillus Lesser Goldfinch Spinus psaltria Lesser Scaup Aythya affinis Loggerhead Shrike Lanius ludovicianus Long-billed Dowitcher Limnodromus scolopaceus Mallard Anas platyrhynchos Merlin Falco columbarius Mountain Quail Oreortyx pictus Mourning Dove Zenaida macroura Northern Flicker Colaptes auratus Northern Harrier Circus hudsonius Northern Mockingbird Mimus polyglottos Northern Pintail Anas acuta Northern Rough-winged Swallow Stelgidopteryx serripennis Northern Shoveler Spatula clypeata Nuttall's Woodpecker Dryobates nuttallii Oak Titmouse Baeolophus inornatus Orange-crowned Warbler Leiothlypis celata Osprey Pandion haliaetus Pacific-slope Flycatcher Empidonax difficilis Phainopepla Phainopepla nitens Pied-billed Grebe Podilymbus podiceps Prairie Falcon Falco mexicanus

Western Riverside County MSHCP 24 Biological Monitoring Program 2019 Grasshopper Sparrow Survey and Nest Monitoring Report

Appendix. Continued.

COMMON NAME SCIENTIFIC NAME Red-shouldered Hawk Buteo lineatus Red-tailed Hawk Buteo jamaicensis Red-winged Blackbird Agelaius phoeniceus Ring-necked Duck Aythya collaris Rock Pigeon Columba livia Rock Wren Salpinctes obsoletus Ruddy Duck Oxyura jamaicensis Savannah Sparrow Passerculus sandwichensis Say's Phoebe Sayornis saya Short-eared Owl Asio flammeus Snowy Egret Egretta thula Song Sparrow Melospiza melodia Southern California Rufous- Aimophila ruficeps canescens crowned Sparrow Spotted Towhee Pipilo maculatus Swainson's Hawk Buteo swainsoni Tree Swallow Tachycineta bicolor Turkey Vulture Cathartes aura Vermilion Flycatcher Pyrocephalus rubinus Vesper Sparrow Pooecetes gramineus Violet-green Swallow Tachycineta thalassina Western Bluebird Sialia mexicana Western Grebe Aechmophorus occidentalis Western Kingbird Tyrannus verticalis Western Meadowlark Sturnella neglecta Western Wood-Pewee Contopus sordidulus White-breasted Nuthatch Sitta carolinensis White-crowned Sparrow Zonotrichia leucophrys White-faced Ibis Plegadis chihi White-tailed Kite Elanus leucurus White-throated Swift Aeronautes saxatalis Wilson's Warbler Cardellina pusilla Wrentit Chamaea fasciata Yellow-breasted Chat Icteria virens Yellow-rumped Warbler Setophaga coronata

Western Riverside County MSHCP 25 Biological Monitoring Program