Landbird Monitoring in One Tam 2018 and 2019

Final Report to the Golden Gate National Parks Conservancy December 2019

Ryan DiGaudio1 and Diana Humple2, Point Blue Conservation Science, 3820 Cypress Drive #11, CA, 94954; 1ph: (415) 868-0655 ext. 408; [email protected]; 2ph: (415) 868-0655 ext. 386; [email protected]

TABLE OF CONTENTS

EXECUTIVE SUMMARY ...... 1 INTRODUCTION ...... 2 Landbird Monitoring History within One Tam ...... 3 METHODS ...... 4 Field Methods ...... 4 Study Area ...... 5 Site Selection ...... 8 Revisited Historic Sites (Mixed Habitats): ...... 8 Continuous Long-Term Sites (Mixed Habitats) ...... 9 New Sites (Grassland) ...... 9 Statistical Analysis ...... 11 Assessing Coverage and Habitat for One Tam Landbird Monitoring ...... 13 RESULTS ...... 13 Bird Species Composition ...... 13 New Grassland Sites vs. Historic Revisited and Continuously Monitored Sites ...... 14 Habitat Coverage Assessment ...... 18 DISCUSSION ...... 19 Grasslands ...... 19 Historic Revisited Points in Mixed Habitats ...... 22 Habitat Coverage Assessment ...... 23 MONITORING RECOMMENDATIONS ...... 24 Grassland Bird Monitoring Recommendations ...... 25 Mixed Habitat Bird Monitoring Recommendations...... 27 Recommendations & Considerations for the Overall Landbird Monitoring Program ...... 28 ACKNOWLEDGMENTS ...... 30 LITERATURE CITED ...... 31

EXECUTIVE SUMMARY This study represents the execution of the actionable item recommended in the bird component of the One Tam report on Mt. Tamalpais natural resources (Gardali et al. 2016): to expand existing landbird monitoring within the One Tam region to additional jurisdictions to better assess the health of the avian community on a mountain-wide scale; and to give special attention to grassland habitat. This was accomplished through the addition of 88 new point count survey locations (points) in grassland habitat in Golden Gate National Recreation Area, Mt. Tamalpais State Park, Marin Municipal Water District lands, and French Ranch and Roy’s Redwoods open space reserves; plus revisiting 102 historic points across most of these jurisdictions on lands that had not been surveyed in at least the last decade, and which included points in coastal scrub, a habitat also identified in the One Tam report as lacking in long- term bird data for the region (Gardali et al. 2016). These new grassland points and historic revisited points were surveyed in 2018 and 2019. Additionally, in 2019, 336 continuously monitored points were also surveyed, which were predominantly on Marin Municipal Water District lands. We summarize this effort and the results herein. For the grassland portion of the study, we detected grassland specialists only in the new grassland points, with a concentration on the northwestern corner of the One Tam region, in Golden Gate National Recreation Area. By combining the new grassland, revisited historic, and continuously monitored points, we surveyed 551 points, and achieved coverage of the dominant habitat types approaching the proportions in which those habitats occurred in the One Tam region. Finally, we provide recommendations and considerations for future monitoring that will allow land managers to track the status of the landbird community in the One Tam region.

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INTRODUCTION

The lands of Mt. Tamalpais in Marin County are managed by multiple agencies, and recently, a non- jurisdictional approach was adopted by the land managers, partners, and the One Tam consortium, to provide more effective management and understanding of the comprehensive Tamalpais ecosystem (Edson 2016). The One Tam “Peak Health” report recommends the expansion of existing bird monitoring efforts within the One Tam area of focus (hereafter referred to as the One Tam region) to improve our ability to confidently assess trends in health of the region’s bird populations on a “mountain-wide scale, regardless of jurisdictional differences regarding approaches to vegetation management or recreational access” (Gardali et al. 2016). It is appropriate for this expanded effort to build upon the existing long- term bird monitoring program on Marin Municipal Water District (MMWD) lands to include surveys at lands managed by the other major land managers within the One Tam region; these include the National Park Service (NPS), California State Park (CSP), and Marin County Parks (MCP). Furthermore, the Peak Health report calls for increased bird monitoring coverage of grassland habitat, since the status and trends of grassland birds in the One Tam region was determined to be unknown (Gardali et al. 2016).

With the exception of One Tam’s grassland birds, the condition and trends of bird communities in other terrestrial habitats are considered good and stable with a high degree of confidence (Gardali et al. 2016). Over the past two decades, Point Blue Conservation Science (hereafter Point Blue), in partnership with multiple agencies in Marin County, have conducted landbird surveys as part of inventory or monitoring efforts within the One Tam region in various habitat types including multiple forest types, coastal scrub, chaparral, and riparian, with an emphasis on MMWD lands (Gardali et al. 2010a, Cormier et al. 2014, Gardali et al. 2016, Dettling and Humple 2017).

Despite the ongoing long-term landbird studies, the condition and trends of the One Tam region’s grassland bird community has been unknown because grassland habitat was not adequately sampled in preexisting monitoring efforts, which focused on mixed habitats across MMWD lands (Cormier et al. 2014) and riparian habitat (Gardali et al. 2010a). The need to fill this information gap is especially critical since grassland birds are experiencing more rapid population declines than any other group of birds in North America (Peterjohn and Sauer 1999, Sauer et al. 2008, Vickery and Helkert 2001, Brennan and Kuvlesky 2005, Rosenberg et al. 2019). Having a thorough assessment of One Tam’s grassland birds, and establishing long-term monitoring to determine trends, are necessary to identify what, if any, conservation or management actions might be warranted to benefit the region’s grassland bird population. Furthermore, having a better understanding of how these lands contribute to regional grassland bird populations could inform broader conservation approaches to grassland birds in general. As such, Point Blue, in partnership with One Tam agencies and the Golden Gate National Parks Conservancy (GGNPC), implemented additional landbird monitoring in 2018 and 2019 to cover the majority of the One Tam region’s grassland habitat.

To further increase the scope and confidence of our ability to assess landbird population trends within the One Tam region across mixed habitats, in 2018 and 2019 Point Blue, in addition to surveying our continuously monitored bird survey transects, also revisited historic bird survey transects (in mixed

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habitats) that had not been surveyed in the past two decades. This was done because, for roughly the past 20 years, most continuous long-term bird monitoring sites in the One Tam region had been limited to MMWD lands (with the exception of one riparian transect, Redwood Creek, which is on both NPS and CSP). Expanding the scope of monitoring beyond MMWD lands is important, because to limit monitoring to lands managed by a single agency may not be representative of this region, particularly with NPS managing a significant portion of the remaining One Tam region, and the jurisdictions occurring in different geographies (e.g., with coastal scrub being poorly represented in MMWD given its geography). The historic revisited survey transects in mixed habitats were predominantly on NPS lands, with some on CSP, MCP, and private lands. Additionally, the existence of these pre-existing survey transects provided an opportunity to expand the monitoring footprint without needing to establish new study sites, thus allowing us to assess landbird trends over a longer period by using historic points than if we established new sites in 2018.

In this report, we present results from the One Tam landbird monitoring efforts conducted by Point Blue in 2018 and 2019, with an emphasis on One Tam’s grassland birds. We then use these results to offer recommendations for a modified long-term monitoring program for One Tam landbirds that better represents the jurisdictions, habitats (including grasslands), and geographies that may not have been as well sampled in the previous monitoring regime. We do not provide trend data in this report, nor report in depth on the standard landbird monitoring that took place on MMWD land in 2019, which is being reported on separately (Cormier et al. in prep). Specifically, we:

(1) summarize results for grassland focal species and compare between the newly established grassland survey sites and pre-existing sites (consisting of historic revisited sites, and continuously monitored sites representing mixed habitats, including some grasslands);

(2) assess the survey coverage of the major habitat types within the One Tam region, based on the dominant habitat type represented around each survey point; and

(3) based on our findings, provide future monitoring recommendations to improve the scope and confidence in assessing landbird community conditions and trends within the One Tam region, for the continued monitoring of grassland birds as well as landbirds across all major habitats.

Landbird Monitoring History within One Tam

Landbird monitoring in the One Tam region includes a combination of continuous, long-term monitoring efforts; intermittent inventory and monitoring efforts; single-species studies; and some site-specific management studies. Additional bird monitoring efforts conducted by Point Blue Conservation Science within the One Tam region during the 2018-19 One Tam monitoring effort that are not otherwise discussed in this report include: (1) Northern Spotted Owl monitoring (Cormier and Duncan 2018), which has been conducted annually since 1997; (2) nesting-bird surveys prior to vegetation management on MMWD lands (Point Blue unpubl. data); (3) the establishment of coastal Marbled Murrelet surveys at Muir Beach, whose monitoring was predominantly conducted by NPS and GGNPC biologists; and (4) constant effort mist-netting at Redwood Creek (Gardali et al. 2010a).

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Three types of survey efforts, all involving point count surveys, are included in this report and contributed to the larger One Tam landbird monitoring study in 2018-19.

The first type of survey effort included in this One Tam study includes two existing continuous long-term monitoring programs, although they were not specifically funded for the purposes outlined in our scope of work for GGNPC for this One Tam study. The first program is the long-term monitoring across mixed habitats that has been conducted at point count transects on MMWD lands since 1996, is currently surveyed every three years, and is funded by MMWD (Cormier et al. 2014, Cormier and Humple 2017); more details related to this program in 2019 will be reported on separately (Cormier et al. in prep). The second program is the long-term monitoring in riparian habitat at Redwood Creek in Mount Tamalpais State Park and Golden Gate National Recreation Area, from Muir Woods to Muir Beach. These points have been surveyed annually since 1997, and has been funded by a combination of NPS, individual donors to the Palomarin Field Station, and, in 2019, by GGNPC. Surveys are conducted annually at Redwood Creek because it is one of Point Blue’s Palomarin Field Station long-term core study sites in the region where additional, intensive monitoring also takes place. Redwood Creek is also part of a larger network of study sites Point Blue surveys as part of the NPS Inventory & Monitoring (I&M) effort for riparian landbirds in the San Francisco Bay Area Network (Gardali et al. 2010a).

The second type of survey effort included in this report include various historic study sites that were revisited in 2018-19 specifically for this One Tam study. One historic transect, located at French Ranch Open Space Preserve and previously surveyed in 2009, was resurveyed in 2019 in order to contribute to the One Tam effort, although this was funded through a separate agreement with Marin County Parks. The remaining historic sites, which were resurveyed in 2018, were initially established as part of earlier NPS inventory and monitoring programs, and have not been surveyed in 18-20 years.

The third type of survey effort that was part of this One Tam study was a set of newly established grassland study sites surveyed in 2018-19.

See the Site Selection section below for details of how each of the above were initially established.

METHODS

Field Methods

Standardized point count surveys (Ralph et al. 1993) were used to assess landbird abundance and community composition in the One Tam region. All point count surveys were conducted in 2018 and 2019 by experienced Point Blue field biologists with extensive knowledge of the songs and calls of birds in coastal California. Point count stations were organized by transect, where each transect took 1-2 mornings to completely survey. All points were surveyed two times during peak breeding season, as is consistent with other concurrent monitoring efforts in the region. The first round of surveys occurred in May and the second round occurred in June. When possible, the order in which survey points were visited within a transect were reversed or altered on the second visit. Surveys began 15 minutes after local sunrise and concluded within 4 hours of sunrise. All birds seen or heard at each point were

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recorded during a 5-minute sampling period, in which each bird detection was classified according to the type of detection (visual, song or call). For all species, each individual bird was recorded as a separate observation. Point count data were collected using the Variable Circular Plot (VCP) point count method, which can incorporate a measure of detectability into population estimates. Distances to each bird were estimated in the following bands: 0-10m, 10-20m, 20-30m, 30-50m, 50-100m, and > 100 (observers used laser range-finders to help determine distances). Counts were not conducted during rainy, excessively foggy, or windy conditions, where bird activity levels or detection probability was reduced. Data forms, metadata, databases, and data entry and proofing programs can be found at http://data.prbo.org/cadc2/index.php?page=songbird-point-counts; data are password protected but can be made accessible upon request.

Study Area

The One Tam region is approximately 52,744 acres, and most of its area is managed by MMWD, NPS, California State Parks (CSP), and Marin County Parks (MCP), along with some private and municipal lands (Figure 1). Altogether, 551 point count stations (hereafter ‘points’) across 45 transects were surveyed within the One Tam region during the breeding seasons in 2018 and 2019 (Figure 1). This included 88 new grassland points that were established and surveyed in 2018-19, with 44 of these new grassland points on NPS land, 13 on CSP land, 25 on MMWD land, and 6 on MPC land (Tables 1 and 2). An additional 102 historic points in mixed-habitat types were re-surveyed in 2018-19 (hereafter ‘historic revisited’ points), where 68 were on NPS lands, 15 on CSP land, 8 on MCP land, and 11 on private lands (Table 1 and 3). The remaining 361 points were surveyed as part of preexisting long-term monitoring projects within the One Tam region (hereafter ‘continuously monitored’ points); 337 points are monitored as part of a long-term MMWD landbird monitoring program, with a minority of those points located on adjacent lands not managed by MMWD (see Cormier et al. 2014 for more details). One continuously monitored transect, Redwood Creek, which includes points on both NPS and CSP lands, is monitored as part of the NPS Riparian Landbird I&M program (Gardali et al. 2010a). Complete narratives for all but the continuously monitored MMWD transects, as well as the pre-existing transects to which new grassland points were added in 2018-19, are included in Supplement A (available upon request); narratives for the remaining MMWD transects are maintained at Point Blue’s Palomarin Field Station and can be made available upon request.

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Table 1. The number of new and historic avian point count stations that were surveyed by Point Blue in 2018-19 in the One Tam region, broken down by land manager and year surveyed (note that MCP and continuously monitored points were funded through different efforts – see text for details). Tables 2 and 3 provide further details of new grassland and historic revisited points. New New Historic Historic Continuously Grassland Grassland Revisited Revisited Monitored

(2018) (2019) (2018) (2019) (2019)1 Total MCP 6 8 13 27 MMWD 25 295 320 NPS 44 68 27 139 CSP 13 15 25 53 Private 11 1 12 Total Points 57 31 94 8 361 551 1 the 24 Redwood Creek points (on NPS and CSP lands) were also monitored in 2018 but to keep consistent, only one year of monitoring (the same as for the other continuously monitored transects) is included in this report

Table 2. New grassland point count stations established as part of new transects or added to existing transects within the One Tam region that were surveyed by Point Blue in 2018-19. Transect Code Land Manager Points Year Surveyed New Transects Borello / Highway 1 BORE NPS 7 2018 Northwest Corner of One Tam NWCO NPS 9 2018 Rancho Baulines / Dogtown RABA NPS 9 2018 Ragetti / Highway 1 RAGE NPS 10 2018 West of Shafter Grade Trail WESG NPS 9 2018 Coastal Trail / South of Ridgecrest CTRI CSP 13 2018 Bathtub Trail BATH MMWD 3 2019 Blue Ridge Fire Road BLUE MMWD 4 2019 Worn Springs Road WSRO MMWD 6 2019 New Points within Pre-existing Transects Hidden Cove HICO MMWD 1 2019 Lakeview Road LAVR MMWD 1 2019 Oat Hill Road OHFR MMWD 1 2019 Pine Mountain Road PIMR MMWD 3 2019 Ridgecrest Boulevard RICR MMWD 6 2019 French Ranch / Roy's Redwoods FRRA MCP 6 2019 Total New Grassland Points: 88

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Figure 1. Point Blue point count stations surveyed in 2018-19 within the One Tam region, with the extent of grassland habitat shown in green, new grassland points in yellow (transect codes in black), historic revisited points in mixed habitats in red (transect codes in red), and continuously monitored points in blue (transects not labeled).

Table 3. Historic revisited point count transects in mixed habitats within the One Tam region that were re-surveyed by Point Blue in 2018-19. Transect Code Land Manager Points Years Surveyed Ben Johnson Trail BJTR NPS 15 1997, 1998, 1999, 2018 Bootjack Trail BOTR CSP 15 1997, 1998, 1999, 2018 Eucalyptus Mill Valley EUMV NPS 9 2000, 2018 McCurdy Trail MCTR NPS 6 1999, 2018 Morse's Gulch MOGU NPS and Private 15 1997, 1998, 2018 Muir Woods Off Trail MWOT NPS 15 1997, 1998, 1999, 2018 Randall Trail RATR NPS 8 2000, 2018 Stinson Gulch STGU NPS 11 1997, 1998, 2018 French Ranch1 FRRA MCP and Private 8 2009, 2019 Total Historic Mixed-habitat Points: 102 1 also had new points added in 2019 (see Table 2)

Site Selection

Revisited Historic Sites (Mixed Habitats): Historic points in mixed habitats (Table 3) included those originally surveyed in 1998, 1999, or 2001 as part of Point Blue (then PRBO) landbird inventory efforts on National Park Service (NPS) lands in Point Reyes National Seashore (PORE) and Golden Gate National Recreation Area (GOGA), and in adjacent Mount Tamalpais State Park lands (Flannery et al. 2001). These points were re-surveyed in 2018 as part of the One Tam landbird monitoring effort. Site selection for these historic points included modified stratified random sampling for some of the points or for the starting point of a transect, whereas others were selected with less randomization in order to place transects across dominant vegetation habitats in the parks. Two of the historic mixed habitat transects (Morse’s Gulch and Stinson Gulch) were established in 1997 based on randomly generated points for small mammal surveys conducted by the US Geological Survey; at each of the two sites, one small mammal survey point served as a songbird survey point that became the starting point for the entire point count route, which was surveyed by Point Blue (Gardali and Geupel 1997).

Historic points on land managed by Marin County Parks (MCP) and private property adjacent to French Ranch Open Space Preserve (Table 3) were originally surveyed in 2009 and were repeated in 2019 under a separate agreement with Marin County Parks (that also included surveys on MCP lands outside the One Tam region). The purpose was primarily to help fill the gap in grassland songbird data (Gardali et al. 2016) due to their location within the One Tam boundary and the existence of multiple grassland points within the historic transect. All points on that historic transect were resurveyed this year regardless of habitat, also consistent with the One Tam historic mixed-habitat monitoring component of this study. These points were originally established as part of a multi-preserve survey effort for the purpose of developing spatial models of bird species distribution and diversity within areas managed by MCP and MMWD to assist those agencies with resource planning and management using landbirds as indicators (Gardali et al. 2010b). Site selection for the larger project varied across transects between using random

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starting points for the transect and areas where there was site-specific avifauna survey interest (specifics for this transect are unknown). For the new points, some prioritization of preserves with grasslands within the One Tam region occurred, in consultation with MCP staff. More on this landbird monitoring effort will be in a separate report to Marin County Parks (DiGaudio et al. in prep); some of that is duplicated herein because of its relevance to the overall One Tam effort.

Continuous Long-Term Sites (Mixed Habitats): Continuously monitored riparian point count stations at Redwood Creek were first established by Kern River Research Center (KRRC) in 1995 as part of a riparian Brown-headed Cowbird study initiated by KRRC and GOGA in GOGA and PORE (Gardali and Geupel 1997). Point Blue took over the point count stations in 1997 and have surveyed these points annually since.

For the continuously monitored MMWD point counts, which were established in 1996 by Point Blue, the starting points for each transects were chosen at random and distributed evenly throughout the study area. From each starting point, the nearest unpaved road or trail was used for the transect, and direction of travel was also random when possible (Geupel et al. 1997).

New Sites (Grassland): New grassland point count stations were selected, established, and surveyed in 2018 (NPS and CSP lands) and 2019 (MMWD and MCP lands) within the One Tam region (Table 2, Figure 1). On lands managed by NPS and CSP, we established entirely new transects. In MMWD, we established a combination of entirely new transects and additional points on pre-existing transects (Table 2). In MCP, we added additional points on a pre-existing transect, extending to the contiguous Roy’s Redwoods Open Space Preserve (but under the initial transect name, “French Ranch”, named for the open space preserve where points were originally placed; Tables 2 and 3).

Considerations that went into selecting the locations for new grassland points included habitat type determination, grassland patch size, and access logistics.

Habitat Type and Patch Requirements. Habitat included both annual and perennial grasslands, based on GIS vegetation layers provided by GGNPC. We established points based on the presence of a contiguous grassland patch (e.g., could fit 2 or more points based on buffer and distance requirements- see below), or in some cases placed them in an isolated patch if it was near where we were establishing additional points in a contiguous patch or if adding onto a pre-existing continuous transect. For new transects, grassland points were established if they could be combined into a transect or two or more subtransects (i.e., allowing at least 5 points to be surveyed on the same morning). For existing transects, new grassland points were added if it was reasonable to add to the initial transect and still complete all points within the transect in one morning, or split the now-longer transect in two and conduct across two mornings, allowing at least 5 points to be surveyed on the same morning. This approach was done for efficiency and was also supported by the evidence that grassland birds do not typically occur in small, isolated patches (Vickery 1996, Ribic et al. 2009, DiGaudio 2012.

Habitat Buffers. Points were established at locations that had ≥50 m buffer from non-grassland habitat (on all sides), and we aimed for ≥100 m where that was possible without reducing the number of points

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in a patch or transect. Our buffer criteria did not necessarily require 100% grassland within the 50 m buffer (as an occasional tree or even clump of trees does not convert the habitat from grassland), but sites with a predominant habitat type other than grassland within 50 m were excluded. The two buffer exceptions were for scrub in a coastal prairie setting within a patch designated otherwise as predominantly grassland; and the existence of a waterline edge, when a grassland had a reservoir within <50 m of one side, but did not have a different terrestrial habitat within 50 m.

Access Logistics. A few access logistics were considered. Points were placed on trails if it fit buffer requirements and did not diminish the number of points we could fit into a transect, in order to (1) increase efficiency of conducting the survey in a given morning, and (2) reduce impacts to the vegetation. If this was not possible (which was often the case), off-trail points were added. The inclusion of off-trail points required that the points were at a reasonably accessible location in accessible terrain, and allowed the biologist to complete the transect in a reasonable amount of time. Topography was considered so that points on excessively steep slopes were adjusted or rejected if it would be extremely challenging to access or would reduce the number of points that could be surveyed in a given morning.

Selection Process. Point locations were selected using a combination of ArcGIS and the vegetation and trail layers therein, provided by GGNPC, and Google Earth, where habitat, buffers (distance from other habitat as well as from other points), and access were all evaluated. They were subsequently ground- truthed in the field, with the same habitat, buffer, and access considerations evaluated before confirming the establishment of the point, upon which some points were dropped or their exact location adjusted.

New point locations were placed at least 250 m apart; longer distances between points occurred if at 250 m from the prior point, the grassland failed to meet grassland point selection criteria as described above. In those cases, the location was typically selected beyond the 250 m location in increments of 25 m until an appropriate location was identified, or a random distance beyond 250 m if placement only at 25 m increments would result in fewer points than could otherwise be established.

Departure from Initial Assessment. The number of new grassland points established was not equal to the number we projected in the original scope of work. In the scope, only coarse estimates were made of the number of points that could be added, whereas once the project began, the above considerations often reduced the number of locations where it was appropriate to add a point. This resulted in adding fewer points to a given area, or in some cases, not adding any points to an area that had been predesignated in the project scope of work (e.g., the Dipsea Grasslands, because of distance to other point count stations; Azalea Hills / Bo-Fax area (near Alpine Lake), because of steepness and remoteness of points; and Laurel Dell, where buffer requirements were not met).

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Statistical Analysis

We analyzed point count data to provide information on the presence and relative abundance of grassland species, total abundance (of all species and habitats), species richness (number of species), and species composition. Relative abundance is defined as the mean number of detections per visit per point, and species richness is the mean number of species per point, cumulative across visits (all points were visited 2 times). Averaging the indices in this way controls for the different number of point count stations surveyed within each group. We calculated and compared these indices across three groups of One Tam points: new grassland points (n = 88 points), historic revisited points in mixed habitats points (n = 102 points) historic points), and continuously monitored long-term points (n = 361 points

For both the grassland and mixed habitat points, we standardized detection rates by only including detections within 100 m of the observer for analyses, thus assuming that detection probabilities in grassland habitat were similar within this distance. For the grassland points, excluding detections that were beyond 100 m also removed many of the non-grassland bird species associated with the adjacent coastal scrub and forest habitats. Note that typical analysis of point count data from non-grassland habitat (i.e. the historic revisited and continuously monitored points in mixed habitat) would only include detections within 50 m of the point rather than 100 m, as had been done historically for analysis of other long-term monitoring points within One Tam (e.g., Cormier et al. 2017). A 100 m cutoff for detections is more appropriate in grassland habitat, since bird densities are typically much lower in grasslands compared to forest or shrub dominated habitats. Also, because of the openness of grassland habitat, detection rates between 50 m to 100 m is higher than compared to forested habitats. For our analysis we chose to use the 100 m cutoff across all habitat types so that we can compare grassland results across all sites.

To define which bird species should be considered a ‘grassland bird’ for this project, we referred to the list of grassland focal species described by California Partners in Flight (CalPIF in review). The underlying concept of the focal species approach is simply that by managing habitat to maintain the conditions that support populations of focal species, the appropriate conditions will be maintained to support diverse and healthy ecosystems (Chase and Geupel 2005). From the CalPIF list of 23 focal species (CalPIF in review), we selected a subset of 15 species that could potentially breed within the One Tam region (Table 4). These species were selected based on a combination of expert opinion and published accounts of breeding for each species within Marin County (Shuford 1993). The CalPIF grassland focal species can be divided into two broad categories: (1) grassland ‘specialists’, which nest on the ground in grasslands and require extensive grassland habitat; and (2) grassland ecotone / savannah, or ‘edge’ species, which include some species that nest in trees, shrubs, or cavities, but depend on grasslands and open country for foraging or other aspects of their life history (Table 4). In addition to the CalPIF grassland focal species, we also included two additional edge species: Chipping Sparrow, and Lazuli Bunting (Table 4); we selected these species because they are often associated with grassland or grassland edge habitat within the One Tam region, including in this study (pers. obs.).

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Table 4. Grassland focal species that may potentially nest within the One Tam region. Focal species are based on California Partners in Flight grassland focal species (CalPIF in review) plus two additional post hoc species (based on our own observations from this study). Species listed include those that were detected at least once by Point Blue during the 2018-19 One Tam landbird surveys, as well as species that could potentially occur based on the geographic range of the species, and expert opinion.

Focal Species Scientific Name Conservation Status1 CalPIF focal species that are grassland specialists (nests exclusively in grasslands) Burrowing Owl2 Athene cunicularia CA BSSC, FWS BCC Grasshopper Sparrow Ammodramus savannarum CA BSSC Horned Lark Eremophila alpestris Lark Sparrow Chondestes grammacus Savannah Sparrow3 Passerculus sandwichensis alaudinus CA BSSC Western Meadowlark Sturnella neglecta CalPIF focal species that are grassland ecotone or edge species American Kestrel Falco sparverius Barn Owl Tyto alba Golden Eagle2 Aquila chrysaetos FWS BCC, CA FP Killdeer Charadrius vociferus Loggerhead Shrike2 Lanius ludovicianus CA BSSC, FWS BCC Northern Harrier Circus cyaneus CA BSSC Western Bluebird Sialia mexicana Western Kingbird Tyrannus verticalis White-tailed Kite Elanus leucurus CA FP Post Hoc grassland ecotone or edge focal species Chipping Sparrow Spizella passerina Lazuli Bunting Passerina amoena 1CA BSSC = California Department of Fish and Wildlife (CDFW) bird species of special concern (Shuford and Gardali 2008); FWS BCC = U.S. Fish and Wildlife Bird of Conservation Concern (U.S. Fish and Wildlife Service 2018); CA FP = CDFW fully protected species (https://www.dfg.ca.gov/wildlife/nongame/t_e_spp/fully_pro.html) 2Species is possible but not likely to breed here based on current regional distribution. 3The local subspecies, “Bryant’s Savannah Sparrow”, which breeds in coastal California and occurs within the One Tam region is a California bird species of special concern at the subspecies level.

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Assessing Coverage and Habitat for One Tam Landbird Monitoring

To assess our current landbird monitoring coverage of the different habitat types within the One Tam region, we (1) assessed the relative proportion of each habitat type within the One Tam region, and (2) characterized the dominant habitat type within a 100 m radius of each point count location within One Tam. For this assessment we included all 551 points within the One Tam region – the 88 new grassland points surveyed in 2018-19, 102 historic revisited points surveyed in 2018-19, and the 361 continuously monitored points (Table 1, Figure 1). To determine habitat types around points, and for One Tam as a whole, we relied on the CalFIRE FRAP vegetation raster (CAL-FIRE 2015), which classifies vegetation for the entire state at a 30 m pixel resolution according to the California Wildlife Habitat Relationship (WHR) system. We used this layer instead of the vegetation GIS sources GGNPC provided because it provided a more complete coverage, without gaps, of the One Tam region. Furthermore, working with the CalFIRE FRAP vegetation layer, a composite raster database, was more logistically feasible for analyzing spatial data than compared to the vegetation files GGNPS provided, which were in three separate vector (polygon) databases.

To determine the amount of habitat represented within One Tam, we tabulated the area of each WHR class represented within the One Tam region boundary, and then calculated the percent of total area of the region for each WHR class. To characterize the dominant habitat type around point count stations, we calculated the total area of each WHR class within a 100 m radius buffer polygon around each point, and then determined which WHR comprised the dominant vegetation class for each point. From this we tabulated the number of points that accounted for each WHR class. For calculating habitat type areas we used the “tabulate area” spatial analyst tool in ESRI ArcMAP. We used 100 m radius buffers around each point because this was the distance at which we analyzed bird metrics. In order to have the resulting WHR classes better reflect habitat categories relevant to bird communities, and have these habitats be comparable to how bird communities were grouped in the Peak Health report (Gardali et al. 2016), we aggregated related WHR classes into broader habitat types, with a few exceptions: we kept separate coastal scrub and chaparral from one another, and kept redwood forest separate from other coniferous forest types, because of the differences in their range, management or conservation, and some components of their bird community. For example, WHR classes “Closed-Cone Pine-Cypress”, “Douglas Fir”, and “Montane Hardwood-Conifer” were lumped together to represent “Other Conifer”. The WHR-habitat groupings are all shown in Appendix B.

RESULTS Bird Species Composition

A total of 107 bird species were recorded within the One Tam region from point count surveys in 2018 and 2019; this total includes all distance and fly-over detections (see Appendix A for complete species list); A total of 88 species were detected from the 88 new grassland points, 79 species were detected from the 102 historic revisited points in mixed-habitats, and 90 species were detected from the 331 continuously monitored points (Table 5). Seven grassland focal species were detected from the new grassland points, whereas only three grassland focal species were detected from the historic revisited

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points and four grassland focal species were detected from the continuously monitored points (Table 5, Appendix A). The grassland focal species found at the new grassland points were White-tailed Kite, American Kestrel, Horned Lark, Grasshopper Sparrow, Lark Sparrow, Savannah Sparrow, and Western Bluebird. Grasshopper Sparrow and the subspecies of Savannah Sparrow that occurs here (Bryant’s Savannah Sparrow) are both California Bird Species of Special Concern (Table 4; Shuford and Gardali 2008). Chipping Sparrow, Western Bluebird, and White-tailed Kite were also detected from the historic revisited and continuously monitored points. Killdeer, another grassland focal species, was detected from the continuously monitored points; however this record is from just one individual detected from >100 m from one point. New Grassland Sites vs. Historic Revisited and Continuously Monitored Sites

Average total abundance and total species richness was roughly twice as high at both the historic revisited and continuously monitored points compared to the new grassland points (Table 5). However, richness and abundance of grassland species (both specialists and edge species) were higher at the new grassland points (Table 5). In fact there were no grassland specialists detected at the historic revisited or continuously monitored points in 2018-19 (including >100 m detections), and two out of five edge species detected in the new grassland points were not detected at any of the historic mixed habitat points. Two of the grassland focal species – Horned Lark (a grassland specialist) and White-tailed Kite (an edge species that is not surveyed well with the point count method) – were only detected greater than 100 m from points. A Horned Lark was only detected on one occasion, singing > 100 m from a point on Blue Ridge Fire Road on MMWD land, and appeared to be singing from over the MMWD boundary line on adjacent private property. White-tailed Kites were observed foraging over grasslands from four points, on Bathtub Trail, Worn Springs Road, French Ranch, and Bull frog/Bon Tempe Road.

Site-specific relative abundance of grassland species is shown in Table 6 (translations for 4-letter site codes can be found in Table 2). The NPS grassland transects are the only sites that had any of the grassland specialists (Grasshopper Sparrow, Lark Sparrow, and Savannah Sparrow) within 100 m (Table 6). No grassland specialists were detected at the new MMWD grassland sites, with the exception of one Horned Lark that was heard signing > 100 m away on adjacent private property, as noted above. The geographic occurrence of the grassland specialists appear to be limited to grasslands in the northwestern area of the One Tam region (Figure 2). Outside of these northwestern grassland sites, we had just one detection of a specialist species, a Grasshopper Sparrow, which was from Coastal Trail / South of Ridgecrest (CTRI). The NPS grasslands also had the majority of Western Bluebirds (and other edge species), where they occurred at four out of the six NPS transects (Table 6). Furthermore, Northwest Corner of One Tam (NWCO), an NPS site, was the only site that had American Kestrel. Of the six NPS grassland sites, only one, Rancho Baulines (RABA) – which includes grasslands around the Rancho Baulines at the south end of Bolinas Lagoon and grassland patches in Dogtown – did not have any grassland species (Table 6).

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Table 5. Average relative abundance (with standard error parenthetically) for grassland focal species among the new grassland point count stations surveyed by Point Blue in 2018-19 in the One Tam region (n = 88 points) compared to historic mixed habitat points (n = 102); and continuously monitored points that were surveyed in 2019 (n = 361). Average relative abundance = number of individuals detected within 100 m of point averaged across visits and points; those detected but only as flyovers or > 100 m from the point are indicated with “**”. Community indices total abundance and species richness includes all species (not just grassland species). New Grassland Points Historic Mixed Habitats Continuously Common Name 2018-19 2018-19 Monitored

Grassland specialists Grasshopper Sparrow (GRSP) 0.05 (0.02) none none Savannah Sparrow (SAVS) 0.01 (0.01) none none Lark Sparrow (LASP) 0.03 (0.02) none none Horned Lark (HOLA) ** none none Grassland and savanna or edge species American Kestrel (AMKE) 0.01 (0.01) none none Chipping Sparrow (CHSP) 0.03 (0.01) 0.01 (0.01) 0.01 (0.01) Killdeer (KILL) none none ** Lazuli Bunting (LAZB) 0.01 (0.01) none 0.004 (0.002) Western Bluebird (WEBL) 0.10 (0.04) 0.03 (0.01) 0.02 (0.01) White-tailed Kite (WTKI) ** ** ** Community Indices Total Abundance 4.87 (0.47) 9.89 (0.33) 11.00 (0.22) Species Richness 5.24 (0.32) 9.98 (0.34) 10.73 (0.21) Total Species Richness 88 79 90

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Table 6. Mean abundance per point per visit of grassland and grassland edge landbird species by site at new grassland point count stations surveyed by Point Blue in 2018-19 in the One Tam region (observations within 100 m of points). Number of points for each transect in grassland habitat are shown next to transect code; standard error of the mean given in parenthesis next to each value; blank indicates either no detections for that site, or observations were > 100 m from points.

Transect Grassland Specialists Grassland Edge Species (w/ # of Grasshopper Lark Savannah American Chipping Lazuli Western grassland Sparrow Sparrow Sparrow Kestrel Sparrow Bunting Bluebird pts) BATH (3) BLUE (4)

HICO (1) LAVR (1) OHFR (1) MMWD PIMR (3) RICR (6) 0.08 (0.08) WSRO (6) 0.08 (0.08) BORE (7) 0.07 (0.07) 0.29 (0.18) CTRI (13) 0.04 (0.04) 0.31 (0.19) NWCO (9) 0.11 (0.07) 0.06 (0.06) 0.06 (0.06) 0.06 (0.06) 0.17 (0.08)

NPS RABA (9) RAGE (10) 0.1 (0.07) WESG (9) 0.11 (0.11) 0.22 (0.12) 0.06 (0.06) 0.28 (0.09) 0.11 (0.11)

CTRI (13) 0.04 (0.04) 0.31 (0.19)

CSP

FRRA (6) 0.06 (0.06) 0.06 (0.06)

MCP

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Figure 2. Locations (large yellow circles) where grassland specialists (Grasshopper Sparrow, Lark Sparrow, Savannah Sparrow) were found within 100 m of points surveyed by Point Blue in 2018-19 in the One Tam region. Smaller yellow circles are grassland points where no grassland specialists were detected.

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Habitat Coverage Assessment

According to our habitat assessment using the CAL-FIRE FRAP vegetation layer, there are 29 different Wildlife Habitat Relationship classes (2015), within the One Tam region (Appendices B; CAL-FIRE 2015). If aggregating related WHR classes into the broader habitat types described Methods, the dominant One Tam habitat is coniferous forest (34% of the One Tam region), with redwood accounting for 15% alone (Figure 3A). Oak woodland comprises 26%, grassland 10%, coastal scrub 9%, chaparral 8%, urban 7%, and the remaining 6% was categorized as “other” (Figure 3A and Appendix B). Riparian habitat comprises a mere 0.3% of the One Tam region (Appendix B).

Of the 551 point count locations within the One Tam region (including the new grassland, historic revisited, and continuously monitored points), coniferous forest is the dominant habitat around 37% of the points, with 17% and 19% of the points being redwood and Douglas fir dominated, respectively (Figure 3B, Appendix B). Grassland habitat accounts for 23% of all the points, oak woodland 16%, chaparral 14%, riparian habitat 4%, and coastal scrub 3% of the points (Figure 3, Appendix B). The remaining 4% was categorized as “other”, and includes eucalyptus forest, montane hardwood other than oak, wetland, urban, and barren. The majority (69%) of the points that have grassland as their dominant habitat are comprised of the 88 new grassland points established in 2018 and 2019, and all of the coastal scrub points are historic revisited points (Appendices B and C). See Appendix C for a breakdown on the number of points per dominant habitat by land manager.

Riparian Other Oak Urban Other Urban 4% Oak 7% Woodland <1% 2% 7% Woodland 26% 16% Grassland Grassland 10% 23%

Chaparral 8% Redwood Redwood 17% 15% Chaparral 14% Coastal Scrub Other Other Conifer 9% Coastal Scrub Conifer 18% 4% 20% (A) Habitat in One Tam (B) Habitat at Points

Figure 3. Habitat coverage breakdown for (A) the entire One Tam area of focus and (B) relative percentage of all point count stations (n = 551) surveyed by Point Blue in 2018-19 in the One Tam region, according the dominant habitat type within a 100 m radius. *Percent riparian within One Tam region (0.3%) not shown in Fig. 3A.

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DISCUSSION

The goal of this study was to fill information gaps in our current assessment of landbird populations within the One Tam region, which would complement the existing long-term dataset for the region. However this existing long-term dataset has been largely limited to the assessment of bird populations from just one land manager in the One Tam region – MMWD – and produced limited information on the condition or trends of the region’s grassland bird community (Gardali et al. 2016). To fill these information gaps, we surveyed 88 new grassland survey points and revisited 102 historic survey points in mixed habitats in 2018 and 2019, on top of the 361 continuously-monitored points that were also surveyed during this two-year period outside of this effort as part of existing long-term monitoring programs. With data from the new grassland sites, the historic revisited sites, and the continuously monitored sites, we now have a much more detailed picture of the landbird communities within the One Tam region.

Grasslands

Despite the fact that grassland habitat only makes up approximately 10% of its area, we found that the One Tam region supports at least seven grassland bird species, including three grassland specialists and four grassland edge species (Table 5). Two of the grassland specialists are California Bird Species of Special Concern – the Grasshopper Sparrow and Bryant’s Savannah Sparrow (Shuford and Gardali 2008). If it were not for the addition of new grassland points, these and other grassland bird species would have been overlooked or undercounted within the One Tam region during this two-year period (Table 5). Three grassland specialists (Grasshopper Sparrow, Savannah Sparrow, and Lark Sparrow), and one grassland edge species (American Kestrel) were found at new grassland points, but were not encountered at the historic revisited or continuously monitored points (Table 5). The new grassland points were therefore successful in that they captured data on grassland species that were not otherwise being captured by existing points within the One Tam region.

The occurrence of grassland species was patchily distributed among the grassland sites we surveyed within the One Tam region. In general, the NPS grassland sites on the east side of Olema Valley supported most of the grassland bird species (Table 6). This was particularly true of the grassland specialist species – Grasshopper Sparrow, Brant’s Savannah Sparrow, and Lark Sparrow – although there was one Grasshopper Sparrow detection from CSP land along the Coastal Trail south of Ridgecrest Blvd (Figure 2). There were no grassland specialists and very few grassland edge species found at the MMWD grassland sites or the MCP site, French Ranch (Table 6), with the exception of a single Horned Lark detected singing > 100 m from a point on the Blue Ridge Fire Road transect. This individual Horned Lark was singing from adjacent private land ~ 500 m from the transect on a gravelly and barren rock outcrop – a habitat feature within grassland habitat that is distinctly attractive to Horned Larks. However this rocky habitat feature did not appear evident anywhere on the MMWD side of the fence here, and therefore we probably would not expect Horned Larks to use the MMWD portion of this grassland.

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We suspect the reason why certain sites had grassland birds and others did not is that their occurrence may be a function of grassland patch size and management. Other than identifying a habitat patch as “grassland”, and prioritizing larger patches over smaller patches for selecting new survey point locations, quantifying and characterizing specific habitat attributes was generally beyond the scope of this study. However, it was apparent to us that most of the MMWD and MCP grasslands we surveyed were relatively small in comparison to the NPS and CSP grasslands where we found grassland birds. Numerous studies have demonstrated that most grassland birds are area and edge sensitive, and generally prefer larger grasslands to smaller ones (Johnson and Igl 2001, Davis 2004, Ribic et al. 2009, DiGaudio 2012). Grassland habitat within the One Tam region is comprised of many relatively small and disjunct patches within a landscape dominated by forest, scrub, and chaparral. The smaller grassland patches, which are mostly found on MMWD lands, may simply be too small for what grassland bird prefer.

Related to patch size is habitat connectivity, and the NPS grassland sites in the northwestern corner of the One Tam region are essentially the southern terminus of an archipelago of grasslands that increase in size as you move north along the Olema Valley / Bolinas Ridge slope. Where Sir Francis Drake crosses Bolinas Ridge to the east of Olema there is an extensive grassland area, much larger than any patch in the One Tam region. During the breeding season this large grassland supports all three of the grassland specialists observed within One Tam, plus a fourth, Western Meadowlark (RTD, pers. obs). Perhaps the proximity of this larger grassland system is a contributing factor for why we found grassland birds especially at the NPS grassland sites in the northwest corner of the One Tam region.

The condition and management of the grassland may also be a factor explaining grassland bird occurrence. Of the 15 grassland transects we surveyed, livestock grazing was apparent at only four of them, all on NPS lands. Most of the grassland birds were found at these same four grazed NPS sites (Table 6). In fact, Savannah Sparrow and Lark Sparrow, two grassland specialists, were only found at the grazed sites (although note that Lark Sparrow has been detected in prior years on ungrazed MMWD land). And all but one of the Grasshopper Sparrow detections were from the grazed sites, the exception being a detection from a single point on Coastal Trail / south of Ridgecrest Blvd (Figure 2). Rancho Baulines, the only NPS grassland transect that did not have livestock grazing present, did not have any grassland birds. There were dramatic differences in the apparent habitat conditions between the grazed and un-grazed sites, particularly when comparing Rancho Baulines to the grazed sites (see Figure 4).

Though we did not collect vegetation data as part of these surveys, we observed in the field that the grazed grasslands generally had ankle to knee high vegetation, and supported a relatively diverse plant community including a good number of native perennial grasses. The Rancho Baulines site, which had not been grazed for at least the past several years (detailed history uncertain to authors) has a decadent grassland with a thick thatch layer, and abundant invasive weeds such as Italian thistle, poison hemlock, and exotic annual grasses. Additionally, coyote bush appears to be invading the grassland, and may indicate that this site is transitioning to coastal scrub habitat. The other non-grazed grassland sites on MMWD and MCP lands are similarly decadent (dense) with a lot of thatch buildup, but did not appear to

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be impacted by invasive plants as badly as Rancho Baulines; in fact, the grasslands along Bathtub trail on MMWD land supported exceptional examples of extensive native perennial grass stands.

Figure 4. Grassland photographs taken in 2018 (by Ryan DiGaudio), demonstrating the difference in vegetation characteristics. Left: “West of Shafter Grade” grassland site, which was grazed by livestock and supported grassland specialist species Grasshopper Sparrow, Lark Sparrow, and Savannah Sparrow. Right: “Rancho Baulines” grassland site, which was not grazed (but was historically) and where we did not find any grassland birds in 2018.

The relationship of various management regimes (including grazing, burning, and mowing) on grassland bird communities is complex, and can yield contradictory results depending on various factors, such as the particular bird species, type of grassland, climate, and various parameters around particular management practices (Saab et al. 1995, Krausman et al. 2009). For example, Grasshopper Sparrows appear to benefit from light to moderate grazing regimes in productive grassland habitats of the tallgrass prairie and eastern hayfields, whereas grazing is considered detrimental to Grasshopper Sparrows in arid grasslands, such as the interior California grasslands and desert southwest (Saab et al. 1995, Fitton 2008, and Unitt 2008). Our research on coastal grasslands in Sonoma County suggest that livestock grazing may be compatible and perhaps beneficial to certain grassland birds in mesic coastal prairies (DiGaudio 2010). In addition to the relationship between grazing and grassland birds, other studies have shown that grazing may also be a useful management tool for promoting native plant diversity in California coastal prairies, the most species rich grassland type in North America (Stromberg et al. 2002, Hayes and Holl 2003). However, determining the appropriate amount of grazing in terms of intensity and timing is challenging because these factors vary year to year and region to region depending on climate, soil type, topography, and plant community (Krausman et al. 2009). We acknowledge that drivers other than grazing history may be behind these observed differences among the sites, and also that site-specific management and conservation issues may be influencing the management at each unit or site, and we are therefore not specifically suggesting grassland management recommendations here.

One of the challenges in monitoring grassland bird populations is that certain species can be irruptive from one year to the next. Grasshopper Sparrows are particularly mercurial in that they can be abundant at a site one year and absent the next, regardless of habitat condition (Vickery 1996; Point Blue unpubl. data). In fact, it has been noted that Grasshopper Sparrow abundance is not necessarily an

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indication of habitat quality (Vickery 1996). An interesting phenomenon observed in coastal California is that Grasshopper Sparrow abundance sometimes changes late in the breeding season, when influxes of birds can arrive as late as June (Shuford 1993). The reason for this late season pulse is unknown, though it has been suggested that Grasshopper Sparrows may breed earlier in the year in grasslands to the south or inland when conditions are ideal at these sites, and then after the grasslands dry up, along with food resources, the birds move to the still green coastal grasslands for a second round of breeding (Shuford 1993). The monitoring implication of this is that on some years Grasshopper Sparrows could be undercounted during the first round of surveys in May and possibly even on the second round of surveys in June, depending on the timing; and that fluctuating numbers of Grasshoppers Sparrows over time is not necessarily reflective of their population nor the habitat quality of One Tam’s grasslands.

An ancillary finding we discovered from the grassland point count surveys was that there were a number of non-grassland bird species that were apparently more abundant at the grassland points, which often also sampled edge habitat, compared to the mixed-habitat historic revisited and continuously monitored points. We suspect that is because these species are all associated with edge habitat, and may prefer ecotones, particularly forest edge or open woodland habitat. Examples include Red-tailed Hawk, Ash-throated Flycatcher, and Audubon’s Warbler (the local breeding race of Yellow-rumped Warbler). The Audubon’s Warbler, a species typically associated with coniferous forests as its breeding habitat in Marin, was especially abundant along two grassland transects, Ridgecrest and Coastal Trail / South of Ridgecrest. This may reflect the habitat matrix in that area, or also may reflect other features that influence Audubon’s Warbler occurrence or abundance in that area overall. Despite the fact that our grassland points captured data on these and other edge species, given our study design for how the new grassland points were established, the new grassland points may not be appropriate for assessing edge species trends. This is because we established points with at least a 50 m radius buffer that excludes non-grassland habitat, which would exclude most edge-habitat; and analysis on non-grassland species, such as Audubon’s Warbler, is typically done at a 50 m radius around points. However, points from the continuous MMWD study that sample, but do not target, grasslands may be appropriate for analyzing edge species in the future, and we way want to consider ways in which we could use these data to better understand the distribution and possibly trends of edge species.

Historic Revisited Points in Mixed Habitats

We have a long history of monitoring within the One Tam region. However most of the existing long- term time series monitoring data is almost entirely from MMWD lands, and does not sufficiently cover the other major land management agencies within One Tam. As stated in the Peak Health report (Gardali et al. 2016), we can only truly assess the condition and trends of bird populations on a mountain-wide scale if we included all of the major management agency jurisdictions in our bird monitoring efforts. In practice this means expanding bird survey effort coverage to include NPS, CSP, and MCP lands, in addition to the MMWD lands already covered. Fortunately, we already had historic point count transects established on these multi-jurisdictional lands, which had not been surveyed for approximately two decades. This One Tam study afforded us a unique opportunity to “resurrect” many of these old survey transects, which totaled 102 historic points across 10 transects in mixed habitat

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types, and were spread out on lands managed by NPS, CSP, and MCP, and to limited extend included some private lands (including Audubon Canyon Ranch land).

Revisiting these transects, however, was not without its challenges, and some transects (e.g. Morse’s Gulch and Stinson Gulch) were difficult to access due to changes in trail condition and two decades worth of habitat succession. Given these challenges, plus constraints of our funding and personnel time (as the more difficult to access transects required more time to cover), a small number of points could not be resurveyed. Ultimately, however, these transects proved mostly accessible and potentially could be surveyed again – including potentially the non-repeated points – should monitoring at these sites continue and capacity allow the reduced number of points that can be surveyed in a given morning.

As we consider what a future bird monitoring program should look like for One Tam (discussed in more detail in the Monitoring Recommendations section below), including some or all of these historic points would improve our ability to achieve the Peak Health report’s goal of assessing the condition and trends of bird populations on a mountain-wide scale. Such monitoring depends on the priorities of the local land management agencies, including not only jurisdiction, but also geography, avian species community, and habitat.

Habitat Coverage Assessment

The historic revisited point count effort covered an array of multiple habitat types, and mirrored roughly the same breakdown of habitat types covered by the continuously monitored point count effort on MMWD lands (Appendix C). With the addition of the new grassland points, we now have survey coverage of all of the major habitat types. In fact, we have surveyed the vast majority of grasslands within the One Tam region (Figure 1 map). Additionally, the historic revisited points included 19 points (4% of all points) that are dominated by coastal scrub habitat (within a 100 m radius). Coastal scrub habitat was not represented among the continuously monitored points, so the inclusion of these historic points greatly improves our coverage of coastal scrub, which comprises 9% of the One Tam area, Maintaining or increasing the amount of coastal scrub coverage in future bird monitoring should remain a goal. Having adequate coverage of coastal scrub and its associated bird community is important because this habitat type may be become impacted through natural successional processes, as has been documented extensively at the nearby Point Blue Palomarin field station in Point Reyes National Seashore (Porzig et al. 2014, 2018). That said, with the inclusion of these historic points, the coverage may be focused on late-successional coastal scrub, and not necessarily reflect the overall coastal scrub community in the region.

Although our approach for quantifying and characterizing habitat coverage around point count locations was useful in that it provided a good, if not coarse broad-brush assessment of habitat coverage, there are a few caveats to consider. For one, we did not assess the accuracy of the CalFIRE FRAP vegetation layer used for this assessment. Also, this raster database is at a 30 m by 30 m pixel resolution, which is acceptable for a coarse landscape assessment, but perhaps not ideal for fine scale assessments. Furthermore, we assessed habitat from within a 100 m radius of each point, the same distance used for analyzing grassland point count detection data. The distance cutoff in typical analyses for mixed-habitats

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(non-grassland) is 50 m, however the habitat assessment was done out to 100 m at these points as well for consistency. Perhaps future habitat assessments for the non-grassland points should be restricted to 50 m around the points rather than 100 m.

Another limitation of our method for assessing dominant habitats is that it did not take into account the sub-dominant habitats around points, and these sub-dominant habitats could also influence bird community characteristics at a given point. For example, a point with “Redwood” identified as its dominant habitat could have 40% redwood, 30% coastal scrub, and 30% grassland; such a hypothetical point may have more non-forest birds than forest birds associated with it.

Similarly, there were a number of points identified as “grassland” dominated that would not fit our criteria for selecting new grassland points. For example, a grassland-dominant point could have had 30% grassland, 25% chaparral, 25% coastal scrub, and 20% conifer (or some such mix), yet still be classified as “grassland”. Furthermore the historic points classified as grassland may not fit the buffer restrictions applied to new grassland points, and/or they may not be part of contiguous grassland patches, another criteria used for selecting new grassland points. Nevertheless, 100% of the new grassland sites were classified post hoc as grassland being the dominant habitat to 100 m. A quick assessment of the 40 historic revisited and continuously monitored points that were classified as grassland dominated revealed that only 12 of these points would fit our grassland selection criteria.

The following section outlines recommendations for future monitoring, based on our pre-existing continuously monitored programs and what we have learned and reported above for the historic revisited and new sites surveyed in the past two years.

MONITORING RECOMMENDATIONS

The expanded landbird monitoring efforts in One Tam in 2018 and 2019, combined with the existing continuous monitoring efforts, have given us a more detailed picture of the region’s bird communities on a mountain-wide scale. However this picture is but a snapshot in time, as we only have one year of data from each of the new grassland sites, and two years of data that are generally 20 years apart for the historic revisited sites. Repeated surveys of the new grassland sites over multiple years is necessary before we can examine grassland bird trends within the region; by also including in future monitoring efforts the historical revisited sites in mixed habitats, we will be able to assess the condition and trends of bird communities on a mountain-wide scale. The following section offers recommendations and considerations for future landbird monitoring within the One Tam region, outlined with an eye towards accomplishing the recommendations of the Peak Health Report chapter for birds (Gardali et al. 2016): to expand existing landbird monitoring within the One Tam region to additional jurisdictions to better assess the health of the avian community on a mountain-wide scale; and to give special attention to grassland habitat, as well as coastal scrub.

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Grassland Bird Monitoring Recommendations

 Based on our findings from the 2018-19 survey efforts in One Tam, we strongly recommend prioritizing the continued, long-term monitoring of all new NPS and CSP grassland point count transects in One Tam (57 points across 6 transects: Borello / Highway 1, Coastal Trail / South of Ridgecrest, Northwest Corner of One Tam, Rancho Baulines / Dogtown, Ragetti / Highway 1, and West of Shafter Grade Trail). Through continued monitoring at these sites, we expect to maximize our ability to assess status and trends for grassland bird species within the One Tam region. Continued monitoring at these sites is particularly important for assessing grassland specialist species, which we detected at five of these six transects (two of which are California Bird Species of Special Concern – Grasshopper Sparrow and Savannah Sparrow; Shuford and Gardali 2008), as these species are currently not assessed by the existing group of continuously monitored points within the One Tam region. At the sixth (Rancho Baulines / Dogtown; RABA), we believe it is worth continued monitoring based on the detections of grassland specialists in nearby grasslands in that area of One Tam, the overall patch size being appropriate for hosting grassland specialists, and the potential changes to habitat (with vegetation management or habitat succession) at this site.

 We similarly recommend continued, long-term monitoring at the 6 new grassland points on the pre-existing continuously-monitored Ridgecrest (RICR) transect in MMWD. As with the RABA transect, we did not detect grassland specialists there during the 2019 point count season; however, we think there is potential for grassland specialists here as this area is part of a larger grassland complex contiguous with the same grassland habitat surveyed by Coast Trail South of Ridgecrest (CTRI), where one Grasshopper Sparrow was detected in 2018.

 We recommend not continuing to monitor the newly established grassland points at French Ranch and Roy’s Redwoods open space preserves in MCP, where we had no grassland specialists and do not expect them there under current patch size and habitat characteristics, and where excessive road noise from Sir Francis Drake interferes with detectability.

 We similarly recommend not continuing to monitor the new grassland points in MMWD at the three new small and isolated grassland transects (Bathtub Trail, Blue Ridge Fire Road, and Worn Springs Road), or in the newly-established grassland points that were added to four additional continuously monitored MMWD transects (Hidden Cove, Lakeview Road, Oat Hill Road, and Pine Mountain Road), due to our expectation that these are unlikely to support grassland specialists.

 We recommend continuing to monitor the continuously monitored points where grassland was determined to be the dominant (or secondary) habitat type, and which were established and monitored prior to 2018 as part of mixed habitat monitoring efforts. These included a combination of continuously monitored and historic revisited points. Although no grassland specialists were detected in 2018-19 at these points, some have been detected historically. Monitoring these points is also valuable because many of these points sample grasslands of smaller patch sizes that do not always adhere to the buffer rules of the grassland points established in 2018-19; continuing to monitor grasslands of smaller patch sizes allows the birds

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associated with edges and smaller openings to be included in the larger monitoring regime, as areas with such characteristics are common throughout the One Tam region. For example, we found the conifer associated Audubon’s Warblers to be over three times more abundant in points designated as grasslands, presumably because of how they forage along the forest edge. Because of encroachment, those areas may also be of management interest to land managers.

Additional considerations for grassland bird monitoring:

 Consider conducting grassland bird monitoring at the above point count stations following the once every third year approach that is conducted at MMWD and across many of our study sites throughout the region (Gardali et al. 2010a, Humple and Gardali 2015, Humple et al. 2017).

 If funding capacity allows, consider conducting annual grassland surveys at grassland-dominated transects to capture interannual variability and increase our understanding of avian use of these grasslands by grassland specialists, especially for the irruptive Grasshopper Sparrow (Shuford 1993, Vickery 1996). This would increase our understanding of occurrence and distribution, although would not necessarily increase our power to detect long-term trends.

 Consider the value of conducting a power analysis to determine if it will be possible to pick up trends in grassland bird species. Grassland bird densities are much lower compared to other terrestrial habitats, especially in regions such as One Tam where they are patchily distributed (even within the grasslands), and thus to achieve large enough sample sizes to perform trend analysis requires substantially more points compared to what is needed for birds in many other terrestrial habitats (riparian, forest, scrub). Nonetheless, we still may be able to detect major changes or evaluate patterns of presence/absence of grassland birds within the region, even if we are not able to detect trends with the same statistical rigor as may be possible for birds with larger sample sizes in other habitat types.

 Consider if there may be regional and land-manager interest in understanding and monitoring trends in grassland birds in the larger grassland complexes on public lands in Marin County that extend beyond the One Tam boundary. There are grasslands that are known to host grassland specialists, through historic point count surveys or anecdotal observations, and are connected to larger grassland patch ‘archipelagos’ and thus might have more grassland-specialist potential. These include portions of GGNRA north of One Tam along the Highway 1 corridor; in the Bolinas area as well as the Outer Point and Tomales Point of Point Reyes National Seashore; and possibly areas east of One Tam (including Mount Burdell Open Space Preserve, the location of a Point Blue / MCP study in 2018-19; DiGaudio et al. in prep). Some of these areas we know host grassland specialists. For the sites with historic data, we might be able to assess long-term trends sooner, if there is a sufficient sample size.

 Consider additional motivators for monitoring the study sites that were not specifically recommended by Point Blue in this report for future monitoring (e.g., the smaller grassland patches where points were established and surveyed in 2018-19 in MMWD and MCP). For example, if land managers have management actions planned for or conservation concerns

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regarding any of these grassland areas (e.g., new grazing regimes, Douglas fir abatement, scrub encroachment), we can repeat surveys, including potentially the inclusion of a before/after component prior to a proposed management activity. These also would not necessarily have to be monitored continuously if the management action might not occur for years, but can be repeated in timing with the action.

Mixed Habitat Bird Monitoring Recommendations

 We recommend continuing monitoring of all continuously monitored MMWD point count transects, which mostly are on MMWD lands, into the future. This will allow us to continue to build on an existing, extensive long-term dataset that dates back to 1996 and provides status and trends on dominant bird communities and how individual species are doing across a large portion of the One Tam area, and throughout much of the lands managed by MMWD. Acknowledging limited resources, we recommend continuing with the every-third-year approach for these sites.

 We recommend continuing monitoring of the Redwood Creek transect (which is actually a double transect) on NPS and CSP lands. This site is part of the I&M Riparian Landbird network for the San Francisco Bay Area network of parks (Gardali et al. 2010a, Humple et al. 2017), thus contributes to a broader regional understanding of how riparian landbirds are doing in national parks. This is also a core Palomarin Field Station study site, where constant effort mist-netting is generally conducted in spring through fall (funding permitting), allowing the collection of demographic data and contributing to the I&M effort looking at trends and demographics, as well as contributing to the keystone dataset out of Palomarin that focuses on a network of sites in west Marin County. Given the utility of using multiple monitoring methods in such intensive studies, and the annual mist netting conducted there, we recommend continuing this every year (instead of every third year) at Redwood Creek, as with all other core Palomarin Field Station study sites.

 We recommend continuing monitoring of most of the historic revisited point count transects that were resurveyed in 2018-19 but had not been surveyed in 10-20 years, in order to contribute to a better understanding of how the birds in the One Tam region are doing across habitats, jurisdictions, and geographies. In our assessment of how the birds are doing, extending monitoring to these sites allows us to make broader statements about the trends of birds in the region, without the caveat that the data are from predominantly one land manager, limited geography, or exclusive of certain dominant habitat types. This also allows us to take advantage of historic monitoring data that exist, rather than having to establish novel study sites, and to already be able to look at trends across decades. These study sites include (1) the French Ranch / Roy’s Redwoods (FRRA) historic points; as stated above, we do not recommend continuing to monitor the grassland points established at FRRA in 2019; and (2) transects at Ben Johnson Trail, Bootjack Trail, Eucalyptus Mill Valley, McCurdy Trail, Muir Woods Off-Trail, Randall Trail, and Stinson Gulch, on NPS, CSP, and private lands. By including the more coastal sites, this also allows us to significantly increase our monitoring of coastal scrub points, which was previously underrepresented in the continuous monitoring effort and identified as a data gap in the Peak

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Health Report (Gardali et al. 2016). The addition of historic points that are off-trail also expands the coverage within One Tam to not be entirely biased towards sites on trails.

 We recommend not continuing to monitor one of the historic revisited transects, Eucalyptus Mill Valley (EUMV), where eucalyptus forest is the dominant habitat. We do not see this as a conservation priority based on habitat as well as the fact that all the eucalyptus points are concentrated at this one study site, which would limit our ability to extend what we learn about birds in eucalyptus to eucalyptus forests in the One Tam region. Furthermore, according to our own habitat assessment, eucalyptus forest is a very minor habitat component of the One Tam region and accounts for 0.7% of its area.

Additional considerations for mixed habitat bird monitoring:

 Consider repeating surveys at the one transect located in eucalyptus forest in One Tam, Eucalyptus Mill Valley (EUMV), if there is interest by NPS in habitat management at this site. If that management is not imminent, but becomes of management interest in the future, we can use our data from 2000 and 2018, and repeat additional surveys at that time.

 Consider funding and personnel capacity as habitat succession advances. Assume that sites that are off-trail, or require off-trail access to get to, may take longer than they did in the future to survey. This includes Stinson Gulch (both the point resurveyed in 2018 and if want to repeat additional points here that we had to drop in 2018, due to the habitat succession no longer allowing survey coverage during the time period surveyors had capacity for), Morse’s Gulch, and potentially Muir Woods Off-Trail. Also consider personnel health and safety in the process (e.g., poison oak, the pressures of bushwacking through steep slopes), and impacts to the habitat, when assessing the appropriateness of revisiting points.

 Going forward, consider adding new coastal scrub points to improve survey coverage of this still underrepresented habitat within One Tam. Reasons to adequately capture bird trends within coastal scrub habitat include management concerns unique to coastal scrub habitat (e.g. Douglas-fir encroachment), and coastal scrub dependent species (e.g., Nuttall’s White-crowned Sparrow). If there are species or topics of conservation interest for coastal scrub that may not be best addressed within just the One Tam boundary, consider whether additional coastal scrub monitoring elsewhere would be beneficial (e.g., existing-continuous, new, or repeatable-historic sites throughout Point Reyes National Seashore, including at the Palomarin Field Station where habitat succession from scrub to Douglas-fir forest has been intensively studied for decades and continues to date; Porzig et al. 2014, 2018).

Recommendations & Considerations for the Overall Landbird Monitoring Program

 Consider the points that are sampling the avian community across more than one habitat type (e.g., RECR points that sample riparian and coastal scrub) in analysis and evaluation. This

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includes continuing to evaluate the birds in the region across all habitats by examining a suite of species that together represent all the relevant guilds and habitats in the One Tam region.

 If taking the every-third-year approach, consider whether these surveys could all be conducted in a single year, or could be split across 2-3 years in each 3-year period. Options could include repeating the points conducted in 2018 in 2021, and the points conducted in 2019 in 2022; sampling by habitat and/or land manager across the years; or stratified sampling and spreading across years. Funding sources should be considered in this approach (e.g., whether funding might be easier if spread across 2 or 3 years; or, conversely, whether a specific agency or institution might have funding only every few years), as well as field personnel capacity (e.g., splitting points across more than one year, given the robust number of transects, might be beneficial), and analytical impacts (e.g., how spreading this across years might impact how we examine trends).

 Consider where a non-jurisdictional approach is and is not appropriate: e.g., consider approaching reports, funding, contracts non-jurisdictionally, and what the trade-offs may be for this.

 Consider that a monitoring program that includes a combination of study sites under different monitoring schedules and establishment dates will require a new, intentional, and likely more complicated approach to trend analyses (e.g. mixed effects modeling).

 Consider exploring if we need to be assessing rare species of particular conservation concern in a different way. The point count method and overall approach recommended here is not necessarily appropriate for determining trends for some uncommon species, nor for certain taxa (e.g., raptors, owls). Our recommendations are just for this point count study, which aims to answer the general question of “How are the birds of the One Tam region doing?” More discussion would be needed if there is interest in expanding to species-specific efforts.

 Consider how monitoring efforts tie into land manager’s vegetation management plans.

 The overall study design of this effort is intended to combine avian species across all habitats, geographies, and jurisdictions and assess their health. Consider whether there might be questions of interest that would involve additional analyses based on habitats (e.g., redwoods, grasslands, coastal scrub) or other categories.

 Ensure future reporting is done in a way that feeds into the Peak Health report for birds and by habitat guilds (Gardali et al. 2016). Consider breaking down some of those habitat guilds (e.g., redwoods from other forested habitats; coastal scrub from chaparral) slightly further than done in the Peak Health report, at least for certain components, due to management or conservation concerns that are specific to those habitats.

 Consider future reports or analyses for the broader region (e.g., Marin County; San Francisco Bay Area) that could go beyond One Tam and be inclusive of the NPS Riparian Landbird

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monitoring effort at GGNRA, PRNS, and Pinnacles National Park, as well as monitoring at the Presidio of San Francisco and at the Palomarin Field Station (Gardali et al. 2010a, Porzig et al. 2011, Humple and Gardali 2015, and Humple et al. 2017).

 Consider any other data gaps and whether they might be, or become, of interest for long-term monitoring (e.g., urban areas; whether all agencies are proportionally represented). Further analyses, if of interest, could elucidate these gaps, and then an assessment of the potential to incorporate additional monitoring could be done.

This report, and the support for this effort, is a testament to the incredible work that is being done by agencies and partners within One Tam, and we acknowledge these agencies and institutions for their sound stewardship of Mount Tamalpais and its environs. Despite the many recommendations and considerations above, an important take-home is that we are generally in good shape to be able to assess the status and trends of birds in One Tam through a robust monitoring program. Additionally, if results from previous studies continue as they have (e.g., Cormier and Humple 2017), another testament are the generally stable populations we have observed. The continued long-term monitoring effort, especially once enhanced by some of the recommendations for additional monitoring provided above, will ensure that land managers and conservation science practitioners remain abreast of the status of the birds in the region. This will allow us to be poised to recognize when significant changes or declines occur that may require management action. We look forward to continuing the conversation of how best to incorporate some of the above recommendations into a broader monitoring program.

ACKNOWLEDGMENTS We thank the One Tam team for their effort to understand the avifauna of One Tam and to identify data gaps; Sharon Farrell, Janet Klein, Lizzie Edson, and Garrett Lee from GGNPC for their support of this overall endeavor; Lizzie Edson for providing vegetation layers; and Janet Klein for helping establish the MMWD monitoring project. We thank Sarah Minnick, Lisa Michl, and Serena Hubert (MCP) for guidance, support and help with access; Shaun Horne, Carl Sanders, and other MMWD staff for support; Catey Ritchie (GGNPC), Taylor Ellis and Lucy Scott (NPS), and Gwen Heistand (Audubon Canyon Ranch) for help with site access. We also are grateful to ; Bill Merkle from GOGA, and GGNPC, for their support of the Redwood Creek point count monitoring in 2019; private funders for supporting Redwood Creek monitoring in 2018; and Christina Freeman and Bree Hardcastle from California State Parks for permitting assistance in Mount Tamalpais State Park. At Point Blue, we thank Tom Gardali from Point Blue for helping develop this project and providing helpful guidance, including on future monitoring recommendations; Hilary Allen for help with site selection, conducting surveys, and reviewing the Methods section in this report; Renée Cormier for conducting surveys, for reviewing an earlier draft of this report, and for feedback on developing future monitoring recommendations; Megan Elrod for conducting surveys in 2018-19; Mark Dettling and Kristen Dybala for feedback on developing future monitoring recommendations; and various Point Blue biologists for establishing and conducting historic surveys. This is Point Blue Contribution # 2268.

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Appendix A. Bird species detected (including all distances and flyover detections) by Point Blue during point count surveys in 2018-19 in the One Tam region. Species list is arranged in taxonomic order and presence at either new grassland, historic revisited, or continuously monitored points is indicated by a dot under the respective category. California Partners in Flight grassland focal species are emboldened.

New Historic Continuously Species Grassland Revisited Monitored Code Common Name Scientific Name Points Points Points CANG Canada Goose Branta canadensis ● ● MALL Mallard Anas platyrhynchos ● ● COME Common Merganser Mergus merganser ● CAQU California Quail Callipepla californica ● ● ● WITU Wild Turkey Meleagris gallopavo ● ● ● COLO Common Loon Gavia immer ● ● PBGR Pied-billed Grebe Podilymbus podiceps ● DCCO Double-crested Cormorant Phalacrocorax auritus ● ● TUVU Turkey Vulture Cathartes aura ● ● OSPR Osprey Pandion haliaetus ● ● ● WTKI White-tailed Kite Elanus leucurus ● ● ● SSHA Sharp-shinned Hawk Accipiter striatus ● COHA Cooper's Hawk Accipiter cooperii ● RSHA Red-shouldered Hawk Buteo lineatus ● ● ● RTHA Red-tailed Hawk Buteo jamaicensis ● ● ● AMKE American Kestrel Falco sparverius ● VIRA Virginia Rail Rallus limicola ● KILL Killdeer Charadrius vociferus ● MAGO Marbled Godwit Limosa fedoa ● WEGU Western Gull Larus occidentalis ● CATE Caspian Tern Hydroprogne caspia ● ● ● BTPI Band-tailed Pigeon Patagioenas fasciata ● ● ● EUCD Eurasian Collared-Dove Streptopelia decaocto ● ● MODO Mourning Dove Zenaida macroura ● ● ● GHOW Great Horned Owl Bubo virginianus ● NOPO Northern Pygmy-Owl Glaucidium gnoma ● BADO Barred Owl Strix varia ● NSWO Northern Saw-whet Owl Aegolius acadicus ● WTSW White-throated Swift Aeronautes saxatalis ● ANHU Anna's Hummingbird Calypte anna ● ● ● ALHU Allen's Hummingbird Selasphorus sasin ● ● ● BEKI Belted Kingfisher Megaceryle alcyon ● ● ● ACWO Acorn Woodpecker Melanerpes formicivorus ● ● ● NUWO Nuttall's Woodpecker Picoides nuttallii ● ● ● DOWO Downy Woodpecker Picoides pubescens ● ● ● HAWO Hairy Woodpecker Picoides villosus ● ● ● NOFL Northern Flicker Colaptes auratus ● ● ● PIWO Pileated Woodpecker Dryocopus pileatus ● ● ● OSFL Olive-sided Flycatcher Contopus cooperi ● ● ● WEWP Western Wood-Pewee Contopus sordidulus ● ● PSFL Pacific-slope Flycatcher Empidonax difficilis ● ● ● BLPH Black Phoebe Sayornis nigricans ● ● ● ATFL Ash-throated Flycatcher Myiarchus cinerascens ● ● ●

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New Historic Continuously Species Grassland Revisited Monitored Code Common Name Scientific Name Points Points Points CAVI Cassin's Vireo Vireo cassinii ● ● HUVI Hutton's Vireo Vireo huttoni ● ● ● WAVI Warbling Vireo Vireo gilvus ● ● ● STJA Steller's Jay Cyanocitta stelleri ● ● ● CASJ California Scrub-Jay Aphelocoma californica ● ● ● AMCR American Crow Corvus brachyrhynchos ● ● ● CORA Common Raven Corvus corax ● ● ● HOLA Horned Lark Eremophila alpestris ● PUMA Purple Martin Progne subis ● ● ● TRES Tree Swallow Tachycineta bicolor ● ● VGSW Violet-green Swallow Tachycineta thalassina ● ● ● CLSW Cliff Swallow Petrochelidon pyrrhonota ● ● ● BARS Barn Swallow Hirundo rustica ● CBCH Chestnut-backed Chickadee Poecile rufescens ● ● ● OATI Oak Titmouse Baeolophus inornatus ● ● ● BUSH Bushtit Psaltriparus minimus ● ● ● RBNU Red-breasted Nuthatch Sitta canadensis ● ● ● WBNU White-breasted Nuthatch Sitta carolinensis ● ● ● PYNU Pygmy Nuthatch Sitta pygmaea ● ● ● BRCR Brown Creeper Certhia americana ● ● ● BEWR Bewick's Wren Thryomanes bewickii ● ● ● HOWR House Wren Troglodytes aedon ● PAWR Pacific Wren Troglodytes pacificus ● ● ● GCKI Golden-crowned Kinglet Regulus satrapa ● ● ● BGGN Blue-gray Gnatcatcher Polioptila caerulea ● ● WEBL Western Bluebird Sialia mexicana ● ● ● SWTH Swainson's Thrush Catharus ustulatus ● ● ● HETH Hermit Thrush Catharus guttatus ● ● ● AMRO American Robin Turdus migratorius ● ● ● WREN Wrentit Chamaea fasciata ● ● ● NOMO Northern Mockingbird Mimus polyglottos ● EUST European Starling Sturnus vulgaris ● ● CEDW Cedar Waxwing Bombycilla cedrorum ● ● OCWA Orange-crowned Warbler Oreothlypis celata ● ● ● YRWA Yellow-rumped Warbler Setophaga coronata ● ● ● BTYW Black-throated Gray Warbler Setophaga nigrescens ● ● TOWA Townsend's Warbler Setophaga townsendi ● HEWA Hermit Warbler Setophaga occidentalis ● ● ● MGWA MacGillivray's Warbler Geothlypis tolmiei ● COYE Common Yellowthroat Geothlypis trichas ● ● WIWA Wilson's Warbler Cardellina pusilla ● ● ● SPTO Spotted Towhee Pipilo maculatus ● ● ● CALT California Towhee Melozone crissalis ● ● ● RCSP Rufous-crowned Sparrow Aimophila ruficeps ● ● ● CHSP Chipping Sparrow Spizella passerina ● ● ● LASP Lark Sparrow Chondestes grammacus ● SAVS Savannah Sparrow Passerculus sandwichensis ● GRSP Grasshopper Sparrow Ammodramus savannarum ●

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New Historic Continuously Species Grassland Revisited Monitored Code Common Name Scientific Name Points Points Points SOSP Song Sparrow Melospiza melodia ● ● ● WCSP White-crowned Sparrow Zonotrichia leucophrys ● ● DEJU Dark-eyed Junco Junco hyemalis ● ● ● WETA Western Tanager Piranga ludoviciana ● ● BHGR Black-headed Grosbeak Pheucticus melanocephalus ● ● ● LAZB Lazuli Bunting Passerina amoena ● ● ● RWBL Red-winged Blackbird Agelaius phoeniceus ● ● ● BRBL Brewer's Blackbird Euphagus cyanocephalus ● ● ● BHCO Brown-headed Cowbird Molothrus ater ● ● ● BUOR Bullock's Oriole Icterus bullockii ● PUFI Purple Finch Haemorhous purpureus ● ● ● HOFI House Finch Haemorhous mexicanus ● ● ● RECR Red Crossbill Loxia curvirostra ● ● ● PISI Pine Siskin Spinus pinus ● ● ● LEGO Lesser Goldfinch Spinus psaltria ● ● ● AMGO American Goldfinch Spinus tristis ● ● ●

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Appendix B. Habitat cover within the One Tam region, survey coverage, and change in coverage by adding the new grassland points and historic revisited points in 2018-19. Wildlife Habitat Relationship (WHR) classes are grouped into general habitat types (in bold). ↔ = relatively no change in coverage; ↑ = 10-50% increase in coverage; ↑↑ = 50% or greater increase in coverage (note this does not take into account the subdominant habitat types also represented at points). One # of points Total points % of change in coverage Habitat Tam added in surveyed points by adding new + WHR Name Cover 2018-19 2018-19 (all) revisited Oak Woodland 26% 3 84 16% ↔ Coastal Oak Woodland 22% 3 79 15% ↔ Montane Hardwood 4% 5 1% ↔ Valley Oak Woodland 0.01% Other Conifer 19% 25 108 20% ↑ Douglas Fir 16% 25 107 20% ↑ Montane Hardwood-Conifer 2% Closed-Cone Pine-Cypress 0.90% 1 0.20% ↔ Undetermined Conifer 0.01% Redwood 15% 33 94 17% ↑ Grassland1 10% 102 129 23% ↑↑ Annual Grassland1 9% 100 126 23% ↑↑ Perennial Grassland 0.80% 2 3 0.01% ↑↑ Pasture 0.40% Coastal Scrub 9% 19 19 4% ↑↑ Chaparral 9% 80 14% ↔ Mixed Chaparral 8% 77 14% ↔ Chamise-Redshank Chaparral 0.60% 1 0.20% ↔ Urban 7% 2 0.40% ↑ Riparian2 0.4% 24 4% ↔ Valley Foothill Riparian2 0.30% 24 4% ↔ Montane Riparian 0.10% Other 7% 8 14 2% ↑↑ Lacustrine 2% 4 1% ↔ Water 2% Barren 1.20% Eucalyptus 0.70% 8 8 1% ↑↑ Saline Emergent Wetland 0.30% Fresh Emergent Wetland 0.20% 2 0.40% ↔ Marsh 0.04% Dryland Grain Crops 0.01% Undetermined Hardwood <0.01% Undetermined Shrub 0.01% Vineyard <0.01% Wet Meadow 0.01%

1Continuous and historic points that were classified as “grassland” per the habitat coverage assessment were predominantly associated with small disjunct grassland patches and did not necessarily meet site selection criteria that were used for selecting new grassland points. 2Valley foothill riparian was assigned to all points in the Redwood Creek riparian transect regardless of the dominant habitat within a 100 m radius.

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Appendix C. Assessing coverage and habitat by point across all point count stations surveyed by Point Blue in 2018-19 in the One Tam region: tally of points according to the dominant vegetation type (WHR = wildlife habitat relationship) within 100 m radius of each point. C = continuously monitored points, H = historic revisited points, and N = new grassland points.

MCP MMWD NPS CSP Private Total Points WHR Name C H N C H N C H N C H N C H N C H N All Annual Grassland 8 6 18 23 1 6 44 7 13 261 141 86 1261 Perennial Grassland 1 2 11 2 3 Total Grassland Habitat1 27 14 88 1291 Douglas Fir 2 77 12 3 10 3 82 25 107 Redwood 2 47 12 29 4 61 33 94 Coastal Oak Woodland 5 73 2 1 78 3 81 Mixed Chaparral 4 67 4 1 1 77 77 Coastal Scrub 11 8 19 19 Eucalyptus 8 8 8 Montane Hardwood 5 5 5 Lacustrine 4 4 4 Valley Foothill Riparian2 10 14 242 242 Urban 1 1 1 Chamise-Redshank Chaparral 1 1 1 Closed-Cone Pine-Cypress 1 1 1 Total 13 8 6 295 0 25 27 68 44 25 15 13 1 11 0 361 102 88 551 1Continuous and historic points that were classified as “grassland” per the habitat coverage assessment were predominantly associated with small disjunct grassland patches and did not necessarily meet site selection criteria that were used for selecting new grassland points. 2Valley foothill riparian was assigned to all points in the Redwood Creek riparian transect regardless of the dominant habitat within a 100 m radius.

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Supplement A: Point Count Transect Site Narratives

Separate document; available Upon Request

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