INTRODUCTION AND BACKGROUND

Transcription

1 2014 Annual Report to U.S. Fish and Wildlife Service: California Ridgway s Rail (Rallus obsoletus obsoletus) TE Submitted to U.S. Fish and Wildlife Service, Sacramento October, 2014 Submitted by Point Blue Conservation Science Julian Wood, Megan Elrod Point Blue Conservation Science, 3820 Cypress Drive #11, Petaluma, CA Contact: jwood@pointblue.org INTRODUCTION AND BACKGROUND The California Ridgway s Rail (Rallus obsoletus obsoletus; formerly California Clapper Rail and hereafter RIRA), is one of the most endangered species in California. The species is dependent on tidal wetlands, which have decreased over 75% from the historical extent in San Francisco Bay. A complete survey of the RIRA population and distribution within the San Francisco Bay Estuary began in In 2014, Point Blue Conservation Science (formerly PRBO) completed the tenth year of field work designed to improve Estuary-wide population estimates, determine trends in abundance, and identify important habitat and landscape features for the RIRA. Field work was performed in agreement with the State Coastal Conservancy s Invasive Spartina Project (ISP) and the Baywide survey effort was coordinated through the ISP. Collaboration with other partners conducting call-count surveys included Avocet Research Associates (ARA), California Department of Fish and Wildlife (CDFW), and U.S. Fish and Wildlife Service (USFWS). This report summarizes Point Blue s California Ridgway s Rail surveys in 2014 under U.S. Fish and Wildlife service permit TE The summary numbers presented in this report are designed to describe our field effort and unique detections of RIRA. The raw total number of birds presented should not be interpreted as site-level or Baywide population estimates. Nor should the apparent differences among years be used to determine a trend. In addition, RIRA are notoriously difficult to detect, which results in many false zeroes in a given dataset, consequently impacting an attempt to tally RIRA numbers at different spatial

2 P a g e 1 scales. Therefore, to investigate RIRA trends in the Estuary, we encourage a thorough analysis, as Point Blue has demonstrated in our previous reports (Liu et al 2012). In previous years ( ), Point Blue received funding to compile and analyze data from all agencies and organizations participating in standardized Baywide RIRA surveys. The final results from this collaborative project are detailed in Liu et al (2012). Beginning in 2012, Point Blue only received funding to conduct surveys and not to integrate and analyze data from multiple contributors. Point Blue has, however, entered in a collaborative agreement with the Inventory and Monitoring Program of the USFWS. An initial product was to analyze the previous paired survey effort ( ), investigating the use of the North American Secretive Marshbird Protocol (Conway 2011) in the Estuary. Those results were compiled in a report to the I&M Program (Wood et al 2014). Conclusions from those reports, and Point Blue s commitment to furthering a decade long dataset, is to encourage the need for monitoring, in order to efficiently obtain population estimates which inform adaptive management decisions that support robust RIRA populations in the Bay. No nests were incidentally discovered during surveys, nor were any Ridgway s Rails harmed or killed. METHODS Type A call-count surveys were conducted from 15 January 2014 to 4 April Point Blue surveyed 31 marsh sites in the Estuary; 18 sites were in San Pablo Bay, 7 sites in Central San Francisco Bay, and 6 sites in South San Francisco Bay (Table 1, Figures 1a-g). Sites were surveyed three times by experienced permitted biologists, using a point transect method with 10 minutes per survey station. Survey stations were located primarily at marsh edges, levees bordering and within marshes, boardwalks, and boat-accessible channels within the marsh. Stations were placed m apart. Station locations (x, y coordinates) surveyed in 2014 are presented in Table 2. All RIRA, as well as California Black Rail (Laterallus jamaicencis coturniculus), Virginia Rail (Rallus limicola), and Sora (Porzana carolina), detected from a survey station were recorded along with the time, direction and distance from the survey station. The actual number of rails detected was recorded, or if the detection was not heard clearly because of confounding circumstances (e.g., distance from observer or environmental conditions) a range in number of rails (e.g., 1 to 2, 2 to 4) was recorded. Playback (up to 1 minute) of RIRA vocalizations (kek, clatter, and kekburr calls) were used to stimulate a response at minute six of the third survey only under certain conditions: If no RIRA were detected, incidentally or during a 10-minute survey, from a survey station (regardless of distance from observer) AND no RIRA were detected near that station (within 200 m) after the first two passive surveys. Third round playback surveys consisted of 5 minutes of passive listening, then 1 minute of playback (if no RIRA detected), followed by another 4 minutes of passive listening. Playback was immediately stopped by the observer upon hearing a RIRA. RIRA detected during transit between listening stations as well

3 P a g e 2 as before or after the 10-minute listening period were also recorded and summarized in this report. We summarized our 2014 data by selecting the survey visit with the greatest number of minimum unique RIRA detections, which also includes any unique detections made outside of the official 10-minute survey period. For example, if on the first visit to a marsh the observer recorded 10 to 12 individuals, on the second visit recorded 14 to 16, and on the third visit recorded 8 to 10, the second visit would be the highest count (14 16) and the lower number of the reported range (14) would be used as the site estimate. This is referred to as the highest minimum count for a given site. RESULTS AND DISCUSSION Point Blue Conservation Science biologists documented RIRA at 30 marsh sites (Table 1). Effort was increased in 2014 from 2013 when only a minimum of sites were surveyed by Point Blue biologists, and therefore many sites are discussed in comparison to 2012 counts or to the last season in which the site was visited. Prior to 2013, the population had maintained a stable to upward trend following the dramatic drop between 2007 and 2008 (Liu et. al. 2012). The sites that were surveyed in 2013 suggested a slight overall decrease in RIRA, except for a few notable exceptions showed a potential rebound in numbers. Most sites surveyed in 2014 had numbers comparable to 2012, when the RIRA trend was stable or slightly positive. San Pablo Bay China Camp State Park and the Gallinas Creek Complex Detections of RIRA continue to fluctuate annually at China Camp marsh. Beginning with a minimum of 11 detected in 2010, numbers grew to a high of 32 in 2012, a drop in 2013 down to 16, then back to 28 individuals in Gallinas Creek North (Hamilton South), has had 30 to 40 individuals since 2010, and remained within that range in 2014 at 37. McInnis Marsh, to the south, which has had between 40 and 50 RIRA since 2010, remained stable from 2013 and within the normal range in 2014, at 49 individuals. Santa Venetia Marsh alone is a small marsh parcel, but the stations also survey the lower reaches of Gallinas Creek, including an eastern section of McInnis Marsh. The survey from Santa Venetia stations added an additional 29 unique individuals in 2014 to the already robust numbers for the complex. Overall the Gallinas Creek Complex, including China Camp State Park to the south, continues to support some of the highest numbers of RIRA in the Bay.

4 P a g e 3 Petaluma River Complex A total of 62 RIRA were detected at sites surveyed in the Petaluma River complex, from Black John Slough to the north, to the southern section of the river mouth along Novato Creek. In the extensive ancient marsh complex, every marsh parcel is not surveyed annually by Point Blue; with a few exceptions, including Black John Slough North. While there has been a slight decrease since the high count of 16 in 2010, since then there have consistently been 10 to 13 individuals recorded. In 2014, 10 unique individuals were recorded at Black John Slough North. The Greenpoint Marshes, which includes centennial and restored marsh sections, were not surveyed in 2013, but in 2011 and 2012 a total of 22 individuals were recorded, and in 2014 a total of 20 birds were detected. Carl s Marsh, now a 20 year old restoration, has consistently recorded 8 individuals on surveys since 2010, with the exception of a high count of 14 in During the 2014 surveys, 8 RIRA were recorded. At the Petaluma River Mouth, including the restored section of Sonoma Baylands to the north, Point Blue recorded 6 RIRA in 2014, compared to 4 in Novato Creek Mouth numbers have fluctuated more in the last 5 years than other sites along the Petaluma River, with only 5 individuals recorded in 2014, down from the high count of 19 in However, numbers jumped at this site between 2010 and 2011 as well, which went from 8 to 16 individuals respectively. Richmond/Pinole complex The total number of detections along the north Richmond shoreline continued to increase in 2014, with 66 unique RIRA, doubling the total number from At Wildcat Marsh north alone, 31 individuals were counted in 2014, from a low of 6 in 2011, and up from 17 in Richmond Fragment had a count of 22 in 2010, a decline to a low of 12 individuals in 2013, but showed a large increase in 2014, up to a high count of 33 unique individuals was also the first year that Point Blue recorded birds in the southern portion of Wildcat Marsh (Castro Creek). Central San Francisco Bay Corte Madera Ecological Reserve The focus of the surveys around Central San Francisco Bay (Bay Bridge to Pt. San Pedro/Pt. San Pablo), remained centered on the Corte Madera Ecological Reserve. Seven sites were surveyed covering the region in 2014, which continues to provide suitable habitat, despite annual RIRA fluctuations recorded in the last few years. Heerdt Marsh detections decreased from 32

5 P a g e 4 detections in 2012 to 20 unique individuals in 2013, but increased to 44 in 2014, equaling the number recorded in Muzzi Marsh surveys resulted in 21 individuals in 2014, up from a low of 15 in 2013, but still not close to the high count of 42 in Corte Madera Creek and Richardson Bay Upstream on Corte Madera Creek at Piper Park, previous surveys in this small marsh parcel yielded 12 individuals in 2010 and 2011, however only 4 RIRA were detected in Further south in the region, the Bothin Marsh/Tam High Fragment has supported 2 to 5 individuals in the last 5 years and 2 were recorded in South San Francisco Bay Faber-Laumeister Detections at Faber-Laumeister increased from 50 detections in 2013 to 78 in 2014, still lower than in 2011 and 2012 when rail detections reach 94 and 91, respectively. The Faber Tract doubled the count from 2013, going from 25 to 50, closer to the high count of 69 individuals in Over the last five years, counts at Laumeister have remained slightly more stable, ranging from 17 to 30, with 32 recorded in Palo Alto Baylands RIRA detections at Palo Alto Baylands remained stable in 2014 with 14 detected, but is still reduced compared to the 20 detections in At the adjacent Palo Alto Harbor/Hooks Island site, detections showed a slight increase from 15 in 2013 to 18, the highest count at the site in the last 5 years. Dumbarton and Audubon Marshes Point Blue returned in 2014 to survey Dumbarton East, including the Audubon Marsh, east of Newark Slough. The most recent prior count was in 2010, when 4 birds were recorded in Audubon Marsh. In 2014, 8 birds were recorded, 7 in Audubon and 1 in Dumbarton East.

6 P a g e 5 Suggested Citation: Elrod, M., J. Wood, X. Castaneda California Ridgway s Rail (Rallus obsoletus obsoletus) 2014 Survey Report. TE Report to the Invasive Spartina Project of the State Coastal Conservancy. References Conway, C. J Standardized North American Marsh Bird Monitoring Protocol. Waterbirds 34(3): doi: / Liu, L., J. Wood, N. Nur, L. Salas, and D. Jongsomjit California Clapper Rail (Rallus longirostris obsoletus) Population monitoring: PRBO Technical Report to the California Department of Fish and Game. Wood, J., L. Salas, N. Nur, M. Elrod Secretive Marsh Bird Survey Protocol Comparison in San Francisco Bay. Report to USFWS Division of Refuges Inventory and Monitoring Program, Sacramento, CA. Wood, J., X. Castaneda, M. Elrod, N. Nur Annual Report to U.S. Fish and Wildlife Service: California Clapper Rail (Rallus longirostris obsoletus). Report to USFWS, Sacramento, CA. Acknowledgements Data were collected under TE from USFWS and a Memorandum of Understanding between CDFW and Point Blue (8/1/2012) with funding from the State Coastal Conservancy s Invasive Spartina Project (ISP). During 2014 surveys, along with the ISP, Point Blue benefited greatly from collaboration with a number of other organizations and agencies: U.S. Fish and Wildlife Service, Don Edwards San Francisco Bay National Wildlife Refuge, San Pablo Bay National Wildlife Refuge, California Department of Fish and Game, California Department of Parks and Recreation, City of Palo Alto, and the City of Petaluma.

7 P a g e 6 Table 1. RIRA Survey Results Summary Highest minimum number of RIRA by site from three rounds of Point Blue 2014 surveys. Bay Region Complex Site Name San Pablo Bay Central San Francisco Bay South Bay Petaluma River (North to South) Richmond Pinole Gallinas Creek Survey Date with Highest Min. Count Highest Min. Count Tule Slough 3/21 8 Woloki Slough 2/7 2 Black John Slough north 2/21 10 Green Point Centennial 3/6 7 Green Point Strip Marsh 3/6 5 Green Point Restoration 3/6 8 Petaluma R. East Strip 2/21 1 Carl's Marsh 2/14 8 Petaluma River Mouth 2/21 6 Day Island Wildlife Area 4/2 2 Novato Creek Mouth N&S 4/2 5 Wildcat Marsh N/Castro Creek 2/24 31 Wildcat Marsh S/Castro Creek 4/8 2 San Pablo Creek 1/21 33 China Camp 2/14 28 Santa Venetia 2/12 29 Mitchell Fragment 2/24 3 McInnis Marsh 3/3 49 Gallinas Creek North 2/18 37 Richardson Bay Bothin Marsh/Tam High Fragment 3/10 2 Heerdt Marsh 2/10 44 Greenbrae Boardwalk 2/10 4 Corte Madera Marta's Marsh 2/13 3 Ecological Reserve Muzzi Marsh 2/13 21 San Clemente Creek 2/13 2 Corte Madera Piper Park 2/27 4 Corte Madera Creek Mouth 2/10 1 Dumbarton Dumbarton Marsh East 2/18 1 Audubon Marsh East 2/18 7 East Palo Alto Palo Alto Baylands Faber Marsh 1/29 50 Laumeister Marsh 3/4 32 Palo Alto Baylands 1/28 14 Palo Alto Harbor/Hook Island 1/28 18 Charleston Slough --- 0