Yiwei Wang

EDEN LANDING ECOLOGICAL RESERVE PILOT STUDY ON PREDATORS OF WESTERN SNOWY PLOVERS AND CALIFORNIA LEAST TERNS FINAL REPORT

Dave Halsing — Mon, 04 Mar 2024 15:30:51 +0000

EDEN LANDING ECOLOGICAL RESERVE PILOT STUDY ON PREDATORS OF WESTERN SNOWY PLOVERS AND CALIFORNIA LEAST TERNS FINAL REPORT Dave Halsing Mon, 03/04/2024 - 07:30

Document Category

Scientific Reports

Author(s)

Date

2024-02

Summary

The objectives of this study were to 1) determine whether avian and mammalian predator activity, density, and space use can be successfully detected and quantified using camera traps, 2) employ multiple field techniques to estimate the activity, density, and space use of the array of species that depredate snowy plovers, comprising both birds and mammals, 3) make a preliminary determination of the effect of predator removal on predation rates using camera-trap derived estimations in combination with existing data, and 4) conduct preliminary testing of 1-2 additional methods of predator management (i.e., fencing and raptor nest relocation) and measuring subsequent responses, if any, in predator activity and predation rates.

Keywords

western snowy plover

least tern

predation

Pond Complex

Eden Landing

Habitat Use by Breeding Waterbirds in Relation to Tidal Marsh Restoration in the San Francisco Bay Estuary

ariela — Tue, 27 Jun 2023 18:27:53 +0000

Habitat Use by Breeding Waterbirds in Relation to Tidal Marsh Restoration in the San Francisco Bay Estuary

Map of 2019 avocet observations

ariela Tue, 06/27/2023 - 11:27

Document Category

Scientific Reports

Author(s)

Date

2023-06

Summary

Abstract

The South Bay Salt Pond Restoration Project aims to restore many former salt production ponds, now managed for wildlife and water quality, to tidal marsh. However, because managed ponds support large densities of breeding waterbirds, reduction of pond habitat may influence breeding waterbird distribution and abundance. We investigated habitat use associated with breeding, feeding, and roosting behaviors during the breeding season for American Avocets (Recurvirostra americana), Black-necked Stilts (Himantopus mexicanus), Forster’s Terns (Sterna forsteri), and Caspian Terns (Hydroprogne caspia) in south San Francisco Bay in 2019 after substantial tidal marsh restoration, and compared results to a 2001 survey (before restoration). In 2019, managed ponds (26% of currently available habitat) were selected by waterbirds engaged in breeding behaviors (> 39% of observations), foraging (> 42%), and roosting (> 73%). Waterbirds avoided tidal habitats (43% of available habitat), comprising < 17% of observations of breeding behavior, < 28% of foraging observations, and < 13% of roosting observations. Waterbird densities increased in managed ponds between 2001 and 2019, and decreased in active salt ponds, especially among feeding Avocets (92% decrease) and Stilts (100% decrease). Islands were important for waterbirds observed breeding and roosting (45% of Avocet and 53% of Tern observations). Avocets and Stilts fed primarily on wet bare ground (65% and 58%, respectively), whereas feeding Forster’s Terns and Caspian Terns used mostly open water (82% and 93%, respectively). Within ponds, Avocets were associated with islands (131 m closer than expected). Stilts and Forster’s Terns were also associated with islands (68 m and 161 m closer than expected), except when feeding (1 m closer and 90 m farther than expected). Avocets and Stilts were associated with pond levees (39 m and 41 m closer than expected), but Forster’s Terns were not (9 m closer than expected). Our results emphasize the importance of managed ponds for breeding and foraging waterbirds, including islands for breeding and roosting and levees for foraging.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Content available here

eScholarship link to paper

Western Snowy Plover Monitoring in the San Francisco Bay Annual Report 2021

ariela — Fri, 18 Mar 2022 00:40:28 +0000

Western Snowy Plover Monitoring in the San Francisco Bay Annual Report 2021

Banded snowy plover chick in depression with oyster shell. Credit: SFBBO

ariela Thu, 03/17/2022 - 17:40

Document Category

Scientific Reports

Author(s)

Date

2022-02

Summary

The San Francisco Bay Bird Observatory (SFBBO), USFWS Don Edwards San Francisco Bay National Wildlife Refuge (Refuge), California Department of Fish and Wildlife (CDFW), Hayward Area Recreation and Park District (HARD), East Bay Regional Park District (EBRPD), USFWS Bay Delta Fish and Wildlife Office, USDA-Wildlife Services, and Vollmar Natural Lands Consulting form the Western Snowy Plover (Charadrius nivosus nivosus; Snowy Plover) Recovery Unit 3 working group. The goal of this collaboration is to survey managed ponds and other habitats for Snowy Plovers, track breeding success, and contribute to the management and recovery of this species in the San Francisco Bay. During the 2022 breeding season, SFBBO monitored Snowy Plover population size, nesting and fledging success, the use of experimental habitat enhancement sites, and potential predators.

As part of the Pacific Coast breeding season window survey (May 16-22), we counted 263 adult Snowy Plovers in the San Francisco Bay. Over the course of the breeding season (March-September), SFBBO staff determined and documented the fates of 209 Snowy Plover nests in Recovery Unit 3, with 207 located in the South Bay and two located in San Pablo Bay. EBPRD documented the fate of three Snowy Plover nests at Hayward Shoreline. Vollmar Consulting Biologists documented the fate of two nests at Montezuma Wetlands in Suisun Bay near the Sacramento-San Joaquin Delta. Of the total nests, 48% were depredated, 3% abandoned, 2% unknown, 1% flooded, and 1% failed to hatch. Apparent nest success (defined as the percentage of nests that successfully hatched at least one egg out of the total nests monitored) was 45%.

Keywords

bird eggs

birds

nesting density

habitat characteristics

Pond Complex

Alviso

Eden Landing

Ravenswood

Breeding Waterbird Populations Have Declined in South San Francisco Bay: An Assessment Over Two Decades

ariela — Tue, 28 Sep 2021 17:03:30 +0000

Breeding Waterbird Populations Have Declined in South San Francisco Bay: An Assessment Over Two Decades ariela Tue, 09/28/2021 - 10:03

Document Category

Scientific Reports

Author(s)

Date

2021-09

Summary

In south San Francisco Bay, former salt ponds now managed as wildlife habitat support large populations of breeding waterbirds. In 2006, the South Bay Salt Pond Restoration Project began the process of converting 50% to 90% of these managed pond habitats into tidal marsh. We compared American Avocet (Recurvirostra americana) and Black-necked Stilt (Himantopus mexicanus) abundance in south San Francisco Bay before (2001) and after approximately 1,300 ha of managed ponds were breached to tidal action to begin tidal marsh restoration (2019). Over the 18-year period, American Avocet abundance declined 13.5% (2,765 in 2001 vs. 2,391 in 2019), and Black-necked Stilt abundance declined 30.0% (1,184 in 2001 vs. 828 in 2019). Forster’s Tern (Sterna forsteri) abundance was 2,675 birds in 2019. In 2019, managed ponds accounted for only 25.8% of suitable habitats, yet contained 53.9%, 38.6%, and 65.6% American Avocet, Black-necked Stilt, and Forster’s Tern observations, respectively. Conversely, tidal marsh and tidal mudflats accounted for 42.9% of suitable habitats, yet contained only 18.4%, 10.3%, and 19.8% of American Avocet, Black-necked Stilt, and Forster’s Tern observations, respectively. Using a separate nest-monitoring data set, we found that nest abundance in south San Francisco Bay declined for all three species from 2005–2019. Average annual nest abundance during 2017–2019 declined 53%, 71%, and 36%, for American Avocets, Back-necked Stilts, and Forster’s Terns, respectively, compared to 2005–2007. Loss of island nesting habitat as a result of tidal marsh conversion and an increasing population of predatory California Gulls (Larus californicus) are two potential causes of these declines. All three species established nesting colonies on newly constructed islands within remaining managed ponds; however, these new colonies did not make up for the steep declines observed at other historical nesting sites. For future wetland restoration, retaining more managed ponds that contain islands suitable for nesting may help to limit further declines in breeding waterbird populations.

Hartman, C. A, Ackerman, J. T, Schacter, C. R, Herzog, M. P, Tarjan, L. M, Wang, Y., et al. (2021). Breeding Waterbird Populations Have Declined in South San Francisco Bay: An Assessment Over Two Decades. San Francisco Estuary and Watershed Science, 19(3). http://dx.doi.org/10.15447/sfews.2021v19iss3art4 Retrieved from https://escholarship.org/uc/item/16n259mc

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Content available here

San Francisco Estuary and Watershed Science, Volume 19, Issue 3

Establishing Forster’s Tern (Sterna forsteri) Nesting Sites at Pond A16 Using Social Attraction for the South Bay Salt Pond Restoration Project

ariela — Mon, 10 Aug 2020 18:52:54 +0000

Establishing Forster’s Tern (Sterna forsteri) Nesting Sites at Pond A16 Using Social Attraction for the South Bay Salt Pond Restoration Project

Cover of Forster's tern report

ariela Mon, 08/10/2020 - 11:52

Document Category

Scientific Reports

Author(s)

Date

2020-07

Summary

Abstract

Forster’s terns (Sterna forsteri), historically one of the most numerous colonial-breeding waterbirds in South San Francisco Bay, California, have experienced recent decreases in the number of nesting colonies and overall breeding population size. The South Bay Salt Pond Restoration Project aims to restore 50–90 percent of former salt evaporation ponds to tidal marsh habitat in South San Francisco Bay. During phase 1 of the South Bay Salt Pond Restoration Project, the breaching of several pond levees to begin the process of tidal marsh restoration inundated island nesting habitat that had been used by Forster’s terns, American avocets (Recurvirostra americana), and other waterbirds. Additional nesting habitat could be lost as more managed ponds are converted to tidal marsh in the future. To address this issue, the South Bay Salt Pond Restoration Project organized the construction of new nesting islands in managed ponds that will not be restored to tidal marsh, thereby providing enduring island nesting habitat for waterbirds. In 2012, 16 new islands were constructed in Pond A16 in the Alviso complex of the Don Edwards San Francisco Bay National Wildlife Refuge, which increased the number of islands in this pond from 4 to 20. However, despite a long history of nesting on the four islands in Pond A16 before the 2012 construction activities, no Forster’s terns have nested in Pond A16 during the 7-year period (2012–18) after island construction.

During the 2017 and 2019 breeding seasons, we used social attraction measures (decoys and colony call playback systems) to attract Forster’s terns to islands within Pond A16 to re-establish nesting colonies. We maintained these systems from March through August in each year. To evaluate the effect of these social attraction measures, we completed surveys (between April and August) where we recorded the number and location of all Forster’s terns and other waterbirds using Pond A16, and we monitored waterbird nests. We compared bird survey and nest monitoring data collected in 2017 and 2019 to data collected in 2015 and 2016, prior to the implementation of social attraction measures, allowing for direct evaluation of the effect of social attraction efforts on Forster’s terns.

To increase the visibility and stakeholder involvement of this project, we engaged in multiple outreach activities in 2017, 2019, and 2020, including the development of a project website and educational video; publication of popular articles in 2017 and 2020; the development of outreach materials describing the project to the general public; and public presentations to relay findings to managers, stakeholders, and the general public.

The relative abundance of Forster’s terns in Pond A16, after adjusting for the overall South San Francisco Bay breeding population each year, was higher during the nesting period in 2017 and 2019 (when social attraction was used) than in 2015 and 2016 (before social attraction was used). Furthermore, more Forster’s terns were observed during the pre-nesting and nesting periods in the areas of Pond A16 where decoys and call systems were deployed. Although no Forster’s tern nests were observed in Pond A16 before social attraction was implemented (2015, 2016), or during the first-year social attraction was implemented (2017), 35 Forster’s tern nests were recorded during the second year of social attraction implementation in 2019. These 35 nests represent a re-establishment of a Forster’s tern nesting colony to Pond A16 for the first time in 8 years. As social attraction efforts often benefit from multiple years of decoy and call system deployment, results from 2017 and 2019 suggest that continued implementation of social attraction measures could help to ensure Forster’s tern breeding colonies persist in Pond A16 and other areas of South San Francisco Bay.

Suggested Citation

Hartman, C.A., Ackerman, J.T., Herzog, M.P., Wang, Y., and Strong, C., 2020, Establishing Forster’s Tern (Sterna forsteri) nesting sites at pond A16 using social attraction for the South Bay Salt Pond restoration project: U.S. Geological Survey Open-File Report 2020–1081, 28 p., https://doi.org/10.3133/ofr20201081.

ISSN: 2331-1258 (online)

Keywords

Pond Complex

Alviso

Evaluation of social attraction measures to establish Forster's tern (Sterna forsteri) nesting colonies for the South Bay Salt Pond Restoration Project, San Francisco Bay, California--2017 Annual Report

Dave Halsing — Wed, 22 Jan 2020 21:05:37 +0000

Evaluation of social attraction measures to establish Forster's tern (Sterna forsteri) nesting colonies for the South Bay Salt Pond Restoration Project, San Francisco Bay, California--2017 Annual Report Dave Halsing Wed, 01/22/2020 - 13:05

Document Category

Scientific Reports

Author(s)

Date

2018-05-31

Keywords

Forster’s tern

social attraction

nesting density

Pond Complex

Alviso

Content available here

USGS Publications

Migration Timing and Spatial Distribution of Phalaropes in South San Franicsco Bay

Biruk — Fri, 01 Nov 2019 19:32:50 +0000

Migration Timing and Spatial Distribution of Phalaropes in South San Franicsco Bay

Biruk Fri, 11/01/2019 - 12:32

Presentation

Author(s)

Susan E. W. De la Cruz

Migration Timing and Spatial Distribution of Phalaropes in South San Franicsco Bay

Biruk — Fri, 01 Nov 2019 19:28:39 +0000

Migration Timing and Spatial Distribution of Phalaropes in South San Franicsco Bay Biruk Fri, 11/01/2019 - 12:28

Document Category

Scientific Reports

Author(s)

Susan E. W. De la Cruz

Date

2019

Pond Complex

Eden Landing

Trends and habitat associations of waterbirds using the South Bay Salt Pond Restoration Project, San Francisco Bay, California: U.S. Geological Survey Open-File Report 2018–1040

Biruk — Fri, 11 May 2018 17:59:54 +0000

Trends and habitat associations of waterbirds using the South Bay Salt Pond Restoration Project, San Francisco Bay, California: U.S. Geological Survey Open-File Report 2018–1040

Cover of report.

Biruk Fri, 05/11/2018 - 10:59

Document Category

Scientific Reports

Author(s)

Susan E. W. De la Cruz

Date

2018

Summary

The aim of the South Bay Salt Pond Restoration Project is to restore 50–90 percent of former salt evaporation ponds to tidal marsh in San Francisco Bay. However, hundreds of thousands of waterbirds use these ponds over winter and during fall and spring migration. To ensure that existing waterbird populations are supported while tidal marsh is restored in the Project area, managers plan to enhance the habitat suitability of ponds by adding islands and berms to change pond topography, manipulating water salinity and depth, and selecting appropriate ponds to maintain for birds. To help inform these actions, we used 13 years of monthly (October–April) bird abundance data from Project ponds to (1) assess trends in waterbird abundance since the inception of the Project, and (2) evaluate which pond habitat characteristics were associated with highest abundances of different avian guilds and species. For comparison, we also evaluated waterbird abundance trends in active salt production ponds using 10 years of monthly survey data.

We assessed bird guild and species abundance trends through time, and created separate trend curves for Project and salt production ponds using data from every pond that was counted in a year. We divided abundance data into three seasons—fall (October–November), winter (December–February), and spring (March–April). We used the resulting curves to assess which periods had the highest bird abundance and to identify increasing or decreasing trends for each guild and species.

Keywords

roosting

waterbird abundance

habitat characteristics

Content available here

https://pubs.er.usgs.gov/publication/ofr20181040

Oyster Shell Habitat Enhancement for Breeding Snowy Plovers in Pond E14, Eden Landing Ecological Reserve, 2015

admin — Thu, 23 Nov 2017 00:21:53 +0000

Oyster Shell Habitat Enhancement for Breeding Snowy Plovers in Pond E14, Eden Landing Ecological Reserve, 2015 admin Wed, 11/22/2017 - 16:21

Document Category

Scientific Reports

Author(s)

Date

2016-02-01

Summary

From 2008 to 2014, SFBBO conducted a pilot study investigating the effects of oyster shell habitat enhancement on Snowy Plover nesting success. One hectare test plots were distributed on salt pond bottoms in Eden Landing Ecological Reserve (Eden Landing), Hayward, California. Data from this pilot study indicated that oyster shells may provide beneficial cover for nesting Snowy Plovers and suggest further breeding benefits on a larger scale. In October 2014 and through funding from Ducks Unlimited, two large oyster shell enhancement plots were distributed in pond E14, Eden Landing; non-shelled areas acted as controls. During the 2015 breeding season, SFBBO monitored Snowy Plover adults, nests, chicks, predatory species and activity, and biotic and abiotic soil characteristics of all areas within E14.

Keywords