Caitlin W. Robinson-Nilsen

Cargill Salt Pond Waterbird Surveys Report, October 2008 - September 2009

Josh Scullen

Date

2009-12-01

Summary

The San Francisco Bay Bird Observatory surveyed 22 salt evaporation ponds for waterbirds and sampled water quality from October 2008 through September 2009. The salt ponds surveyed are owned by the Don Edwards San Francisco Bay National Wildlife Refuge and managed for salt production by Cargill Salt. We examined species richness, total abundance within and between complexes. We also examined the difference in abundance of foraging guilds within each complex.

We observed 421,939 birds during our monthly surveys between October 2008 and September 2009. Species richness was greatest in Coyote Hills and Mowry complexes and lowest in the Dumbarton complex. Total abundance was highest in the Mowry complex, followed by Coyote Hills, then Dumbarton. The proportion of birds foraging was greatest in Coyote Hills and Dumbarton complexes, whereas birds mostly roosted in the Mowry complex.

We found that guilds were most abundant in specific ponds and water quality parameters often dictated guild-specific distributions. These distributions were likely driven by the prey distribution and the conditions needed for their survival. For example, we rarely found fish eaters in high salinity ponds because fish species cannot tolerate those salinities. Likewise, we often observed Eared Grebes, phalaropes, and shorebirds in high salinity ponds where brine shrimp and flies are likely abundant. Shorebird abundance is also dependent upon appropriate water depth for foraging and islands for roosting.

As the South Bay Salt Pond Restoration Project progresses, we recommend management of salt pond habitats to retain bird populations by maintaining a variety of water salinities for the guilds. Special consideration should be given to birds that prefer medium to high salinity ponds such as phalaropes and Eared Grebes. We also suggest providing lower water levels in some ponds for small and medium shorebirds during migration, and creating or maintaining islands or undisturbed levees for shorebird roosting habitat. Finally, as the restoration progresses, continuing to monitor avian use of these ponds will allow for managers to assess the success of the restoration in maintaining current bird populations.

Pond Complex

Alviso

Ravenswood

Content available here

Western Snowy Plover Numbers, Nesting Success, Fledging Success and Avian Predator Surveys in the San Francisco Bay, 2009

admin — Tue, 14 Nov 2023 21:33:41 +0000

Western Snowy Plover Numbers, Nesting Success, Fledging Success and Avian Predator Surveys in the San Francisco Bay, 2009 admin Tue, 11/14/2023 - 13:33

Document Category

Monitoring Reports

Author(s)

Western Snowy Plover Monitoring, 2009

Cheryl M. Strong

Date

2009-11-18

Summary

The San Francisco Bay Bird Observatory (SFBBO), Don Edwards San Francisco Bay National Wildlife Refuge (Refuge), California Department of Fish and Game (CDFG), Hayward Area Recreational and Park District (HARD), and East Bay Regional Parks District (EBRPD) form the Western Snowy Plover Recovery Unit 3. The goal of this
collaboration is to survey former salt ponds and other habitats for Western Snowy Plovers (Charadrius alexandrinus nivosus), determine nest success of Snowy Plover nests and contribute to the management of the San Francisco Bay’s population of breeding Snowy Plovers. In 2009, we recorded Snowy Plover numbers, site use, nest success, fledging success, use of habitat enhancement projects, nest predators and avian predator numbers throughout the Snowy Plover breeding season.

During the 2009 breeding season window survey of the Pacific coast (24 May– 7 June) we counted 147 adult Snowy Plovers in the Bay. In 2009, we determined the fate 163 Snowy Plover nests in the South San Francisco Bay (South Bay). Ninety-six of the nests hatched (59%), 51 were depredated (31%), six were abandoned (3.6%), four were flooded (2.5%), three had unknown fates (1.8%) and two were lost at hatch (1.2%).

On Refuge property, we determined the fate of seven nests in the Alviso salt pond complex (pond A8, the Alviso impoundment and the dry pan area of New Chicago Marsh), 33 nests in the Ravenswood complex (ponds RSF2 and R1 – R5) and 21 nests in the Warm Springs complex (ponds A22 and A23). Out of these nests, 42 hatched (68.8%), 17 were depredated (27.8%), 1 was abandoned (1.6%) and 1 had an unknown fate (1.6%).

This year we determined the fate of 97 Snowy Plover nests at Eden Landing Ecological Reserve. Of the 97 nests, 53 hatched (55%), 32 were depredated (33%), 2 were lost at hatching (2%), 4 were flooded (4%), 5 were abandoned (5%) and 1 had an unknown fate (1%).

We determined the fate of five nests at Hayward Shoreline, one nest in the Old Oliver Brothers North salt ponds, which was depredated, and four nests on EBRPD’s Least Tern island. Out of these four nests, one was depredated by a Killdeer (Charadrius vociferous), two nests were found with broken eggs and one hatched.

Throughout the South Bay, we banded 113 chicks this breeding season. From visual observations, we determined that 28 chicks survived to fledging (24.8%) as of 30 September 2009. Using only the data where all the chicks in the brood were banded (n=29), the number of chicks fledged per male was 0.62.

During avian predator surveys we counted California Gulls (Larus californicus) and unidentified gulls as the most numerous avian predators in all areas surveyed.

SFBBO and the Refuge began a Snowy Plover habitat enhancement study beginning the winter of 2008 at Eden Landing Ecological Reserve. Enhancements consisted of oyster shells spread by hand at densities of five to eight shells/m² over seven one ha plots. More Snowy Plovers nested in shell plots than in control plots, and nests in shell plots were more likely to hatch than all other nests not in shell plots. The highest nest density we recorded was six active nests in a one ha shell plot.

SFBBO, with the help of H.T. Harvey and Associates, deployed camera systems at Snowy Plover nests at Eden Landing. Camera systems were placed at 24 nests and recorded footage 24 hours a day. We recorded eight depredation events on film, including two separate events where California Gulls depredated a Snowy Plover nest and chicks. The camera systems also recorded Common Ravens (Corvus corax), Northern Harriers (Circus cyaneus) and Red-tailed Hawks (Buteo jamaicensis) depredating Snowy Plover nests.

The South Bay Salt Pond Restoration Project, which encompasses much of the South Bay, should continue to consider the habitat requirements of Western Snowy Plovers in the restoration planning process, including the need for large expanses of dry salt pond nesting substrate adjacent to foraging areas.

Pond Complex

Alviso

Eden Landing

Ravenswood

Content available here

Colonial Waterbird Nesting Summary for the South San Francisco Bay, 2008

Dave Halsing — Tue, 26 Apr 2022 18:49:24 +0000

Colonial Waterbird Nesting Summary for the South San Francisco Bay, 2008 Dave Halsing Tue, 04/26/2022 - 11:49

Document Category

Scientific Reports

Author(s)

Schacter, Carley R.

Date

2008-12

Summary

This report conveys the results of the 2008 nesting waterbird monitoring program, led by the San Francisco Bay Bird Observatory.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Colonial Waterbird Nesting Summary for San Francisco Bay, 2009

Dave Halsing — Tue, 26 Apr 2022 18:47:05 +0000

Colonial Waterbird Nesting Summary for San Francisco Bay, 2009 Dave Halsing Tue, 04/26/2022 - 11:47

Document Category

Scientific Reports

Author(s)

Schacter, Carley R.

Date

2009-11

Summary

This report conveys the results of the 2009 nesting waterbird monitoring program, led by the San Francisco Bay Bird Observatory.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Colonial Waterbird Nesting Summary for San Francisco Bay, 2010

Dave Halsing — Tue, 26 Apr 2022 18:42:14 +0000

Colonial Waterbird Nesting Summary for San Francisco Bay, 2010 Dave Halsing Tue, 04/26/2022 - 11:42

Document Category

Scientific Reports

Author(s)

Karine Tokatlian

Date

2010-12

Summary

This report conveys the results of the 2010 nesting waterbird monitoring program, led by the San Francisco Bay Bird Observatory.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Colonial Waterbird Nesting Summary for San Francisco Bay, 2011

Dave Halsing — Tue, 26 Apr 2022 18:39:36 +0000

Colonial Waterbird Nesting Summary for San Francisco Bay, 2011 Dave Halsing Tue, 04/26/2022 - 11:39

Document Category

Scientific Reports

Author(s)

Karine Tokatlian

Date

2011-12

Summary

This report conveys the results of the 2011 nesting waterbird monitoring program, led by the San Francisco Bay Bird Observatory.

Keywords

Pond Complex

Alviso

Eden Landing

Ravenswood

Determining the Effects of Habitat Enhancements on Predators for Western Snowy Plover

lorenzof — Fri, 31 May 2019 00:28:27 +0000

Determining the Effects of Habitat Enhancements on Predators for Western Snowy Plover

Determining the Effects of Habitat Enhancements on Predators for Western Snowy Plover (Title Slide)

lorenzof Thu, 05/30/2019 - 17:28

Presentation

Author(s)

Date

Thu, 02/03/2011 - 1:30pm

Impact of Salt Ponds Restoration on California Gull Displacement and Predation on Breeding Waterbirds

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

Impact of Salt Ponds Restoration on California Gull Displacement and Predation on Breeding Waterbirds admin Wed, 11/22/2017 - 16:21

Document Category

Scientific Reports

Author(s)

Date

2013-06-30

Summary

The California Gull (Larus californicus) population in the South San Francisco Bay has increased from fewer to 200 breeding Gulls in 1982, to a peak of 52,172 in 2012. Specific to this study there were 46,030 breeding Gulls in 2010 and 37,716 breeding Gulls in 2011.

Keywords

Western Snowy Plover Monitoring in the San Francisco Bay Annual Report 2012

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

Western Snowy Plover Monitoring in the San Francisco Bay Annual Report 2012 admin Wed, 11/22/2017 - 16:21

Document Category

Progress Reports

Author(s)

Christina Donehower

Karine Tokatlian

Date

2013-01-31

Summary

The Pacific Coast population of the Western Snowy Plover (Charadrius nivosus nivosus, Snowy Plover) breeds along or near tidal waters and is behaviorally distinct from the interior population (Funk 2007). Coastal-breeding Snowy Plovers have declined as a result of poor reproductive success, likely due to habitat loss, habitat alteration, human disturbance, and increasing predation pressure (Page et al. 1991, USFWS 2007). In response to this decline, the U.S. Fish and Wildlife Service listed the Pacific Coast Western Snowy Plover population as federally threatened in 1993 (USFWS 1993).

Keywords

birds

Western Snowy Plover Numbers, Nesting Success, Fledging Success and Avian Predator Surveys in the San Francisco Bay, 2011.

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

Western Snowy Plover Numbers, Nesting Success, Fledging Success and Avian Predator Surveys in the San Francisco Bay, 2011. admin Wed, 11/22/2017 - 16:21

Document Category

Scientific Reports

Author(s)

Cheryl M. Strong