Sacramento National Wildlife Refuge
Grebe Survey Summary
- Max Adults: 9 (1976), presence (other years)
- Year: 1976, early 1980s, early 1990s
- Most Recent Adults: presence
- Year: early 1990s
- Survey Type: N/A
- Most Common Threats Reported: Water level fluctuation (too high and low); wind/wave inundation
- Lake name:
- Sacramento National Wildlife Refuge
- Location:
- California
- Latitude:
- 39.416691
- Longitude:
- -122.161432
- Primary emergent vegetation:
- Tule (Typhus sp. and Sciurpus sp.)
- Primary vegetation for nesting:
- Tule (Typhus sp. and Sciurpus sp.)
- Management agency:
- U.S. Fish and Wildlife Service
- Lake use:
- recreation
- Region associations:
- Central Vally; Sacramento NWR
- Designations:
- National Wildlife Refuge
- Comments:
- No specific location provided at this refuge. Coordinates are for Pool 2, the largest waterbody in the refuge. This refuge is part of a complex of refuges in the Central Valley and the last known remnant of a large Central Valley grebe population. A few grebes attempt to nest here every year. The lake was drained and refilled in March 1976. The lake was drained and refilled in March 1976. Sacramento NWR and region was experiencing multi-year drought conditions.
Surveys (2)
Survey Citation:
Feerer, J. L. and R. L. Garrett. 1977. Potential Western Grebe extiinction on California lakes. Cal-Neva Wildlife Transactions. 13(1):80-89.
-
Time period
1976 -
Source
Journal Article -
Both Western and Clarks?
Y
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 1 to 100 | 9 | 1976 |
| Most Recent Adults | 1 to 100 | 7 | 1976 |
| Max Nests | 1 to 100 | 3 | 1976 |
| Most Recent Nests | 1 to 100 | 3 | 1976 |
| Max Chicks | 0 | 0 | 1976 |
| Most Recent Chicks | 0 | 0 | 1976 |
Comments:
This report presents survey data from spring 1976 of Clear Lake, Eagle Lake, Salton Sea NWR, Topaz Lake, Sacramento NWR, Lake Earl, and Tule Lake (Klamath Basin NWR) and compares to historical data with focus on Clear Lake issues. No info on how surveys were conducted. This refuge is part of a complex of refuges in the Central Valley and the last known remnant of a large Central Valley grebe population. A few grebes attempt to nest here every year. The lake was drained and refilled in March 1976. In May 1976, 9 adult grebes were counted with some exhibiting courtship behavior. In August 1976, 7 adults and and 3 nests were observed. However, the pond was flooded and the nests were submerged (J. Hammernick, pers. comm.). There is no historical breeding references. From Table 1, colony is protected, recreation is the main use of lake, there is no shoreline development, spring water level stability is unstable.
Survey Citation:
Ivey, G. L. 2004. Conservation assessment and management plan for breeding Western and Clarkâs Grebes in California. Unpublished technical report. American Trader Trustee Council, California. . Accessed 15 January 2020.
-
Time period
early 1980s, early 1990s -
Source
Conservation Assessment, Management Plan -
Both Western and Clarks?
Y
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 1 to 100 | presence | early 1980s, early 1990s |
| Most Recent Adults | 1 to 100 | presence | early 1990s |
| Max Nests | 1 to 100 | presence | early 1980s, early 1990s |
| Most Recent Nests | 1 to 100 | presence | early 1990s |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
This entry to capture historical record of breeding grebes in CA prior to 2002. There were breeding grebes and noted as colony site in "recent years" (Garrett and Dunn 1981, Small 1994). No years provided so estimating early 1980s and early 1990s due to source years of 1981 and 1994.