Cascade Reservoir/Lake Cascade
Grebe Survey Summary
- Max Adults: 4982
- Year: 2018
- Most Recent Adults: 3182
- Year: 2023
- Survey Type: Shore; Boat; Air; Drone
- Most Common Threats Reported: Water level too low; water level too high; lack of/poor nesting habitat; wind/wave inundation; adult predation; water quality/contaminants/oil spills; human/development/boat disturbance; lack of fish food; drought/lack of precipitation/water; invasive species
- Lake name:
- Cascade Reservoir/Lake Cascade
- Location:
- Idaho
- HydroLAKE ID:
- 8978
- GRanD ID:
- 370
- Latitude:
- 44.523064
- Longitude:
- -116.053057
- Surface area (km2):
- 94.8
- Basin type:
- reservoir
- Dam completion date:
- 1947
- Management agency:
- Bureau of Reclamation; Idaho Department of Fish and Game (IDFG)
- Lake use:
- irrigation
- Region associations:
- North Fork Payette watershed; Boise River basin; Payette River basin; Lake Cascade State Park
- Designations:
- State Park; Wildlife Management Area
- Comments:
- Lake Cascade is a large reservoir of the Boise River and Payette River basins. It is popular for recreation and trophy fishing. It supports the largest population of breeding western and Clark's grebes in Idaho and estimated to represent 3% of the total population of western grebes. Water quality has been challenged by phosphorous loading and Harmful Algal Blooms. This reservoir is characterized by shallow water and water drawdown over the summer lowers levels even further, especially during drought years. The Bureau of Reclamation announced a pilot study in 2021 for optimal water management under conditions such as drought, water use, climate change, and other factors that limit water availability.
Surveys (13)
Survey Citation:
Trost, C. H., A. Gerstell. 1994. Status and distribution of colonial nesting waterbirds in southern Idaho, 1993. 110.
-
Type
shore -
Time period
5 July 1984 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 400 | 1984 |
| Most Recent Adults | 101 to 500 | 400 | 1984 |
| Max Nests | 101 to 500 | 200 | 1984 |
| Most Recent Nests | 101 to 500 | 200 | 1984 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Source is M. Collie who observed "hundreds in 1983".
Survey Citation:
I only have the species accounts. Idaho Department of Fish and Game. 2005. Idaho comprehensive wildlife conservation strategy. Boise (ID): Idaho Department of Fish and Game
-
Time period
N/A -
Source
Profile -
Both Western and Clarks?
N/A
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | N/A | N/A | N/A |
| Most Recent Adults | N/A | N/A | N/A |
| Max Nests | N/A | N/A | N/A |
| Most Recent Nests | N/A | N/A | N/A |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
D. Evans Mack personal communication cited for the threat of increased shoreline development and recreational boating though some nesting sites within WMAs.
Survey Citation:
Kimball, S. A. 2009. Behavioral Interactions of Breeding Bald Eagles (Haliaeetus Luecocephalus) at Lake Cascade, Idaho. 69.
-
Time period
N/A -
Source
Thesis -
Both Western and Clarks?
N/A
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | N/A | N/A | N/A |
| Most Recent Adults | N/A | N/A | N/A |
| Max Nests | N/A | N/A | N/A |
| Most Recent Nests | N/A | N/A | N/A |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Eagle nest climbs in 2000 resulted in subjective observations that Western grebes and Northern pikeminnows accounted for most of prey items. There's been an increase in eagle populations on the reservoir since 1990.
Survey Citation:
Idaho Department of Fish and Game. 2017. Idaho State Wildlife Action Plan, 2015. Boise (ID): Idaho Department of Fish and Game. Grant No.: F14AF01068 Amendment #1. Available from: http://fishandgame.idaho.gov/. Sponsored by the US Fish and Wildlife Service, Wildlife and Sport Fish Restoration Program.
-
Time period
N/A -
Source
SWAP -
Both Western and Clarks?
N/A
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | N/A | N/A | N/A |
| Most Recent Adults | N/A | N/A | N/A |
| Max Nests | N/A | N/A | N/A |
| Most Recent Nests | N/A | N/A | N/A |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Part of Idaho Batholith. Largest colony of Western and Clark's in the state. Up to 700 nests some years (doesn't say which). This entry for threats.
Survey Citation:
Cavitt, J. F., S. L. Jones, N. M. Wilson, J. S Dieni, T. S. Zimmerman, R. H. Doster, and W. H. Howe. 2014. Atlas of breeding colonial waterbirds in the interior western United States. Research Report, U.S. Department of the Interior, Fish and Wildlife Service, Denver, Colorado.
-
Type
boat -
Time period
25 June 2010 -
Source
Summary -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 4700 | 2010 |
| Most Recent Adults | >1000 | 4700 | 2010 |
| Max Nests | N/A | N/A | N/A |
| Most Recent Nests | N/A | N/A | N/A |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Evans-Mack is observer, colony at Poison Creek. Direct count of individuals to estimate # of breeding birds. Conducted as part of Western Colonial Waterbird Survey (WCWS), a breeding survey of 18 species from May to July 2009 to 2011, resulting in this Atlas.
Survey Citation:
Historical data in Cavitt, J. F., S. L. Jones, N. M. Wilson, J. S Dieni, T. S. Zimmerman, R. H. Doster, and W. H. Howe. 2014. Atlas of breeding colonial waterbirds in the interior western United States. Research Report, U.S. Department of the Interior, Fish and Wildlife Service, Denver, Colorado.
-
Type
shore -
Time period
7 July 1994 -
Source
Summary -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 1217 | 1994 |
| Most Recent Adults | >1000 | 1217 | 1994 |
| Max Nests | 101 to 500 | 400 | 1994 |
| Most Recent Nests | 101 to 500 | 400 | 1994 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Gold Fork. Trost was observer but this was not in Trost paper. Estimate, not direct count, of breeding birds.
Survey Citation:
Evans Mack, D., and B. Wagner. 2022. Aechmophorus Grebe (Western and Clark’s) Monitoring on Cascade Reservoir, Idaho,
2003–2021. Idaho Department of Fish and Game. McCall, Idaho.
-
Type
shore; boat; drone -
Time period
June 2003, 2 August 2021 -
Source
Report -
Both Western and Clarks?
Y
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 4982 | 2018 |
| Most Recent Adults | >1000 | 4215 | 2021 |
| Max Nests | >1000 | >3000 | 2020 |
| Most Recent Nests | >1000 | >3000 | 2020 |
| Max Chicks | >1000 | 1443 | 2007 |
| Most Recent Chicks | 0 | 0 | 2021, 2022(?) |
Comments:
Cascade Reservoir supports the largest Western and Clark's grebe breeding population in the state. Water is very shallow around the perimeter. For the last 8 years of annual adult surveys, the average number of adults is approximately 3000. Includes University of Idaho Grebe Research Project data and some personal communication on 2022 (zero chicks counted by Betsy Wagner though our technicians may have seen some). Only have # nest count data from 2003, 2004, 2017 to 2019 at this time. 2020, 2021, and 2022 nest count data is pending.
Survey Citation:
Ivey, G.L., and C.P. Herziger. 2006. Intermountain west waterbird conservation plan, version 1.2. A plan associated with the Waterbird Conservation for the Americas Initiative. Published by U.S. Fish and Wildlife Service Pacific Region, Portland, Oregon.
-
Time period
2004 -
Source
Conservation Plan -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 2700 | 2004 |
| Most Recent Adults | >1000 | 2700 | 2004 |
| Max Nests | >1000 | 1350 | 2004 |
| Most Recent Nests | >1000 | 1350 | 2004 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Appendix D, Table D-3, is 1350 nests and 2700 area population estimate (nests x 2) for Cascade Reservoir 2004. Population data source is C. Moulton personal communication. No other info provided. Referenced in G. Ivey's ID Waterbird Atlas spreadsheet for his work with Region 1 - Non Game but date of 1 January 2004 is incorrect month and date. I don't know what is correct date.
Survey Citation:
Ivey, G.L., and C.P. Herziger. 2006. Intermountain west waterbird conservation plan, version 1.2. A plan associated with the Waterbird Conservation for the Americas Initiative. Published by U.S. Fish and Wildlife Service Pacific Region, Portland, Oregon.
-
Time period
N/A -
Source
Conservation Plan -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 200 | 1990s-2004 |
| Most Recent Adults | 101 to 500 | 200 | 1990s-2004 |
| Max Nests | N/A | N/A | N/A |
| Most Recent Nests | N/A | N/A | N/A |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Appendix D, Table D-3, is "Other N. ID sites": 200 breeding population. Population data source is C. Moulton/Taylor personal communication. No other info provided.
Survey Citation:
Manning, A. 2006. Colony list, unpublished data.
-
Time period
2003 -
Source
Summary -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 1 to 100 | presence | 2003 |
| Most Recent Adults | 1 to 100 | presence | 2003 |
| Max Nests | 1 to 100 | presence | 2003 |
| Most Recent Nests | 1 to 100 | presence | 2003 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Unpublished data from Ann Manning with the Utah Division of Wildlife, forwarded by Gary Ivey. Ivey said year saved was 2006 but otherwise unknown when this list was determined by Manning, hence year noted as 2006 or prior. Western grebe colony survey done in 2003. No other info provided.
Survey Citation:
Trost. C.H. 1994. Status and distribution of colonial nesting waterbirds in northern Idaho and selected species in southern Idaho. 31 pp.
-
Type
shore; boat; air -
Time period
7 July 1994 -
Source
Report -
Both Western and Clarks?
Y
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 1217 | 1994 |
| Most Recent Adults | >1000 | 1217 | 1994 |
| Max Nests | 101 to 500 | 500 | 1994 |
| Most Recent Nests | 101 to 500 | 500 | 1994 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Source is this study. Largest grebe colony in ID. Grebes along the western shore where it is hard to count. Many with chicks but doesn't state #. In shallow lakes that are vulnerable to fish kills, grebe populations may fluctuate. However, breeding lakes that are eutrophic, like Cascade Reservoir, may support small fish populations.
Survey Citation:
IDFG adult and brood surveys for 2021 and 2022 and University of Idaho data, pending, 2021.
-
Type
shore; boat; drone -
Time period
14 June 2021, 4 August 2022 -
Source
Datasheets, pers comm -
Both Western and Clarks?
Y
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 4215 | 2021 |
| Most Recent Adults | >1000 | 3742 | 2022 |
| Max Nests | 101 to 500 | ~150 | 2021 |
| Most Recent Nests | 0 | 0? | 2022 |
| Max Chicks | 0 | 0 | 2021, 2022 |
| Most Recent Chicks | 0 | 0 | 2021, 2022 |
Comments:
Data is from Betsy Wagner, Senior Wildlife Technician, and Jennifer Struthers, Regional Wildlife Diversity Biologist, emails for IDFG pre-nesting and post-nesting/brood annual surveys from 2021 and 2022 respectively. The nest numbers for 2021 is pending University of Idaho grebe research results. IDFG did not detect nesting in 2022. There is possibility of nest building in 2022 but that was not confirmed. Both 2021 and 2022 had very low water levels and potential nesting habitat was not accessible to grebes for much of the nesting season.
Survey Citation:
IDFG adult and brood surveys for 2023. Wagner, B. Senior Wildlife Technician, IDFG, personal communication.
-
Type
shore; boat; drone -
Time period
June 2023, July 2023 -
Source
Personal communication -
Both Western and Clarks?
Y
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | >1000 | 3182 | 2023 |
| Most Recent Adults | >1000 | 3182 | 2023 |
| Max Nests | pending | pending | 2023 |
| Most Recent Nests | pending | pending | 2023 |
| Max Chicks | 101 to 500 | 334 | 2023 |
| Most Recent Chicks | 101 to 500 | 334 | 2023 |
Comments:
Data is from Betsy Wagner, Senior Wildlife Technician, and Jennifer Struthers, Regional Wildlife Diversity Biologist, emails for IDFG pre-nesting and post-nesting/brood annual surveys from 2023. Nest numbers are pending from Owyhee Air and IDFG operated drone orthomosaics. Most broods were 1 - 2 chicks but there were >10 broods with 3 chicks and one brood with 4 chicks!
Sources of Information
- Messager, M. L., B. Lehner, G. Grill, I. Nedeva, and O. Schmitt. 2016. Estimating the volume and age of water stored in global lakes using a geo-statistical approach. Nature Communications 7:13603. Data is available at www.hydrosheds.org.; Lehner, B., C. Reidy Liermann, C. Revenga, C. Vorosmarty, B. Fekete, P. Crouzet, P. Doll, M. Endejan, K. Frenken, J. Magome, C. Nilsson, J.C. Robertson, R. Rodel, N. Sindorf, and D. Wisser. 2011. Global Reservoir and Dam Database, Version 1 (GRanDv1): Dams, Revision 01. Palisades, New York: NASA Socioeconomic Data and Applications Center (SEDAC).
- Lehner, B., C. Reidy Liermann, C. Revenga, C. Vorosmarty, B. Fekete, P. Crouzet, P. Doll, M. Endejan, K. Frenken, J. Magome, C. Nilsson, J.C. Robertson, R. Rodel, N. Sindorf, and D. Wisser. 2011. Global Reservoir and Dam Database, Version 1 (GRanDv1): Dams, Revision 01. Palisades, New York: NASA Socioeconomic Data and Applications Center (SEDAC).
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