Isle Lake
Grebe Survey Summary
- Max Adults: ~230
- Year: 2004, 2007
- Most Recent Adults: >=40
- Year: 2016
- Survey Type: Shore; Boat; Air
- Most Common Threats Reported: Lack of/poor nesting habitat; wind/wave inundation; water level too low; egg predation; human/development/boat disturbance; nest abandonment; nest parasitism; drought/lack of water
- Lake name:
- Isle Lake
- Location:
- Alberta
- Latitude:
- 53.6263889
- Longitude:
- -114.7280556
- Surface area (km2):
- 23
- Basin type:
- non-reservoir
- Primary vegetation for nesting:
- bulrush (Scirpus spp)
- Management agency:
- Alberta Environment; Alberta Parks
- Lake use:
- recreation
- Region associations:
- Sturgeon River watershed; North Saskatchewan River Basin; Lac Ste. Anne; Wabamun Lake; Isle Lake Natural Area
- Designations:
- Park; Natural Area
- Comments:
- A shallow large lake. Water levels have been declining since the 1990s.
Surveys (10)
Survey Citation:
COSEWIC. 2014. COSEWIC assessment and status report on the western grebe (Aechmophorus occidentalis) in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 55 pp. www.registrelep-sararegistry.gc.ca/default_e.cfm
-
Type
shore; boat; air -
Time period
1970, 2011 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 228 | 1991-2011 |
| Most Recent Adults | 1 to 100 | ? | 2011 |
| 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:
From Table A.2, maximum counts of breeding Western grebes from surveys mostly conducted during nesting season from June and July (sourced from Wilson, A. and Smith, P.A. 2013. Distribution and population status of Western Grebes in Canada. Unpublished report for the Canadian Wildlife Service). Stated as 20 year chunks: 1970 - 1990 and 1991 - 2011 without breaking those down into years or other details. Surveys every year from 2001 to 2010 (ASRD/ACA 2013) show large annual fluctuations and overall decline.
Survey Citation:
Hanus, S., H. Wollis, and L. Wilkinson. 2002. Western (Aechmophorus occidentalis) and Eared (Podiceps nigricollis) Grebes of Central Alberta: inventory, survey techniques and management concerns. Alberta Sustainable Resource Development, Fish and Wildlife Division, Species at Risk Report No. 41. Edmonton, Alberta, Canada.
-
Type
shore -
Time period
14 June 2001, 17 June 2001 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 154 | 2001 |
| Most Recent Adults | 101 to 500 | 154 | 2001 |
| Max Nests | 1 to 100 | 77 | 2001 |
| Most Recent Nests | 1 to 100 | 77 | 2001 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
One of three major Western grebe breeding lakes (Lac Ste. Anne, Wabamun Lake, and Isle Lake). Two colonies at this one, 91% of nests active. Population has been present beyond 20 years (Purdy et al. 1983).
Survey Citation:
Erickson, M. E. 2010. Persistence and abundance of the western grebe in Alberta. Dissertation. University of Alberta. Edmonton, Alberta, Canada. Same lakes and abundance estimated were checked against Erickson, M. E., C. Found-Jackson, and M. S. Boyce. 2017. Habitat associations with counts of declining western grebes in Alberta, Canada. Avian Conservation and Ecology. 12(1):12. Appendix to Erickson et al 2014 is unavailable but presumed to be the same list of lakes and abundance estimates.
-
Type
shore -
Time period
24 June 2009, 11 August 2009 -
Source
Dissertation -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 234 | 2007 |
| Most Recent Adults | 101 to 500 | 130 | 2009 |
| 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:
From Table B.1 and Table C.1, survey method and date for 2009 field season, latest abundance estimate from 2009, and maximum abundance estimate is from the 2007 field data. 24 June 2009 is from shoreline survey, 23 July and 11 August 2009 surveys are nest or brood counts (does not specify which).
Survey Citation:
Prescott, D. R. C., J. Unruh, S. Morris-Yasinski, and M. Wells. 2018. Distribution and abundance of the western grebe (Aechmophorus occidentalis) in Alberta: an update. Alberta Environment and Sustainable Resource Development, Fish and Wildlife Policy Branch, Alberta Species at Risk Report No. 160, Edmonton, AB. 23 pp.
-
Type
boat -
Time period
1930, 2016 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 228 | 2004 |
| Most Recent Adults | 1 to 100 | >=40 | 2016 |
| Max Nests | 1 to 100 | presence | 1930, 1971, 1982, 1983, 1989, 1990, 1993, 1998, 2001-2011 |
| Most Recent Nests | 0 | 0 | 2016 |
| Max Chicks | 1 to 100 | presence? | 1930, 1971, 1982, 1983, 1989, 1990, 1993, 1998, 2001-2011 |
| Most Recent Chicks | 0 | 0 | 2016 |
Comments:
Sources are eBird (accessed Nov 2015 and Dec 2016), AESRD and ACA (2013), FWMIS (Accessed Nov 2015 including field surveys from 2015 and 2016), Hanus et al. 2002a, Hanus et al. 2002b, Berg et al. 2004, Kemper et al. 2008, Wollis and Stratmoen 2010, Erickson 2010, Folinsbee, J. 1989, Hanus 2002, Purdy et al. 1983, and Purdy et al. 1983. This report is an update of Western grebe distribution in Alberta based on previous provincial status reports, additional breeding records (between May 1 to August 31) through end of 2014 from new sources. Lakes were visited in 2015 and 2016 for occupancy and habitat conditions. In a given year, if there are multiple sources of data, the highest count was given. From the Appendix, I entered only lakes (67) with evidence of breeding (either chicks or nests, but doesn't specify which and no nest nor chick numbers provided). Otherwise, 318 lakes supported adult grebe populations. This report compiled a list of 35 priority lakes for grebe surveys and management actions through the provincial recovery plan based on high population and habitat scores. New lakes with breeding reveal a changing system of lake occupancy and possibly higher populations than previously thought in Alberta.
Survey Citation:
Alberta Sustainable Resource Development and Alberta Conservation Association. 2006. Status of the western grebe (Aechmophorus occidentalis) in Alberta. Alberta Sustainable Resource Development, Wildlife Status Report No. 60, Edmonston, AB. 29 pp.
-
Time period
2004 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 228 | 2004 |
| Most Recent Adults | 101 to 500 | 228 | 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:
Data from Table 2 ("Summary of the most recently published western grebe population data for the province of Alberta") sourced from Berg et al. 2004. The only colony in the Stony Plain region that has doubled from 2003 to 2004 (Berg et al. 2004).
Survey Citation:
Alberta Sustainable Resource Development and Alberta Conservation Association. 2013. Status of the western grebe (Aechmophorus occidentalis) in Alberta: Update 2012. Alberta Sustainable Resource Development. Alberta Wildlife Status Report No. 60 (Update 2012). Edmonston, AB. 48 pp.
-
Type
boat -
Time period
2002, 2009 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 154 | 2002 |
| Most Recent Adults | 101 to 500 | 130 | 2009 |
| 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:
Data from Table 2 ("Most recent abundance estimates from known western grebe breeding lakes in Alberta based on structured surveys; at some lakes, more recent observations have been made but these were not complete counts"). Table 2 data is from Wollis and Stratmoen 2010. Estimates of western grebe numbers are a minimum estimate for that year derived from nest counts (x2 for breeding adult numbers) or boat surveys of adult grebes, using highest estimate. According to Table 4, the 2009 count is 1% of estimated proportion of provincial population. Water levels were low and there is much recreation and development (H. Wollis, pers. comm.). This lake has a high amount of recreational activity.
Survey Citation:
Wollis, H., and C. Stratmoen. 2010. Population study of western grebes in Alberta 2001-2009: Implications for management and status designation. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report No. 138. Edmonton, AB. 18 pp.
-
Time period
2007, 2009 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 154 | 2007 |
| Most Recent Adults | 101 to 500 | 130 | 2009 |
| 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:
This report is a continuation of a western grebe monitoring project started in 2001 to survey colonies in Alberta and assess population trends and distribution. Known and new colonies were searched for each year through 2009. This entry is from Table 1 and Table 2 comparing most recent estimate of # adults with highest estimate year.
Survey Citation:
Berg, G., L. Wilkinson, H. Wollis, and D. Prescott. 2004. Western (Aechmophorus occidentalis) and Eared (Podiceps nigricollis) grebes of central Alberta: 2004 field summary. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report No. 94. Edmonton, Alberta, Canada.
-
Type
boat -
Time period
2001, 2004 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 228 | 2004 |
| Most Recent Adults | 101 to 500 | 228 | 2004 |
| Max Nests | 101 to 500 | 114 | 2004 |
| Most Recent Nests | 101 to 500 | 114 | 2004 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Fourth year of monitoring population trends and reproductive success of western grebes in the Stony Plain, Alberta area and the first year for Parkland Region lakes. Ground nest surveys after "abandonment" were used to estimate total breeding adult populations. Boat surveys and/or shoreline surveys were conducted between June 16 and July 16, 2004 to monitor major colonies Hanus et al. (2002a, b) identified. Entered Table 1 with the addition of adult estimates by multiplying # of nests by 2. Isle Lake colony doubled from 2003, the only increase in this study.
Survey Citation:
Hanus, S., L. Wilkinson, and H. Wollis. 2002. Western (Aechmophorus occidentalis) and Eared (Podiceps nigricollis) grebes of Central Alberta: 2002 field season summary. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report Number 60. Edmonton, Alberta, Canada.
-
Type
shore -
Time period
10 June 2002, 3 July 2002 -
Source
Report -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | >124 | 2002 |
| Most Recent Adults | 101 to 500 | >124 | 2002 |
| Max Nests | 1 to 100 | 62 | 2002 |
| Most Recent Nests | 1 to 100 | 62 | 2002 |
| Max Chicks | N/A | N/A | N/A |
| Most Recent Chicks | N/A | N/A | N/A |
Comments:
Entered count numbers from total ground nest survey, otherwise the other survey dates were partial surveys. Fairly stable population from 2001 to 2002 but had a gradual colony decline in 2002. This lake was the only one in this study where the grebes nested around islands. Depredation and nest abandonment were the lowest and at the slowest rate out of the lakes that are part of this study. It is possible that the colony locations around islands helped distance them from potential predators but the tradeoff is that they may be more exposed to wind and wave action and human disturbance.
Survey Citation:
Environment and Climate Change Canada. 2021. Management Plan for the western grebe (Aechmophorus occidentalis) in Canada [Proposed]. Species at Risk Act Management Plan Series. Environment and Climate Change Canada, Ottawa. 5 iv + 52 pp.
-
Time period
2007, 2016 -
Source
Management plan -
Both Western and Clarks?
N
| Count Type | Range | Max | Year |
|---|---|---|---|
| Max Adults | 101 to 500 | 234 | 2007 |
| Most Recent Adults | 1 to 100 | >40 | 2016 |
| 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:
From Appendix B, data columns are historical high count, high count since 2000, and most recent count. Since minimum count was not stated, I entered the minimum from these columns though it might not be the actual minimum across the span of years reported. Also, there is no detail on years that were excluded from surveying so range of survey years may be inaccurate. Footnote for this lake indicates that for 2015 to 2016, breeding was confirmed, potential habitat was available, and lake was occupied by Western grebes. Sources are Prescott et al., 2018 and Alberta Environment and Parks, 2018.
Sources of Information
- Mitchell, P. 1990. Atlas of Alberta Lakes, University of Alberta Press. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/uidaho/detail.action?docID=3411706.; Hanus, S., L. Wilkinson, AND H. Wollis. 2002. Western (Aechmophorus occidentalis) and Eared (Podiceps nigricollis) Grebes of Central Alberta: 2002 Field Season Summary. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report Number 60. Edmonton, Alberta, Canada.
- Hanus, S., L. Wilkinson, AND H. Wollis. 2002. Western (Aechmophorus occidentalis) and Eared (Podiceps nigricollis) Grebes of Central Alberta: 2002 Field Season Summary. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report Number 60. Edmonton, Alberta, Canada.
- Isle Lake and Lac Ste Ann State of the Watershed Report 2017
- Isle Lake Natural Area
- Canadian Geographical Names Database (CGNDB)