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Southern Flying Squirrel (Glaucomys Volans)

Population Sizes and Trends: Great Lakes Population

Search Effort

Very little systematic trapping for southern flying squirrels has occurred in the Great Lakes Plains Population. Population data are available for Point Pelee National Park (Bednarczuk and Stephens 2004; Bednarczuk 2003; Adams 1997) and Algonquin Provincial Park (G. Holloway unpubl. data). From 2002 through 2004, J. Bowman, P.J. Wilson, G.L. Holloway and J.R. Malcolm (unpubl. data.) completed 42 971 trap nights at 26 different sites throughout south and central Ontario (see Table 5) capturing 500 southern flying squirrel individuals 748 times. Their annual catch per unit effort was 1.36 captures per 100 trap nights in 2002 (8 542 trap nights), 3.57 captures per 100 trap nights in 2003 (16 597 trap nights), and 0.22 captures per 100 trap nights in 2004 (17 832 trap nights). Catch per unit effort data derived from other locations in Ontario are reported in Table 6.

Table 5: Site Locations of Southern Flying Squirrel Trapping Effort in Ontario, 2002–2004
G. volans
Trap NightsG. volans
Trap NightsG. volans
Trap Nights
Clear Creek Forest  yes1 500yes120 
Krug Forest (FON Tract)  no128  No
Sites in Grey County  no<50   
Sites in Bruce County  no130   
Ganaraska Forest  no266yes400Yes
Henderson Line Woodlot (Peterborough)    yes75Yes
Keene Road Woodlot (Peterborough)    no75No
Mark S. Burnham Provincial Park    no75No
Oliver Property (Trent Research Station, Pigeon Lake)yes68yes87yes84 
Kawartha Highlands Signature Siteyes183yes120yes60Yes
Leslie M. Frost Centreyes154yes440yes400Yes
Crown land adjacent to Killbear Provincial Park  yes30  Yes
Haliburton Forest & Wildlife Reserve    yes2 685yes
Crown land adjacent to Killbear Provincial Park  yes30  yes
Algonquin Provincial Park - Hwy 60yes5 043yes9 499no11 295yes
Algonquin Provincial Park - Achrayyes3 094yes2 286no900yes
Algonquin Provincial Park - Kiosk  yes930no128yes
Killarney Provincial Park  yes367no180yes
Nipissing Crown Game Preserve  no140   
North of Mattawa (Olrig and Antoine Townships)  yes315no400yes
Emerald Lake (Afton Township)  yes345  yes
Highway 11 corridor between Temagami North and Latchford    no420 

Source for all data: J. Bowman, P.J. Wilson, G.L. Holloway and J.R. Malcolm (unpubl. data.), except Clear Creek Forest: Pasma and Dobbyn (2003).


Table 6: Live-trapping Data from Various Southern Flying Squirrel Field Projects in Ontario, 1993 to 2003 (* denotes catch per unit effort corrected for closed but empty traps or non-target species)
Catch per
Unit Effort
Point Pelee National Park200115544%*Bednarczuk 2003
20036822%*Bednarzcuk and Stephens 2004
Clear Creek Forest2003386.0%*Pasma and Dobbyn 2003
Norfolk Township1993/941140.84%Adams 1995
200039645.8%Bednarczuk 2003
Hamilton1999 – 2001200+20-50%Bednarczuk and Judge 2002
Minden20012121.6%Bednarczuk 2003
Trent University Research Station2001255%L. Bridges pers. comm. 2004
200246%P. Wilson pers. comm. 2004
OMNR provincial study (Table 5)20028 542 TN*1.36%Bowman et al. unpubl. data
200316 597 TN*3.57%
200417 832 TN*0.22%

* denotes number of Trap Nights


There is no abundance estimate for the Great Lakes Plains Population. Multiplying even a conservative density estimate by the area of Extent of Occurrence would provide a vast over-estimate of population size because the Area of Occupancy (unknown) is a small fraction of the Extent of Occurrence.

Estimates of population size for southern flying squirrels are constrained by low capture rates and unequal capture of individuals. G. volans also exhibits wide annual variation, rendering any point-in-time estimate unreliable. Published densities vary widely (Table 7). Raised trap height can increase trapping success (Risch and Brady 1996), but catch per unit effort is usually quite low (Table 6).

The total number of individuals of all ages in the Great Lakes Plains population may number in the several thousands to tens of thousands, the majority of which are mature individuals capable of reproducing. Roughly half of the marked population at Point Pelee National Park was composed of mature individuals in 2001, and 75% of captured individuals in 2003 were mature (Bednarczuk and Stephens, 2004). During trapping in Hamilton in 2001, 2.5 times more adults than juveniles were captured (Bednarczuk and Judge 2002).


Table 7: Southern Flying Squirrel Density Estimates
LocationDensity (per ha)Forest typeSource
Point Pelee National Park, Ontario1.7 – 2.3 (2001)
hackberry, maple, oakBednarczuk and Stephens, 2004
0.3 – 0.4 (2003)
Algonquin Prov. Park, Ontario2.9 (2003)beech – mapleG. Holloway unpubl. data
2.6 (2003)sugar maple
0.6 (2003)mixed maple - conifer
no captures in 2004 
Nova Scotia0.9 – 8.4*mixedwoodLavers 2004
Michigan2.82oak – hickoryJordan 1948
5 Baker 1983 (in Stabb 1988)
Maryland6.2hardwood - coniferGilmore and Gates 1985
Virginia34.0 – 38.0hardwood – pineSawyer and Rose 1985
3.7 – 13.8oak – hickory - beechSonenshine et al. 1979
Arkansas0.2 – 0.9pine – hardwoodTaulman 1999
Alabama1.8 – 3.5pine – oakHatten 1992

* Lavers (pers comm 2004) advised caution when using these population data as they are based on few captures.

Fluctuations and Trends

There are few data on population fluctuations for the Great Lakes Plains population, due to a lack of long-term monitoring studies and no historical data. However, results from northern and central Ontario and Point Pelee National Park suggest that southern flying squirrels undergo wide population fluctuations throughout the Great Lakes range.

Given widespread habitat loss throughout southern Ontario (see Habitat Trends: Great Lakes), a decline from historical levels has probably occurred. Observed range extensions in central Ontario appear subject to fluctuation and may not offset declines in the southern part of G. volans’ Great Lakes Plains population range.

Rescue Effect

There is limited possible rescue effect for the Great Lakes Plains population. Immigration to Ontario is restricted by the Great Lakes and their associated rivers. Flying squirrels are poor swimmers because the patagium restricts leg movement. They therefore can cross water bodies no wider than “one glide”; maximum 50 m.

The only land border between the United States and Canada is in southwestern Québec. There is little known about southern flying squirrel distribution in this area of Québec or adjacent states New York, Vermont and New Hampshire.