Wild Game Aerial Survey Wildlife Management

Transcription

1 Wildlife Management Bighorn Sheep Survey of Designated Winter Ranges within Alberta Wildlife Management Units Data Summary Report Prepared by: Jeff Kneteman, Environment and Parks, Operations Division, Upper Athabasca Region, Hinton May 2016 Page 1 of 26

2 Acknowledgements The survey was conducted by pilot S. Wooten, navigator/observers J. Kneteman and M. Russell and observer/recorders B. Box, L. Dewart, C. Charbonneau, D. Hobson, J. Lockhart and L. Vander Vennen. Abstract During the 2016 survey of native winter range in WMUs 437, 438, 439, 440, 442, 444, 445, 446, and mine disturbed lands in WMU 446, 1696 bighorn sheep were observed, and 1639 bighorns classified. Composition was 437 rams (27%), 870 ewes (53%) and 332 lambs (20%; Table1). Adults were composed of 33% rams and 67% ewes over all WMUs surveyed, but adult sex ratio was 44% rams and 31% rams south and north of the Athabasca River respectively. Overall, adult sex composition and lambs as a proportion of total sheep are consistent with good reproductive and recruitment potential, but the high male proportion south of the Athabasca River suggests a female skewed distribution to lands not covered in the aerial survey. Introduction Aerial surveys of the Eastern Slopes of Alberta for bighorn sheep (Ovis canadensis) abundance, composition and location have been conducted since Since 1978, surveys have focused on selected winter ranges, where concentrations of bighorn sheep had been identified during previous flights. This report summarizes observations of bighorn sheep obtained during an aerial survey of selected winter ranges on January 30, 31 and February 1, 2, 7, 8, 9, 10, 11, The objective of the survey was to document the abundance and composition of bighorn sheep in Cadomin and Willmore census zones. A ground survey of the adjacent Luscar & Gregg River Coal Mine census zone was conducted by mine operators. Methods Fifteen of the selected winter ranges in WMUs were surveyed in 2016 (Table 1). A Bell 206 helicopter was used to survey each mountain complex and associated drainages for bighorn sheep and other ungulates. Each selected winter range was flown at an altitude of m ( feet) above sea level, in an attempt to provide complete coverage of each complex. The flight crew consisted of the pilot, navigator/observer, an observer, and a recorder/observer. The navigator was responsible for classifying each group of ungulates observed, while the observer provided a total count. The recorder/observer recorded all data and provided supplemental observations. The location of each animal or group of animals was identified using a Geographical Positional System (GPS). Sheep were classified according to sex (ewes or rams) and age (lambs or adults). All sheep one year or older were considered adult. Rams were further classified according to horn-size categories: ¼ curl, ½ curl, ¾ curl, or 4/5 curl (legal). Unclassified sheep were either rams (horn size could not be determined) or could not be identified based on either sex or age. Other ungulates observed were also classified, if possible, according to sex and age. Page 2 of 26

3 Total sheep numbers and herd composition were compared to the results from previous surveys ( ) of the study area. The locations of sheep sightings from the 2016 survey were plotted on GIS (Map info and Google) maps, based on winter range designations. Observations of other ungulate species were totaled and summarized. Results and Discussion During the 2016 survey of native winter range in WMUs , 442, and and mine disturbed lands in WMU 446, 1696 bighorn sheep were observed and 1639 bighorns classified. Composition was 437 rams (27%), 870 ewes (53%) and 332 lambs (20%; Table 1). Adults were composed of 33% rams and 66% ewes. Composition, as measured by adult sex composition and lambs as a proportion of total sheep, indicates good reproductive and recruitment potential. However approaching sex parity (44% males) south of the Athabasca suggests a female skewed distribution to sheep ranges not included in the aerial surveys, consistent with trending since the early to mid- 1990s. The strong female skew (31% males) in adult sex ratio north of the Athabasca River is consistent with historical findings. Bighorn abundance continues to decline on native range in WMU 438, now approaching <50% of observed bighorn presence during the period of However, productivity of native range remains high, typically exceeding 50 lambs/100 ewes and rarely declining below 40 lambs:100 ewes in late winter. Emigration to novel range on coal mines is consistent with the decline in bighorn abundance on native range. Declining abundance and historical low productivity of bighorns on coal mines increase concerns that a sink effect is overwhelming native range productivity and the ability to support bighorn abundance on the larger landscape. Bighorn sheep abundance in WMU 440 was the highest ever observed consisting of 449 animals which included 244 ewes and 0.44 lambs/ewe. Sheep abundance was among the highest observed since 1972 in WMU 442 and productivity was adequate (19% of all sheep were lambs). With the exception of the Swift-Horn Creek winter range in WMU 442, observed sheep abundance North of the Smoky River was lower than in previous years. Strong winds impeded surveys and presumably reduced observations of sheep relative to earlier surveys. Sheep productivity was typically low on the coal mine dominated ranges of WMU 446 with lambs comprising only 14% of 154 classified bighorn sheep. Legal ram presence in late winter remained high in WMUs 437 and 438 south of the Athabasca River at 12% of all classified sheep (n= 328). However legal ram presence remained low at 2.5% of 1311 classified sheep north of the Athabasca River. In contrast 10% of all classified sheep observed (n=490) in the upper Athabasca Drainage of Jasper National Park in late winter 2016 were legal rams. Page 3 of 26

4 Table 1. Abundance and age/sex classification of bighorn sheep by winter range on Alberta provincial lands; January - March 2016 WMU Winter Range Total Sheep Classified 1/4 curl 1/2 curl 3/4 curl Legal U/C Rams Total Rams 436 Ruby-Thistle n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a 437 Redcap Whitehorse Folding Mountain WMU 438 Total *Brule-Solomon Total 440 Hayden Ridge Rocky Pass North Berland Moon &Planet Mumm &Collie Total Monaghan Triangle Swift Horn Total Stearn Torrens SRC -Caw Grand Total *Brule-Solomon includes all sheep observed on the historical JNP Brule survey complex and the historical provincial Solomon survey complex Page 4 of 26

5 Table 2. Winter ranges not previously surveyed that were examined in for potential to include in the regular survey program. Results not included in the WMU results or Grand Totals displayed in Table. 5. WMU Winter Survey Total Classified Range Sheep Base 1/4 1/2 3/4 legal U/C 440 N. Persimmon Deneor Ruby-Thistle Page 5 of 26

6 Table 3. Sheep Management Areas (SMA), wildlife management units (WMU) and sheep winter ranges surveyed in the Foothills area *denotes surveyed, x not surveyed SMA WMU Complex Name Year Surveyed* 1994/ SRC/Caw Ridge x * * x x * x * Mount Torrens * x x x * x x x x x x x * * Mount Stearn * x x x x * x * * x x * x * Swift & Horn * x x x * * * x * x x * x * Creeks The Triangle * x x x * * * x * x x * x * Monoghan * x x x * * * * * x x * x * Range Hayden Ridge * * x x * * * x * x x * x * Rocky Pass * * x x * * * x * x x * x * North Berland * * x x * * * x * x x * x * North x x x x x x x x * x x x x x Persimmon Deneor x x x x x x x x * x x * x x Moon & Planet * * x x * * * x * x x * x * Creeks Mumm & Collie * * x x * * * x * x * x * Creeks Solomon Creek * * x x * * * x * * * x * * Folding * * x x * * * * * * * x * * Mountain Whitehorse * * x x * * * * * * * * * * Creek Red Cap Range * * * * * * * * * x * * * * Ruby-Thistle x x x x x x x x * * * * * x Page 6 of 26

7 Table 4. Comparison of observed counts of bighorn sheep in WMUs from sampling periods between 1972 and 2016 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 446 SRC/Caw Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 445 Mount Torrens / * Not Surveyed 2008 Not Surveyed Dec ** *1999 totals were an underestimate, as weather did not allow for surveying part of the Dinosaur/Torrens Ridge complex. **includes three groups observed in the BC portion of a complex that is primarily in Alberta Page 7 of 26

8 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 444 Mount Stearn / Not Surveyed Incomplete Page 8 of 26

9 WMU Winter Range Survey Year Total Sheep Classified Base 1/4 1/2 3/4 legal U/C 442 Swift & Horn / Triangle / Page 9 of 26

10 Winter Survey Total Classified WMU Range Year Sheep Base 1/4 1/2 3/4 legal 442 Monaghan Range / Total / * Page 10 of 26

11 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 440 Hayden / Rocky Pass / Page 11 of 26

12 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 440 North Berland Moon & / Planet / Page 12 of 26

13 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal 440 Mumm & Collie / Total / Page 13 of 26

14 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 439 Solomon / ** ** ** ** Brule Solomon based on historic JNP survey unit Page 14 of 26

15 Survey Year Total Sheep Classified Base 1/4 1/2 3/4 legal U/C WMU Winter Range WMU 438 Folding Mountain / Whitehorse Creek Page 15 of 26

16 WMU 438 Winter Range Whitehorse Creek / Survey Year Total Sheep Classified Base 1/4 1/2 3/4 legal U/C TOTAL / Page 16 of 26

17 * Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 437 Redcap / Page 17 of 26

18 Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C 436 Ruby-Thistle Survey Total Classified WMU Winter Range Year Sheep Base 1/4 1/2 3/4 legal U/C Grand Total 1972** o ** native range / * * * *** * Page 18 of 26

19 2012* * * * * * Limited area surveyed see table 3. **1972 and 1975 surveys were restructured to correspond to winter range designations. ***1999 results are not directly comparable due to Mount Stearn not being surveyed Table 5. Selected population parameters late winter Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal WMU % lambs:100 Census Zone Year % rams % ewes lambs ewes % rams- % ewes % legal WMU / Dec Page 19 of 26

20 Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal WMU / Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal WMU Page 20 of 26

21 / : Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal WMU Oct / Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal WMU Page 21 of 26

22 / Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal WMU / Page 22 of 26

23 lambs:100 ewes % rams- % ewes Census Zone Year % rams % ewes % lambs WMU % legal / Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % legal Page 23 of 26

24 WMU Census Zone Year % rams % ewes % lambs lambs:100 ewes % rams- % ewes % full curl Luscar & Gregg River Mine Winter * Page 24 of 26

25 Appendix I. Late winter presence and composition of bighorn sheep on the Luscar and Gregg River Mines Census Zone (WMU 438). Data provided by Teck Coal Ltd. and Gregg River Mines Ltd., through Bighorn Wildlife Technologies Year Yearling 1/4 curl 1/2 curl 3/4 curl Full curl U/C Ewes Lambs Total * ** Class I Class II Class III ClassIV * Luscar Mine only ** April Page 25 of 26

26 Yearlings added to ¼ curl for comparative or analytical purposes Page 26 of 26