2001 Burrowing Owl Trend Block Survey and Monitoring, Brooks and Hanna Areas Alberta Species at Risk Report No. 51 Digitized by the Internet Archive in 2016 https://archive.org/details/2001burrowingowl00scob_0 2001 Burrowing Owl Trend Block Survey and Monitoring, Brooks and Hanna Areas D. Scobie Alberta Species at Risk Report No. 51 March 2002 /dlberfa SUSTAINABLE RESOURCE DEVELOPMENT Publication No.: ISBN: 0-7785-2186-9 (Printed Edition) ISBN: 0-7785-2187-7 (On-line Edition) ISSN: 1496-7219 (Printed Edition) ISSN: 1496-7146 (On-line Edition) Pub No. 1/074 Illustration: Brian Huffman For copies of this report, contact: Information Centre - P ublications Alberta Environment Main Floor, Great West Life Building 9920 - 108 Street Edmonton, Alberta Canada T5K 2M4 Telephone: (780) 422-2079 OR Information Service Alberta Environment #100,3115- 12 Street NE Calgary, Alberta Canada T2E 7J2 Telephone: (403) 297-6674 This publication may be cited as: Scobie, D. 2002. 2001 burrowing owl trend block survey and monitoring. Brooks and Hanna areas. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report No. 51. Edmonton, AB. TABLE OF CONTENTS ABSTRACT ii ACKNOWLEDGEMENTS ii INTRODUCTION 1 STUDY AREAS 1 Kininvie 1 Hanna 3 METHODS 3 Kininvie Area 3 Hanna Area 3 Burrowing Owl Survey Protocol 2001 3 Productivity Monitoring 4 RESULTS 5 DISCUSSION . 5 MANANGEMENT IMPLICATIONS AND FUTURE DIRECTIONS 5 LITERATURE CITED 11 APPENDIX 13 LIST OF FIGURES Figure 1 . L ocation of trend blocks in Brooks and Hanna. Inset shows survey areas in respect to remaining percentage of native prairie (adapted from Shyry 1999) 2 Figure 2. Nests per 100 km2 6 Figure 3. Brooks K-block trend (linear regression) 8 Figure 4. Average number of j uvenile owls observed per successful nest site 10 LIST OF TABLES Table 1. Dates of trend block surveys 6 Table 2. Land surveyed in H-B locks in 2001 6 Table 3. Results of K-block burrowing owl 2001 trend block survey 7 Table 4. Number of nests observed during surveys 7 Table 5. Productivity results from K-Block burrowing owl nest sites/attempts found during the 2001 trend block surveys 9 Table 6. Average number of j uvenile owls observed per successful nest site 10 i Abstract Surveys were conducted in the Brooks (K-blocks) and Hanna (H-blocks) areas during June 18 - 27, 2001. Eight (8) burrowing owl nest sites and 2 s ingle owls were found in the K-blocks and no owls were found in the H-blocks. Productivity monitoring was undertaken in the K-Blocks between July 10 - 2 4 with 5.3 young per successful nest (n=6). Specific location details for all nests found have been removed from this document, as this report is for public distribution. Access was denied to 75 14 sections in H-blocks mainly because of concern of the upcoming federal Species At Risk Act. This is the second year that access has been denied on a p ortion of the Hanna Blocks and highlights the need for personal contact with all landholders in the K- block and H-blocks. Acknowledgements Appreciation is extended to trend block surveyors Christina Devlin, Jennifer Hemsing, Corey Scobie, and Rob Sissons (Avocet Environmental Inc.). Reg Russell (Alberta Sustainable Resource Development - F ish and Wildlife Division, Brooks) and Darcey Shyry participated in the trend block surveys and also assisted with the productivity monitoring. Arlen Todd (Alberta Sustainable Resource Development) and Reg Russell provided editorial assistance. The Alberta Species at Risk Program (Alberta Sustainable Resource Development) provided funding. A s pecial note of appreciation goes to the Eastern Irrigation District and all private landholders in Special Areas for allowing the continuation of surveys. Disclaimer The opinions and recommendations expressed are those of the author, and not necessarily those of Alberta Sustainable Resource Development. ii 2001 Burrowing Owl Trend Block Survey and Monitoring, Brooks and Hanna Areas INTRODUCTION The burrowing owl {Athene cunicularia) is a small bird of prey about the size of a R ichardson’s ground squirrel {Spermophilus richarsonii). Burrowing owls are unique in that they use the abandoned burrows of ground squirrels (S permophilus spp.), badgers {Taxidea taxus) and prairie dogs {Cynomys spp.) for nesting, roosting and caching food. The species is found in well-drained grasslands, prairies, steppes, deserts, and agricultural areas in the Americas from Canada to Argentina and Chile (Haug et al 1993). In Canada, burrowing owls were formerly found widely, but often sparsely, distributed across grassland regions of the prairie provinces, and in the interior of British Columbia (Wedgwood 1978). Canadian populations are migratory. Birds arrive in mid- April or early May and begin nesting shortly afterwards. They migrate southward to wintering areas in the southern United States or Mexico (James 1992, G. Holroyd, pers. comm.) in late September and early October. Burrowing owl populations declined dramatically over much of western North America over the last half of the 20th century. Wellicome (1997) discusses direct and indirect limiting factors attributed to human activities. These limiting factors (in no order of ranking) are habitat loss and degradation, mortality on migration or wintering grounds, pesticides, predation, collision with vehicles and shooting. The burrowing owl is ranked ‘G4’ in North America with widespread distribution, relatively common in appropriate habitat in some areas but habitat alteration and other factors are causing population declines in many areas (Nature Serve 2001). It is considered a ‘species of special concern' in most northern Great Plains states (Haug et al 1993, Martell 1991, Marti and Marks 1989). Burrowing owls are ‘endangered’ in Canada (a species facing imminent extirpation or extinction) by the Committee on the Status of Endangered Wildlife in Canada (2001) and designated as ‘threatened’ in Alberta (Alberta Sustainable Resource Development 2001). Avocet Environmental Inc. was successful in acquiring the bid contract “Burrowing Owl Survey - K a nd H B locks” in the County of Newell and Special Areas, Alberta, Canada. These surveys first started in 1991 and focus on locating burrowing owl sites within 269 permanent quarter section plots, following a standardized survey protocol. The H-Blocks were selected where owls once occupied whereas the K-B locks were randomly selected. Other species of national and/or provincial concern were recorded as incidental observations. Monitoring of these permanent trend blocks allows researchers to compare population trends using a standardized survey protocol (Shyry 1999). Shyry (1999) provides a d etailed description, rationale and summary of five years of these surveys from which many of the figures and tables presented in this report were derived. Avocet Environmental Inc. conducted the trend block survey for Alberta Sustainable Resource Development - Fish and Wildlife Division under the direction of Reg Russell, Alberta Sustainable Resource Development - F ish and Wildlife Division, Brooks, Alberta. STUDY AREAS KININVIE This study area is referred to as the K-Blocks (the terms Brooks and Kininvie are used interchangeably) (See Figure 1) and is comprised of 160-quarter sections in 10 regularly shaped 1 blocks located in the County of Newell, Alberta. The K-Blocks are situated approximately 35 km south and east of Brooks and are bounded by Highway 544 to the north and to the south by Highway 524. Habitat within the area is comprised primarily of native prairie interspersed with tame (i.e. crested wheat grass (.A gropyron cristatum )) r angeland. Figure 1 . Location of trend blocks in Brooks and Hanna. Inset shows survey areas in respect to remaining percentage of native prairie (adapted from Shyry 1999). HANNA The study area is referred to as the H-Blocks (See Figure 1) and is comprised of 109-quarter sections in 8 i rregularly shaped blocks located in Special Area # 2 . The H-B locks are found north of the village of Pollockville and extends to approximately 16 km east of Hanna. It is bounded to the east by East Berry Creek and to the west by Highway 36 except for block H3 that is located approximately 2 miles west of the village of Homestead Coulee. Habitat within the area is comprised of native and disturbed rangeland fragmented with annual crop cultivation. The H-Block and K-Block study areas lie within the dry mixed grass ecoregion of southeastern Alberta and the climate is characterized by hot, dry summers and cold winters (Strong 1992). The median annual precipitation in the region is 272 mm (Strong 1992). Native rangelands are dominated by Stipa-Bouteloua-Agropyron vegetation communities (Strong 1992, Coupland 1961). METHODS KININVIE AREA The 10 survey blocks in the County of Newell are comprised of 160 quarter sections. The dates of previous survey can be found in Table 1. Only 128 quarters were surveyed in 1993. The K- blocks are on land owned by the Eastern Irrigation District (EID). HANNA AREA The 8 survey blocks in the Special Areas are comprised of 109 quarter sections. The dates of previous survey can be found in Table 1. Only 76 quarters were surveyed in 2000. The H-blocks are on lands occupied by 21 individual landholders. BURROWING OWL SURVEY PROTOCOL 2001 Each quarter section (0.8 km by 0.8 km) had a G PS location for the center of the quarter. The K- Blocks were designed with 16 quarters per ‘block’ (3.2 km by 3.2 km) and the H-Blocks are irregularly shaped. A d ata sheet was used with 4 s ections per sheet (16 quarters) (See Appendix). Two observers were required per quarter. Elevated points were strategically chosen for best visibility roughly 1-200 m f rom the center. The all terrain vehicle (ATV) was shut down, waiting 5 minutes to let the effect of disturbance subside, while making a 3 60° pan of the quarter with aid of binoculars or spotting scope. The taped primary call was played for 5 minutes while scanning the area during the call. The caller was placed above the cargo box and the speaker rotated equally in each direction. Any nests/roosts or possible sightings were investigated before going on to the next quarter. Any ‘out of block’ burrowing owl sightings were also investigated and recorded. Surveys were not conducted on rainy days or days with wind speeds greater than approximately 20 km/hr., B-4 on the Beaufort Windscale. Surveys began at approximately 0600 and were usually completed by 1430. 3 When no young were seen, the minimum requirement for determining if a b urrow was a nest included: the presence of nest material (dung) in the burrow entrance, the presence of prey, pellets or prey parts, loose soil across the breadth of the burrow floor, feathers and whitewash. All pertinent owl evidence was recorded and an explanation given on the datasheet. If owls were detected after the 10-min. observation period, they were recorded with a clear note to explain where they were, how they were found and why they were missed. Adherence to the established protocol conducted by experienced observers ensures that bias is minimized between observers and different years. Navigation and georeferenced locations were recorded in the North American Datum 83 Universal Transverse Mercator format and achieved with Garmin™ 12 and 12XL Global Position System units. A p ermanent marker pin was placed 1 m away from the head of the burrow (area opposite the mound). To maximize the amount of information obtained, additional data was recorded on plots including landuse, human occupation, and % visibility. The following other species were also recorded on a presence/absence basis: ferruginous hawk, Swainson’s hawk, short-eared owl, Baird’s sparrow, upland sandpiper, loggerhead shrike, long-billed curlew and any other uncommon fauna. Burrowing owl feathers were also collected at nest sites as part of a stable isotope project being conducted at the University of Alberta. Two - 8 00 m Richardson’s ground squirrel transects were conducted per block recording used and all burrows either side of the ATV up to 1 m eter away resulting in 3200m2 surveyed. PRODUCTIVITY MONITORING Monitoring began one week after the first owlets were observed at a n umber of control nest sites within the EID. The protocol involved the observer positioning himself at a d istance so as not to influence the owls’ behaviour or at a d istance equal to the nearest existing above ground disturbance (e.g., road, wellsite, etc.) The observer then counted the total number of young observed, with the aid of binoculars or a spotting scope, during continual observation for a 3 0 minute monitoring period. Monitoring was undertaken during times of peak owl activity that occurs in early morning and early evening. Optimal monitoring times were 3 h ours beginning one-half hour before sunrise and a 3 h our period ending one-half hour after sunset. Monitoring was conducted with three visits on different days and the maximum number of owlets observed at a v isit was used to determine productivity at the nest. 4