|Sponsor:||Weyerhaeuser Company Limited|
Object & Deliverables
The third Grande Prairie FMA Owl Monitoring Program occurred during the spring of 2013. This program had the following goals: 1) conduct nocturnal and diurnal owl surveys in Weyerhaeuser’s Grande Prairie FMA during the spring of 2013 using call playback surveys; 2) compare 2013 data with past surveys (2007, 2010); 3) compare the Grande Prairie results with results from the Alberta Nocturnal Owl Survey and previous surveys in Weyerhaeuser’s Edson and Drayton Valley FMAs; 4) document other raptors and wildlife observed during surveys.
Twenty nocturnal owl routes were surveyed twice. One hundred and twenty-six owls of six species were detected during this survey. Of these, 116 (92.1%) were considered non-duplicate owl detections. The most common owl detected was Northern Saw-whet Owl followed by Boreal Owl, Barred Owl, Great Horned Owl, Great Gray Owl, and Long-eared Owl. Relative abundance of Northern Saw-whet Owl, Boreal Owl, Barred Owl, Great Gray Owl, and Long-eared Owl were lower in the 2013 Grande Prairie FMA survey than in 2010 and 2007. The detection rate for Great Horned Owl in 2013 was higher than in 2007, but lower than 2010. Weather was mild during the nocturnal surveys. The following mean weather variable values were documented: wind was 1.78 on the Beaufort scale, temperature was -0.02OC, and cloud cover was 47.9%.
Thirty owls of five species were detected during the initial two-minute silent listening period of the nocturnal owl survey. The most common species detected during this period was Northern Saw-whet Owl, followed by Great Horned Owl, Boreal Owl, Barred Owl, and Long-eared Owl.
All twenty diurnal owl routes were sampled once. Six owls of four species were detected during this survey. All detections were considered non-duplicates using the ‘Alberta method’. Northern Pygmy Owl was the most commonly detected owl; Northern Hawk Owl, Great Horned Owl and Great Gray Owl were all detected once. Relative abundances of Northern Pygmy Owl and Northern Hawk Owl were lower in the Grande Prairie FMA during 2013 than 2007. Weather was mild during the diurnal surveys. The following mean weather variable values were documented: wind was 2.44 on the Beaufort scale, temperature was 5.75OC, and cloud cover was 61.3%.
Sixteen non-owl species were observed during the nocturnal owl survey including ten birds, five mammals and one amphibian. Thirty-five non-owl species were detected during the diurnal owl survey including 26 birds and 7 mammals. Twenty-six species (15 birds, and 11 mammals) were noted while traveling to survey routes and between survey stations.
Relative to the average detection rates obtained during the nocturnal surveys for Edson (2000, 2003, 2006, 2009), Drayton Valley (1999, 2005, 2008) and Pembina (2011), detection rates were lower in the Grande Prairie 2013 survey. The average detection rate for the 2013 nocturnal survey was also lower than the 2007 and 2010 Grande Prairie surveys. Diurnal owl detection rates found in the Grande Prairie FMA were lower than in Weyerhaeuser’s other FMAs. Compared to the Alberta Nocturnal Owl Survey, detection rates of the forest dwelling owls (Barred Owl, Boreal Owl, Great Gray, and Northern Saw-whet Owl) found in the Grande Prairie FMA were higher. Detection rates of Great Horned Owls and Long-eared Owls were lower in the Grande Prairie FMA than the Alberta Nocturnal Owl Survey. Lower rates in the Grande Prairie area are likely a function of preference that those species have for fragmented and open habitats. These habitats are more prevalent in the south where a higher proportion of these owls would be detected by the Alberta Nocturnal Owl Survey.
The Grande Prairie Owl Monitoring Program should continue in the long-term. Data that would be generated during a long-term program could be used to investigate whether owl populations are changing within the Grande Prairie FMA; between the Grande Prairie FMA and Weyerhaeuser’s other FMAs; and between the Grande Prairie FMA and the rest of the province by comparing Grande Prairie data with Alberta Nocturnal Owl Survey data.
 In 2011 the Drayton Valley and Edson FMAs were combined to form the Pembina FMA
The complete findings of this project are contained in the Final Report, called 2013 Grand Prairie FMA Owl Monitoring Program.