Northern Saw-whet Owl (Aegolius acadicus) Chris Neri & Nova Mackentley
Whitefish Point, MI © Nova Mackentley (Click to view a comparison of Atlas I to II)
Thoughts of the Northern Saw-whet Owl often Distribution Significant movements of Saw-whet Owls have invoke memories of a winter day spent slowly been documented by Whitefish Point Bird walking through a pine stand, the frustration of Observatory in spring, summer, and fall. Peak investigating countless pinecones, and finally spring migration in the UP occurs from late your heart racing as a pair of yellow eyes stare March to late April, but movements can back at you from Michigan’s smallest owl. The continue through June (Mackentley and Neri Northern Saw-whet Owl breeds from Nova 2009 unpubl. report). Four years of summer Scotia to southern Alaska, extending south to research at Whitefish Point have resulted in the the mountains of southern California, Arizona, banding of 202 adult and 978 juvenile Saw- and New Mexico in the west, and into the whets in July and August (Neri and Mackentley southern Appalachians of Tennessee and North 2009, unpubl. report). The role of Michigan Carolina in the east. Barrows (1912) wrote breeders in these summer movements remains “doubtless more common than generally unclear, but these results have reduced the supposed”. By 1889 a Saw-whet nest had been validity of using juvenile Saw-whet sightings as discovered in Michigan (Brownell 1891), a means to confirm breeding. Juveniles banded another was described in 1893 (Morden 1893), at Whitefish Point in summer have been and ten nest records were known by the end of recovered as far away as coastal Virginia during the 1950’s (Zimmerman and Van Tyne 1959). the fall migration of the same calendar year While nocturnal surveys and banding efforts (Neri and Mackentley 2008b). Fall migration have shed some light on the occurrence of this peaks during the first half of October and species, a true understanding of its status continues into November (King and Bagnall continues to be elusive. The detection of 2007, unpubl. report). The winter status of this breeders is hindered by the species’ nocturnal species remains poorly understood, with most habits and relatively early breeding season. The reports being either chance observations or from fact that migration periods extend through the known winter roost sites. breeding season in Michigan further complicates efforts to determine breeding status. While reports during MBBA II were fairly
widespread throughout the state, Saw-whets became increasingly rare and localized to the
© 2011 Kalamazoo Nature Center Northern Saw-whet Owl (Aegolius acadicus) Chris Neri & Nova Mackentley south. As in MBBA I, most MBBA II reports previous breeding season by Pileated came from the UP where the number of possible Woodpecker (Parmelee and Johnson 1955), and breeders increased nearly five-fold, being Northern Flicker (pers. obs.). recorded in 8.21% of townships. While MBBA II results from the NLP were consistent with Males may begin their advertising calls as early those from MBBA I, the presence of four as late January and continue through May probable breeders in Oscoda County during (Palmer 1987). Clutch initiation has been MBBA II is noteworthy. With the exception of a observed in early March in Wisconsin cluster of reports from Lake, Mason, and (Bielefeldt and Rosenfield 1993) and in New Wexford Counties, Saw-whets were again York (Bent, 1938). In Michigan, eggs have poorly represented in the southern portion of the been reported on 12 May (Parmelee and NLP. In the SLP reports dropped from 11 Johnson 1955). Nests containing young have townships, including two probable and one been recorded on 30 April in Clinton County confirmed, in MBBA I to just five possible (Curtis 1963), 5 May in Isabella County township reports in MBBA II. (Morden 1893), and during the second week of June in Chippewa and Luce Counties (pers. Regional breeding bird atlas results are obs.). A family group was observed hunting consistent with those in Michigan. Atlasing together in Chippewa County from 3-9 August efforts in Ontario determined that the species (Crockett 1962). A nestling Saw-whet rescued breeds throughout the province. Organized from the Sleeper Lake fire in Luce County on nocturnal owl surveys found it reasonably well 23 August, 2007 (MiBCI 2007) demonstrates represented from Manitoulin Island to Sault Ste the potential for a second brood. The capture of Marie, but very localized in the western Bruce juvenile Saw-whets at identical stages of post- Peninsula to our east (Badzinski 2007). In juvenile molt between late July (pers. obs.) and Wisconsin it was most common in mixed forest mid-September (Bagnall and King, pers. uplands. Highest densities were reported in the comm.) at Whitefish Point also suggests the northeast, and only two reports came from the potential for late breeding, although it is southeast region of the state (Swengel 2006). To unclear whether or not the natal territories of the south, one confirmed report came from these birds were located within Michigan. northeast Ohio (Peterjohn and Rice 1991), and one probable report came from Indiana (Squires Abundance and Population Trends et al 1998). As is the case throughout most of the species range, data in Michigan is not sufficient for Breeding Biology confident population estimates. Estimates of the While the Northern Saw-whet Owl has been total North American population range from found nesting in a variety of wooded habitats 200,000-600,000 (Del Hoyo et al. 1999) to throughout its range, breeding densities appear 2,000,000 (PIF 2008), and it is considered stable highest in coniferous forests (Cannings 1993). enough to be considered a species of least These owls often prefer mixed woods with concern (Del Hoyo et al. 1999). conifers providing dense cover for roosting, and deciduous trees with nest cavities. In Michigan Organized nocturnal surveys in Ontario have they have been found nesting in habitats with documented fluctuations within the Saw-whet poplar sp. (Parmelee and Johnson 1955), breeding population from year to year. These quaking aspen (Peczynski 1991), ash, and jack fluctuations vary regionally, and are usually pine (pers. obs.). In Michigan nests have been synchronous with the rise and fall of local prey found in cavities that were occupied the populations (Badzinski 2009). The transition
© 2011 Kalamazoo Nature Center Northern Saw-whet Owl (Aegolius acadicus) Chris Neri & Nova Mackentley from the high to the low end of the breeding southeastern Wisconsin. Passenger Pigeon cycle can be a gradual or sudden change. From 55(2): 143-145 2007-2008, the population dropped 78% in Brownell, W.C. 1891. Some rare birds of central Ontario, and 40% in northern Ontario Wayne County, MI. Kansas City Scientist 5 (Allair and Badzinski 2009). (no.5): 78-80. Cannings, R. 1993. Northern Saw-whet Owl Conservation Needs (Aegolius acadicus). In The Birds of North Saw-whet Owl populations are likely stable in America, No. 367 (A Poole and F Gill, eds.). Michigan. However, management plans that The Birds of North America, Inc., provide nest trees with a diameter of at least Philadelphia, PA. 30.5 cm at breast height (Thomas 1979) would Curtis, R.D. 1963. Observations on the nesting be beneficial. The acceptance of artificial nest of the Saw-whet Owl at the Rose Lake boxes by this species provides an opportunity to Wildlife Research Center. Jack-Pine mitigate negative impact of logging in areas Warbler 41:3. where management plans do not meet these Crockett, D.B. 1962. Saw-whet Owls in criteria. Chippewa County, MI. Jack-Pine Warbler 40:3. Literature Cited Del Hoyo, J., A. Elliott, and J. Sargatal (eds). 1999. Handbook of the Birds of the World, Allair, J., and D.S. Badzinski. 2009. Nocturnal Vol. 5. Barn-owls to Hummingbirds. Lynx owl surveys in Ontario. Bird Studies Editions, Barcelona, Spain. Canada. Birdwatch Canada Magazine, King, W., and K. Bagnall. 2007. Fall 2007 owl winter 2009, number 46. research report. Whitefish Point Bird Badzinski, D.S. 2009. Nocturnal owl surveys Observatory unpublished report. coast to coast. Bird Studies Canada. Morden, J.A. 1893. Notes from Isabella County, Birdwatch Canada Magazine, winter 2009, MI. Oologist 10:24-26. number 46. Mackentley, N., and C.M. Neri, 2009. Whitefish Badzinski, D.S. 2007. Northern Saw-whet Point Bird Observatory’s Spring 2009 Owl Owl. In Cadman, M.D., D.A. Sutherland, Banding Research Report, Chippewa G.G. Beck, D. Lepage, and A.R. Couturier County, Paradise, MI. Whitefish Point Bird (eds). 2007. The Atlas of the Breeding Birds Observatory unpublished report. of Ontario, 2001-2005. Bird Studies Michigan Bird Conservation Initiative (MiBCI). Canada, Environment Canada, Ontario Field 2007. Owl hurt in Sleeper Lake Fire taken to Ornithologists, Ontario Ministry of Natural wildlife rehabilitator. Resources, and Ontario Nature. Toronto,
© 2011 Kalamazoo Nature Center Northern Saw-whet Owl (Aegolius acadicus) Chris Neri & Nova Mackentley Palmer, D.A. 1987. Annual, seasonal and Suggested Citation nightly variation in calling activity of boreal and northern saw-whet owls. US Forest Neri, C. and Mackentley, N. 2011. Northern Service General Technical Report RM: 162- Saw-whet Owl. (Aegolius acadicus). In 168. Chartier, A.T., J.J. Baldy, and J.M. Parmalee, D.F. and J.A. Johnson. 1955. Nesting Brenneman (eds.). 2010-2011. The Second of the Saw-whet Owl in Dickinson County, Michigan Breeding Bird Atlas. Kalamazoo MI. Jack-Pine Warbler 33:3. Nature Center. Kalamazoo, MI. Accessed Partners in Flight – U. S. (2008): PIF Landbird online at:
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