Long-Eared Owl (Asio Otus) Chris Neri and Nova Mackentley Status: State Threatened
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Long-eared Owl (Asio otus) Chris Neri and Nova Mackentley Status: State Threatened Whitefish Point Bird Observatory, (Click to view a comparison of Atlas I to II) Chippewa Co., MI 4/27/2008 © Joan Tisdale Cryptic coloration on a body stretched tall and Observatory (WPBO), Long-eared Owls occur spring through fall but are most common in thin, long ear tufts raised high, and a bewildered spring when as many as 80 have been observed stare from bright yellow eyes. Reluctant to leave during a single evening flight. the safety of its daytime roost, a Long-eared Owl will frequently exhibit this concealment Distribution posture when disturbed during daylight hours. Barrows (1912) described the Long-eared Owl However, in the comfort of the night its body as “by no means uncommon” in southern relaxes to stockier proportions, and the ear tufts Michigan during the late 19th and early 20th often are lowered as it begins the night’s hunt. centuries, but as practically unknown in the With the distinction of having the lightest wing NLP and reported just once from the UP. While loading of any North American owl, its flight is the distribution of recent reports from the LP are amazingly buoyant and effortless as it leaves its consistent with both Barrows’ 1912 assessment daytime roost. Chance upon Long-eared Owl and MBBA I results, the scarcity of reports from breeding grounds and you may witness the the SLP continues to be discouraging. During male’s zigzag courtship flight complete with the MBBA II Long-eared Owls were reported in sound of wing claps. The North American just 1.55% of SLP townships, with the only breeding range of this species spans central report of confirmed breeding coming from Canada from Nova Scotia to southeast Yukon Muskegon County. In the NLP they once again with populations extending south to Baja all but eluded detection, with confirmed California, southern Arizona, and southern New breeding only from Isabella County. However, Mexico in the west, and into the Appalachian atlas results from the UP continue to be Mountains of Virginia in the east (AOU 1983). relatively promising. Reports increased from The species is migratory through much of its 0.98% of townships in MBBA I to 1.45% in northern range, and birds banded in MBBA II. The confirmed report from Chippewa Saskatchewan, Montana, and Minnesota have Co is one of very few for the UP, and the first been recovered as far south as Mexico (Marks for the MBBA project. et.al 1994). In the SLP, where the species nears the southern limit of its breeding range, there In Ontario, nests have been documented in over may be year-round residency (Armstrong 1958, half of the counties and districts, but were Evers 1991). At Whitefish Point Bird © 2011 Kalamazoo Nature Center Long-eared Owl (Asio otus) Chris Neri and Nova Mackentley Status: State Threatened detected within the same atlas square just 6% of Michigan (Kenaga 1958). While possibly the time between atlas efforts. Due in part to this representing local breeders, recent summer low site fidelity and nomadic behavior, records at WPBO may indicate that post distribution in Ontario remains poorly breeding movements may occur by mid- understood (Konze 2007). In Wisconsin, where summer. Long-eared Owls have been recorded this owl had formerly been described as a very during each of the first four seasons (2006- common resident, it appears to be an 2009) of summer research at WPBO. These uncommon, yet widespread breeder (Shea records include three birds found day-roosting 2006). To our south, atlas efforts have on 21 July (pers. obs.), and six adult and four confirmed breeding just twice in Ohio and once hatch year birds banded 1-16 August (Neri and in Indiana, all occurring in northern counties Mackentley 2009, unpubl. report). While (Peterjohn and Rice 1991, Squires et al. 1998). limited, these records suggest that by mid July there are at least limited post breeding Breeding Biology movements within Michigan, and possibly into Occupying a wide variety of habitats throughout and out of the state by both adult and hatch year its range, in Michigan this species is most birds. frequently associated with coniferous or mixed coniferous habitats adjacent to large upland and Abundance and Population Trends wetland openings (Armstrong 1958, Getz 1961, While not federally listed, the Long-eared Owl Bosakowski et al. 1989a). The Long-eared Owl is listed as a species of special concern, or as is tolerant of conspecific nesters in close threatened in most mid-western, eastern, and proximity, sometimes forming loose colonies New England states in which it breeds (Marti with adults or family groups hunting the same and Marks 1989, Melvin et al. 1989, Petersen field (D. Holt, pers.com) and fledglings from 1991). Given Barrows’ depiction of early status multiple nests roosting together (Marks 1985, in the SLP, and the fact that seven breeding 1986). Of 507 Long-eared Owls banded on reports were confirmed from 1966-1970 (Kelley breeding grounds in Saskatchewan, only five 1966, 1970, Schroeder and DeBlaey 1968), the were recaptured in subsequent years, suggesting Long-eared Owl appears to be continually that breeding populations may be nomadic declining in southern Michigan. Historic reports (Houston 1997). Whereas nesting occurs almost from the NLP and the UP are too limited to exclusively in trees, a rare case of ground allow for any meaningful comparison. Whereas nesting has been documented in Michigan atlas results in the UP have been fairly (Jorae 1950). In Michigan, wintering individuals promising, breeding reports from the NLP typically disperse in March and early April, but continue to be extremely rare. With its winter roosts in southern Michigan have been nocturnal habits, relatively early breeding occupied by multiple birds as late as 25 April season, and cryptic coloration, this species is by (Reinoehl 2003). In North America, eggs have its nature particularly difficult to document as a been reported from 1 March to 5 June breeder. Overlap in migration and breeding (Johnsgard 2002), but 15 April to 5 May was seasons further complicate our ability to typical in Ontario (Peck and James 1983). On correctly document and confirm breeding. Much breeding grounds in Muskegon County, of our knowledge of the occurrence of this vocalizations were first heard on 13 March, species as a migrant has been gained through the courtship displays were observed on 26 March, long term owl research conducted by WPBO. and young were first observed on 4 June (C. The long term spring banding average is 43, Putnam pers. comm.), but young have been with maximum numbers of 173 (1995), 162 reported as early as the third week of May in (1999), and 138 (2009). Spring migration at © 2011 Kalamazoo Nature Center Long-eared Owl (Asio otus) Chris Neri and Nova Mackentley Status: State Threatened WPBO typically occurs from April through tolerance for the close proximity of conspecific May, peaking in mid-April to mid-May, but has nesters, the potential benefits of placing peaked as early as 27 March (Mackentley and multiple structures within a limited area are Neri 2009, unpubl. report). Fall records at greater for this species than for most other North WPBO have occurred from 8 September to 18 American owl species. November with peak migration occurring in October. The average number banded in fall (1993-2008) is four, with a maximum of 15 in Literature Cited 2006 (King and Bagnall 2008, unpubl. report). While reported fairly regularly in migration and American Ornithologists’ Union. 1983. Check- from known wintering sites, they are likely list of North American Birds, 6th ed. Am. significantly under-reported in all seasons. In Ornithologists’ Union, Washington, D.C. Minnesota, where winter reports averaged just Armstrong, W.H. 1958. Nesting and food four over a 30-year period, targeted surveys habits of the Long-eared Owl in Michigan. yielded 47 individuals in just two winter seasons Michigan State University Museum (Hertzel and Hertzel 2000). Increased Publications 1:61-96. monitoring targeted to detect this elusive species Barrows, W.B. 1912. Michigan Bird Life. East would likely result in increased reports. Lansing, Michigan Agricultural College However, a true understanding of the Long- Special Bulletin. eared Owl’s status as a breeder is likely to Bloom, P.H. 1994. The biology and current remain elusive for the foreseeable future. status of the Long-eared Owl in coastal southern California. The Bulletin of the Conservation Needs Southern California Academy of Sciences Although worldwide and North American 93: 1-12. populations are considered stable, this species Bosakowski, T., R. Kane, and D.G. Smith. has declined significantly as a breeder in many 1989a. Status and management of Long- states. Regional declines are typically attributed eared Owl in New Jersey. Records of New to habitat loss due to large scale agriculture and Jersey Birds 15: 42-46. extensive urbanization (Bosakowski et al. Bosakowski, T., R. Kane, and D.G. Smith. 1989b, Marti and Marks 1989, Bloom 1994). 1989b. Decline of the Long-eared Owl in The protection and management of open New Jersey. Wilson Bulletin. 101: 481-485. habitats for foraging and adjoining dense tree Evers, D.C. 1991. Long-eared Owl. In stands for roosting and nesting would be of Brewer, R., G.A. McPeek, and R.J. Adams obvious benefit. As a secondary nest user, Jr. (eds.). 1991. The Atlas of Breeding decreases in corvid and hawk populations have Birds of Michigan. Michigan State direct negative impact on the availability of University Press. East Lansing, MI. suitable nest structures. Studies in Britain have Garner, D. J. 1982. Nest-site provision documented the acceptance of manmade nesting experiment for Long-eared Owls.