English: Title: The Canadian field-naturalist Identifier: canadianfieldnat120otta (find matches) Year: 1919 (1910s) Authors: Ottawa Field-Naturalists' Club Subjects: Natural history; Sciences naturelles Publisher: Ottawa, Ottawa Field-Naturalists' Club Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book Click here to view book online to see this illustration in context in a browseable online version of this book. Text Appearing Before Image: 436 The Canadian Field-Naturalist Vol. 120 ing to the nest once, and twice the food transfer took place outside the nest. Prey delivery intervals at nest Number 1 varied from 49 minutes to 3 hours and 8 min- utes (on average 120.4 minutes ± 66.3 minutes, n = 8). These were longer than intervals between feeding of fledghngs reported by Lang et al. (1991) from north- em Manitoba: 48.5 min ± 34.9 SD (n = 12, range 10- 130 min). Of 10 observed prey items 7 were Meadow Voles (Microtus pennsylvanicus), 1 Northern Short- tailed Shrew (Blarina brevicauda), and the remaining two were either small mammals or small birds. The male removed heads of some voles before bringing them to the nest, whereas other prey was delivered whole. Prey beheading was also reported by Duncan and Duncan (1998). It was unclear whether the male ate the heads, as no cranial or dental material was found in pellets cast in the vicinity of the nest, although on one occasion, the female swallowed a prey item whole, head first. The female fed the young from beak to beak or held a partially skinned vole over the young's heads allowing them to tear at the carcass (Figure 5). In southern Cochrane District in 2001, Northern Hawk Owls nested in recent cutovers possibly treated with herbicides to stress regeneration of deciduous trees. These owls are known to utilize clearcuts for nesting (Duncan and Duncan 1998), and they showed preference for chemically treated clearcuts in north- western Ontario during their influx in the early 2000s (Escott 2002). Clearcuts with tall snags and few shrubs possibly mimic recently burned areas and other open habitats preferred by this species in its core range fur- ther north, and provide both nesting sites and open hunting habitat (Duncan and Duncan 1998). Popula- tions of some prey species (e.g.. Meadow Vole) may be more numerous in recent cutovers (Sullivan et al. 2004). Clear-cutting in northeastern Ontario will Uke- ly create more ephemeral nesting habitat for this species providing that groups of trees and snags remain after cutting. Acknowledgments I thank James R. Duncan (Manitoba Conservation, Winnipeg, Manitoba), Jack C. Eitniear (San Antonio, Texas), A. J. Erskine, and an anonymous reviewer for useful comments and suggestions regarding the man- uscript, George Peck (Royal Ontario Museum) for providing me with unpublished Northern Hawk Owl nest records, Audrey Heagy (Bird Studies Canada, Port Rowan, Ontario) for assisting in the review of the liter- ature and helping to obtain unpublished OBBA informa- tion, and Jay Malcolm (University of Toronto, Ontario) for information on small mammals and clearcuts. Text Appearing After Image: Figure 5. Pair of Northern Hawk Owls at nest. The male had just delivered a carcass of a Meadow Vole, and the female (on the left) is holding the vole over the youngs' heads allowing them to tear at the carcass (nest Number 1). Photo by Michael Patrikeev' 11 June 2005. Note About Images Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.