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--=======AVGMAIL-47456A832696======= Content-Type: multipart/alternative; boundary="=====================_175120796==.ALT"; x-avg-checked=avg-ok-734543F1 --=====================_175120796==.ALT Content-Type: text/plain; charset=us-ascii; format=flowed; x-avg-checked=avg-ok-734543F1 Hi NatureNS; The following message posted elsewhere should be of interest to NatureNS birders. We are certainly seeing shrikes this winter, and perhaps we'll be fortunate and snag a Great Gray Owl. . . ---------- Date: Wed, 21 Nov 2007 Subject: Boreal Birds - Ontario Updates Don Sutherland of the Ontario Ministry of Natural Resources (OMNR) tells me that the abundant meadow vole population last summer in the Hudson Bay Lowlands has almost certainly crashed. OMNR biologists did not see meadow voles in October and early November in areas where they were abundant in August. Newton (2006) states that microtine crashes often happen quickly following high populations. Owls: The high small mammal populations last summer in central and northern Ontario meant that most owls had an excellent breeding season with abundant prey to feed growing young. Note that most northern forest owls are rarely if ever affected by cold temperatures and deep snow unless they are starving. Small mammal populations (mainly voles) drive their breeding, abundance and movements. Northern Saw-whet Owl: A red-backed vole (preferred prey in Ontario) and deer mouse crash likely account for the very large flight this fall with hundreds recorded at banding stations. Boreal Owl: I'm not aware of any Boreal Owl sightings this fall in Ontario, but the heavy flight of Saw-whets and low vole numbers suggest some may come south. Boreal Owls can take larger prey than Saw-whets such as Northern Flying Squirrels. Two Boreal Owls have been banded so far this fall at L'Observatoire d'oiseaux de Tadoussac northeast of Quebec City on the north shore of the St. Lawrence River. The observatory is situated along the migratory route of the Boreal Owl. This cyclic owl often moves only short distances so it is best monitored by northern observatories. Great Gray Owl: One was seen on 19 November near Peterborough in central Ontario and another possible recent sighting in Muskoka. The crash of meadow voles (preferred prey in Ontario) in northern Ontario may cause more to show up farther south. However, Great Grays have the uncanny ability to find areas with high vole densities. They stop moving when they find abundant voles. Barred Owl: They are moving, with several reports along north shore of Lake Ontario, away from their normal habitats. This movement is likely linked to a crash of red-backed voles, deer mice and other small mammals in the Great Lakes - St. Lawrence Forest and southern Boreal Forest. Northern Shrike: The big southward movement this fall is probably resulted from the meadow vole crash in the boreal forest. Although Northern Shrikes eat small birds; they are mainly a vole specialist in winter. Birds are a buffer and form a greater proportion of Northern Shrike prey when voles are scarce. Boreal Chickadee: Indicators of a small movement include Bob Knudsen's report yesterday from Sault Ste. Marie to Ontbirds, a flock of 13 seen recently by Erwin Meissner near Massey west of Sudbury, and a report from Stephen O'Donnell of more sightings than usual near Sundridge north of Huntsville. A few may get as far south as Lake Ontario. Boreal Chickadees prefer thick conifers especially spruce. Listen for their husky calls among flocks of Black-cappeds, which had a significant southward movement this fall. Common and Hoary Redpolls - Subspecies: This year's big flight is providing an opportunity to study two subspecies of the Common Redpoll and perhaps two subspecies of Hoary Redpoll. Check link below to Tommy Thompson Park Bird Research Station in Toronto http://www.ttpbrs.ca/ This site has recent photos of two subspecies of the Common Redpoll (flammea and rostrata) and photos of a Hoary Redpoll (subspecies exilipes). They call the rostrata subspecies the "Greenland" subspecies of the Common Redpoll, but the common name used in most of the literature for rostrata is "Greater" Common Redpoll. The name Greenland Redpoll was normally restricted to the nominate subspecies hornemanni of the Hoary Redpoll. Sibley (2000) adds to the confusion by using Greenland for the northern subspecies of both Common and Hoary Redpolls. I suggest not using Greenland Redpoll because it is now used for the subspecies both species. In fact, both rostrata Common Redpoll and nominate hornemanni Hoary Redpoll have extensive breeding ranges in Canada so why even mention Greenland, which is misleading. The "Southern" Common Redpoll (flammea) is the commonest redpoll in southern Canada. It breeds as close as northern Ontario. The "Greater" Common Redpoll (rostrata) breeds on Baffin Island and Greenland. The "Greater" Common Redpoll is normally a winter visitor in small numbers. Rick Poulin (reported by Pittaway 1992)) banded hundreds of redpolls in the 1980s near Ottawa and found "Greater" Common Redpolls more common than Hoarys during some winters. The "Southern" Hoary Redpoll (exilipes) breeds in the low Arctic south to extreme northern Ontario. It is the usual Hoary seen in southern Canada in winter. "Hornemann's" Hoary Redpoll is the rarest redpoll in southern Canada. It breeds in high Arctic Canada and Greenland. Classic adult males are very large and overall much whiter with less streaking on the sides, and immaculate undertail coverts. Adult males have less pink with some having a mere trace of a pink suffusion on the breast. Not all redpolls will be identifiable to subspecies or even species, but most individuals can be distinguished with considerable confidence. Acknowledgements: I thank the following for keeping me informed: Ken Abraham (OMNR), Michel Gosselin (Canadian Museum of Nature), Jean Iron (Toronto), Erwin Meissner (Massey, Sudbury District), Marty Obbard (OMNR), Stephen O'Donnell (Sundridge, Parry Sound District), Don Sutherland (OMNR), Ron Tozer (Algonquin Park), Mike Turner (Haliburton Highlands) and Kirk Zufelt (Sault Ste. Marie, ON). Literature Cited and Websites: Newton, Ian. 2006. Advances in the study of irruptive migration. Ardea 94(3): 433-460. This is the most informative paper on irruptive species by a winter finch and raptor expert. Pittaway, R. 1992. Recognizable Forms: Redpolls. Ontario Birds 10(3): 108-114. Sibley, D.A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York. Tommy Thompson Park Bird Research Station, Toronto, Ontario. Website http://www.ttpbrs.ca/ Winter Finch Forecast 2007-2008. Archived at http://www.ofo.ca/reports%20and%20articles/winterfinches.php Ron Pittaway Minden & Toronto ON jeaniron@sympatico.ca ---------- ----------------------------------------------------------------------------- Blake Maybank maybank@ns.sympatico.ca Editor, "Nova Scotia Birds" author, "Birding Sites of Nova Scotia" http://maybank.tripod.com/BSNS.htm 144 Bayview Drive White's Lake, Nova Scotia, B3T 1Z1, Canada (902) 852-2077 --=====================_175120796==.ALT Content-Type: text/html; charset=us-ascii; x-avg-checked=avg-ok-734543F1 <html> <body> Hi NatureNS;<br><br> The following message p