. Bulletin. Natural history; Natural history. Sept., 1970 Bellrose & Crompton: Migrational Behavior of Ducks A. \^^^A Fig. 4. —Axial lines, 1940-1945, of indirect band recoveries fron Chautauqua. nallards banded at Lake The latitude marked by the 47° and 48° parallels shows a peculiar variation in means.* In 13 of 17 years the axial lines show an abrupt swing east-south- eastward, from their points of origin in northeastern North Dakota into western Minnesota, but, then, in the next zone to the south (between the 46° and 47° * For all locations of areas designated by parallels and meridian
. Bulletin. Natural history; Natural history. Sept., 1970 Bellrose & Crompton: Migrational Behavior of Ducks A. \^^^A Fig. 4. —Axial lines, 1940-1945, of indirect band recoveries fron Chautauqua. nallards banded at Lake The latitude marked by the 47° and 48° parallels shows a peculiar variation in means.* In 13 of 17 years the axial lines show an abrupt swing east-south- eastward, from their points of origin in northeastern North Dakota into western Minnesota, but, then, in the next zone to the south (between the 46° and 47° * For all locations of areas designated by parallels and meridians, refer to frontispiece map. parallels) there is a swing back to the west, with all the mean points falling in southeastern North Dakota. This zigzag in the axial lines is apparently due to the limited distribution of mallard habi- tat in this zone. It should not be inferred from the zigzag in band recoveries that the mal- lards shift their passage similarly. Appar- ently Lake Chautauqua-bound mallards pass southeastward from Saskatchewan over eastern North Dakota and western. 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 Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
