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Brood Parasitism and Reproduction of Canvasbacks and Redheads on the Delta Marsh

出版	University of North Dakota, 1985
URL	http://books.google.com.hk/books?id=6B-mtwAACAAJ&hl=&source=gbs_api

註釋I studied brood parasitism and breeding ecology of canvasbacks (Aythya valisineria) and redheads (A. americana) nesting on the Delta Marsh near Portage la Prairie, Manitoba, from 1977 to 1980. The dissertation focuses on 3 aspects of this investigation: 1) the role of prairie drought in influencing pochard reproductive performance, including a comprehensive review of hypotheses explaining evolution of brood parasitism in waterfowl (Anatidae), 2) behavioral ecology and evolution of host/parasite interactions, and 3) development of improved redhead aging techniques by using cluster analysis. Redheads shifted egg distributions from eggs in redhead nests to eggs laid parasitically in canvasback nests during severe prairie-wide droughts. Furthermore, prairie droughts corresponded with: 1) apparently lower available food resources, 2) lower breeding season body weights, 3) lower attentiveness by incubating redheads, 4) greater spontaneous nest desertion, 5) higher emigration and nonbreeding.