Protection offered by nesting cover was evaluated by studying 529 simulated nests placed in nine vegetative covers. Of these nests, 278 were destroyed in the 10-day test period. Twenty-five percent of these simulated nests were destroyed the first 24-hour period, and 36 percent remained intact throughout the full test period. Grain fields, cat-tail ( Typha angustifolia), bulrush ( Scirpt4s ac?tus and S. validus)) and irrigation ditch vegetation provided more protection (30 percent destroyed), than tall weeds, willows ( Salix exigua and S. Iasiandra ), sagebrush ( Artemisia tridentata ), or downy chess ( Bromus tectorum) (80 percent destroyed). Alfalfa (Medicago sativa) provided a moderate amount of protection (40 percent destroyed). The black-billed magpie (Pica pica hudsonia) was found to be the most important nest predator on the Wilson Lake study area. A cover index that evaluated the visibility of eggs from all four sides and the top showed that heavier covers were more protective than light ones. WIAGPIE PREDATION * Jones and Hungerf ord 727 of the United States. The Ronald Press Company, New York. 769pp. PETERSON, J. E. (In press.) A method for the rapid, effieient extraetion and elean-up of biologieal samples for ehlorinated hydroearbon pestieide residue analysis. Bull. Environmental Contam. and Toxieol. ROSENE, W., JR., AND D. W. LAY. 1963. Disappearanee and visibility of quail remains. J. Wildl. Mgmt. 27 ( 1 ) :139-142. RUDD, R. L., AND R. E. GENELLY. 1956. Pesticides: their use and toxieity in relation to wildlife. California Fish and Game Dept. Game Bull. 7. 209pp. SHARP, H. F., JR. 1967. Food ecology of the rice rat, Oryzomys palustris (Harlan), in a Georgia salt marsh. J. Mamma1. 48 ( 4 ) 557463. SHELDON, M. G., R. B. FINT.F.Y, JR., M. H. MOHN, AND G. H. ISE. 1963. Aldrin eontamination of lakes at the Roeky Mountain Arsenal. Pages 63-64. In Pestieide-wildlife studies: a review of Fish and Wildlife Serviee investigations during 1961 and 1962. U. S. Bur. Sport Fisheries and Wildl. Cire. 167. lO9pp. SINGLETON-, J. R. 1953. Texas coastal waterfowl survey. Texas Game and Fish Comm. Ser. 11, P-R Rept., Project 29-R Segments l-5. 128pp. STICKEL, W. H., LUCILLE F. STICKEL, AND J. W. SPANN. 1969. Tissue residues of dieldrin in relation to mortality in birds and mammals. Pages 17W200. In M. W. Miller and G. G. Berg [Editors], Chemical fallout: current research on persistent pesticides. Charles C Thomas, Publisher, Springfield, Illinois. 531pp. TUCKER, R. K., AND D. G. CRABTREE. 1970. Handbook of toxicity of pesticides to wildlife. U. S. Bur. Sport Fisheries and Wildl. Resource Publ. 84. 131pp. U. S. BUREAU OF SPORT FISHERIES AND WILDLIFE. 1970. Wildlife research problems, programs, progress, 1968. Resource Publ. 85. 112pp. U. S. DEPARTMENT OF AGRICULTURE. 1966. Rice: annual market summary; 1966. Consumer and Marketing Serv. Grain Div.7 C & MS-18. 47pp. U. S. FISH AND WILDLIFE SERVICE. 1962. Effects of pesticides on fish and wildlife: a review of investigations during 1960. U. S. Bur. Sport Fisheries and \07ildl. Circ. 143. 52pp. ReceivecZ for publication January 4, 1971. For many years, the black-billed magpie and waterfowl ( Wetmore 1921, Williams has been blamed for reducing game populaand Marshall 1938, Greene 1948 ) . Efforts tions in the western United States. There to measure the influence of nest predation are many records of magpies destroying by magpies have arrived at widely divernests of pheasants (Phasianus colchicus) gent conclusions on the total effect of this 1 Present address: Delta Waterfowl Research P Station, Delta, Manitoba. Chesness et al. ( 1968 ) found that predaThis content downloaded from 157.55.39.93 on Wed, 27 Jul 2016 05:37:15 UTC All use subject to http://about.jstor.org/terms COVER PERCENT OF TYPES ACREAGE TOTAL AREA Sagebrush 125.0 1.5 Don7ny chess 6,585.0 80.8 Tall weeds 7.S 0.1 Willow 42.0 0.5 Bulrush 1.7 0.1 Cat-tail 4.8 0.1 Agricultural 1,385.0 17.0 728 Journal of Wildlife Management, Vol. 36, No. 3, July 1972 environmental factors that influence magpie predation on nests of pheasants and waterfowl. This report deals with nest cover and its protective value for game bird nesting.
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