Moller, A. P. 1977. Yngletidspunkt , kuldstorrelse og ungerproduktion hos nogle 

 andefugle i Nordjylland. [Time of breeding, clutch size and nestling pro- 

 duction in some species of Anatidae in northern Jutland, Denmark.] Dan. 

 Ornithol. Foren. Tidsskr. 71: 68-69. [In Danish with English summary.] 



Owen, M. and W. A. Cook. 1977. Variation in body weight, wing length, and 



condition of Mallard Anas platyrhynchos and their relationship to environ- 

 mental changes. J. Zool. (Lond.) 183: 377-395. 



Pachenko, V. G. 1977. [A hybrid between the Mallard, Anas platyrhynchos , and 

 Teal, Anas crecca . ] Ornitologiya 13: 209-210. [In Russian.] 



Street, M. 1977. The food of Mallard ducklings in a wet gravel quarry, and 

 its relation to duckling survival. Wildfowl 28: 113-125. 



Vermeer, K. and C. D. Levings. 1977. Populations, biomass and food habits of 

 ducks on the Fraser Delta intertidal area, British Columbia. Wildfowl 28: 

 49-60. 



Williams, N. A., B. K. Calverley, and J. L. Mahrt. 1977. Blood parasites of 

 Mallard and Pintail Ducks from central Alberta and the MacKenzie Delta, 

 Northwest Territories. J. Wildl. Dis. 13: 226-229. 



Woolsen, L. 1977. A tree nesting Mallard. Loon 49: 183-184. 



1976 



Anderson, D. R. and K. P. Burnham. 1976. Population ecology of the Mallard: 

 VI: the effect of exploitation on survival. U.S. Fish & Wildl. Serv. 

 Resourc. Publ. No. 128. v and 66 pp. 



Balthazart, J. 1976. Daily variations of behavioural activities and of plasma 

 testosterone levels in the domestic duck Anas platyrhynchos . J. Zool. 

 (Lond.) 180: 155-173. 



Finley, M. T. , M. P. Dieter and L. N. Locke. 1976. Lead in tissues of Mallard 

 Ducks dosed with two types of lead shot. Bull. Environ. Contam. Toxicol. 

 16: 261-269. 



Heinz, G. H. 1976. Methylmercury : second year effects on Mallard reproduction 

 and duckling behaviour. J. Wildl. Manage. 40: 82-90. 



Johnsgard, P. A. and ■#.. DiSilvestro. 1976. Seventy-five years of changes in 



Mallard/Black Duck ratios in eastern North America. Am. Birds 30: 904-908. 



Miller, M. R. 1976. Cecal .fermentation in Mallards in relation to diet. Con- 

 dor 78: 107-111. 



Nilsson, L. 1976. Sex-ratios of Swedish Mallard during the non-breeding sea- 

 son. Wildfowl 27: 91-94. 



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