BIRD COMMUNITY PARAMETERS 



Waterfowl Communities 



The relatively cool, moist spring and early summer of 1979 provided 

 favorable conditions for waterfowl; both waterfowl use and production 

 showed an increase over 1978. 



Breeding season species composition of all recorded waterfowl and 

 large water bird observations in the Mine Study Area is presented in table 

 10. Monthly changes in waterfowl species composition, as well as year- 

 to-year changes, are portrayed graphically in figure 17. The mallard 

 was again the predominant breeding waterfowl snecies; it constituted a 

 larger proportion of the total waterfowl community in 1979 than in 1978, 

 and increased in relative abundance over the breeding season. 



Waterfowl breeding season census data for stockponds in the study 

 areas are summarized in table 11. These data are converted to production 

 and density estimates in table 12; oroduction is shown graphically in 

 figure 18. Production (young/km^) showed a slight increase from 1978 to 

 1979 for all study areas. Breeding season waterfowl density in the originally 

 proposed mining area appears to be roughly twice that of the Mine Study 

 Area, while density in the Permit Area is slightly higher than that of the 

 Mine Study Area. 



The relationship among the number of broods, number of young, and 

 breeding pair censuses obtained by four different methods was examined 

 by means of Pearson product-moment correlation coefficients. The study 

 used 1978 and 1979 census data for all stockponds in the Mine Study Area 

 for which pairs and/or broods were recorded (a total of 67 censuses). 



All six census parameters were positively and significantly 

 (p<.01) correlated, indicating a close relationship between production 

 and stockpond use by pairs. Of the four breeding pair census techniques, 

 that described by Hammond (1969) and modified for this study (see WBS) 

 was the most strongly correlated with both the number of broods (r~'.84) 

 and the number of young (r'--.79). The results indicate that this method 

 is best for censusing breeding pairs. This analysis also shows that June 

 and July census data for young birds would be a single suitable parameter 

 for long-term monitoring of waterfowl production in the Mine Study Area. 



Waterfowl data obtained on the roadside surveys showed a trend very 

 similar to that mentioned above. As shown in figure 19, both the number 

 of species and number of observations of Anatidae and other water birds 

 (as recorded on June runs of the five routes) showed an increase over the 

 period 1977-1979. The sharpest increase occurred between 1977 (a very dry 

 year) and 1978 (a relatively moist year). A similar pattern is indicated 

 using pooled May-July data for the five routes. 



Data on broods observed during 1979 are presented in table 13. 



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