Sumataiq 



Studies of selected migratory birds were conducted along the Yellowstone 

 River between Billings and Fairview, Montana, from September 1974 through 

 November 1976. Canada geese were most intensively studied, although observations 

 of ducks, bald eagles, and large fish-eating birds were also recorded. 



MAJOR BIRD STUDIES 



CANADA GEESE 



Canada geese were found to be present in the study area year-around. In 

 winter, geese were limited to areas of open water along the river, primarily 

 between Bighorn and Hathaway. A variety of crop types were utilized by field- 

 feeding geese in winter, although most were observed in corn and barley fields. 



During the spring migration periods as many as 16,000 geese were present in 

 the study area. Geese at this time loafed on open bars and islands on the river 

 and fed in a variety of crop types, corn and barley again appearing to be the 

 most heavily utilized. 



The goose breeding population, estimated at between 400 and 450 pairs, 

 initiated nests from mid- to late March, depending to some degree on the 

 weather preceding nest initiation. Goose nests were usually constructed on 

 islands on an open site, frequently near a driftwood log. Nest sites in the 

 more downstream study sections typically were more densely veqetated 

 than those in the more upstream study sections, apparently because ice covered 

 the open portions of downstream islands and bars during the nest initiation 

 period. Nesting densities ranged from 0.5 to 2.5 nests/hectare (0.2 to 1.0 

 nests/acre) on the most densely nested islands. 



Clutch sizes averaged just over five eggs/clutch. Goose nesting success 

 in 1975 and 1976 was 64 and 51 percent, respectively. Nest predation in some 

 study sections in 1976 was as high as 57 percent, attributed to greater predator 

 access to nesting islands in 1976 than in 1975 due to periods of low flow in 

 early spring. To prevent this degree of nest predation, 312 m-Vsec (11,000 cfs) 

 at Miles City may be needed during the spring. 



Based on egg sizes, 20 to 25 percent of the breeding geese in the areas 

 studied were giant Canada geese and the remainder Great Basin Canada geese 

 or hybrids of the two races. 



Goose brood-rearing areas were found to be diverse vegetatively. They 

 were usually close to the nesting islands and immediately adjacent to the river. 



The early fall resident population included resident breeders, their 

 current year's young, returning nonbreeders, and possibly some intermixed 



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