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Ross' goose, showing the characteristic dusky patches on the head and shoulders of young of the year. From this 

 Characteristic, productivity for the year can be determined after the birds reach their wintering ground. (Photo by 

 John J. Lynch) 



indicate better than 38 percent production. In 

 1962, about 29 percent of the lesser snow geese 

 were immature, and 196:5 data indicate a produc- 

 tivity between 29 percent and 40 percent. Blue 

 geese innnalures constituted 32 percent of the 

 population in 1962, but preliminary data for 1963 

 indicate only 16 percent to 27 percent immature 

 birds in the population. 



Wood duck nesting structures. — Studies on 20 

 impoundments at the Patuxent Center revealed 



that predation of wood duck boxes by raccoons, 

 minks, and snakes was eliminated in 1963 by the 

 installation of aluminum predator guards 9 inches 

 wide and 38 inches long. These guards enclose 

 the post of the nest structure longitudinally in 

 "sandwich*' fashion. 



Tests of methods to discourage starlings from 

 using wood duck houses yielded valuable results. 

 In 1963, starlings used 37 percent of the conven- 

 tional vertical houses but only about 4 percent of 



18 



