populations were distributed among flyways in 

 roughly the same proportions. The most heavily 

 hunted species are: 





Average 



Apparent 







breeding 



population 



Trend 



Species 



population 



trend from 



since 





1955-1976 



mid-1950s 



then 





(Millions) 



to early 

 1970-s 





Mallard 



8.8 



Down 



Steady 



Green-wingec 



d 







teal 



7.2 



Down 



Up 



Greater and 









lesser scaup 



6.7 



Up 



Up 



Pintail 



6.2 



Down 



Up 



American 









wigeon 



3.1 



Down 



Down 



Northern 









shoveler 



1.9 



Down 



Steady 



Gadwall 



1.4 



Up 



Down 



Redhead 



.7 



Up 



Up 



Canvasback 



.6 



Up 



Steady 



The harvest of geese has not exhibited the radical 

 fluctuations that have characterized the duck harvest, 

 primarily because breeding habitat conditions in the 

 northern forested and Arctic tundra regions of Can- 

 ada and Alaska are more stable. The harvest of geese 

 has increased in the United States since the mid- 

 1950's and, in the first half of the 1970's, averaged 

 about 1,600,000 birds per year. Canada geese have 

 been most important, followed by snow and white- 

 fronted geese. 



Populations of the only swan species hunted in the 

 United States, the whistling swan, increased from 

 81,000 in 1967 to 157,000 in 1976. About 1,000 have 

 been harvested each year since 1971. Trumpeter 

 swans, which are found in western Montana, north- 

 eastern Idaho, Wyoming, Utah, Alaska, and Canada, 

 are estimated to number about 6,000. 



In every section of the country, more waterfowl are 

 harvested on private lands than on any other 

 ownership. Federal lands are most important in the 

 interior West, but they contribute only a fourth of the 

 total harvest in any section. State lands are most 

 important in the Northeast and on the Pacific Coast. 



Supply of Nongame Wildlife 



For the great majority of wildlife species that are of 

 particular interest to "nonconsuming" recreationists, 

 there is little empirical evidence of changes in popula- 

 tion levels. Trends have been evaluated systematically 



only for bird populations. Variations in the numbers 

 of birds in North America have been derived from 

 breeding population studies, autumn migration 

 counts, and winter population counts. 



Preliminary analyses indicate that most nongame 

 bird species associated with forest habitats have had 

 relatively stable populations during the past decade 

 when viewed on a continent-wide basis, although 

 there have been significant changes in the populations 

 of particular species (table 4.15). Most of these 

 changes appear to be related to changes in forest 

 stocking levels. A number of eastern species have suf- 

 fered significant population declines. Compensating 

 increases in populations of species typical of stocked 

 forest stands in the same areas is suggested by avail- 

 able data, but the evidence is not strong enough to 

 permit firm conclusions. ^^ 



Raptorial birds, often regarded as the most sensi- 

 tive indicators of environmental change, have been 

 monitored by autumn migration counts, or "hawk 

 watches," and by winter population counts, or 

 "Christmas bird counts." Raptor population trends 

 were examined for 12 species for the period 1967-74 

 to see whether changes could be correlated with 

 decreases in the use of organochlorine pesticides and 

 increased protection of the birds. The findings 

 include statistically significant decreases in the red- 

 shouldered hawk and increases in the sharp-shinned 

 and Cooper's hawk. Lesser decreases (not statistically 

 significant) were found in populations of the Harris 

 hawk, northern harrier, and the peregrine falcon, and 

 lesser increases were found in goshawk, kestrel, and 

 great horned owl populations. ^^ 



In a separate effort, average population levels of 17 

 raptorial species in the period 1948-1966 were com- 

 pared to average levels in 1967-74. Five species had 

 greater populations in the more recent period, five 

 had lower levels, and seven had no sigificant change. 



22 Capen, D, E., and S. P. Ahlefeld. Habitat associations and 

 population trends of nongame birds in forest ecosystems. School 

 of Natural Resources, Univ. Vermont, Burlington, Progress report 

 (mimeo). 1979. 



Cooper, R. J., and D. E. Capen. The 1979 RPA national assess- 

 ment of wildlife and fish: nongame birds. School of Natural Re- 

 sources, Univ. Vermont. Burlington. Final report (mimeo). 61 p. 

 1978. 



Robbins, C. S., and A. J. Erskine. Population trends in non- 

 game birds in North America. In Trans. No. Amer. Wildl. and Nat. 

 Res. Conf. 40:288-293. 1975. 



23 U.S. Department of the Interior, Fish and Wildlife Service 

 Environmental Assessment: proposed falconry regulations. Wash- 

 ington, D.C., 61 p. 1976. 



127 



