ARCTIC PEREGRINE FALCON Falco peregrinus tundrius (White) 



Order: FALCONIFORMES Family: FALCONIDAE 



Distinguishing characteristics : Like American peregrine falcon in general appearance, 

 but smaller and paler in coloration; black moustache marks on side of face narrower. 



Present distribution : Breeds in the treeless tundra area of Arctic Alaska, Canada, and 

 western Greenland. Migrates south chiefly through eastern and middle North America 

 to gulf coast of United States, middle and South America as far south as Argentina and 

 Chile . Band recoveries indicate that southward migration along the Atlantic coast may 

 be chiefly from breeding areas in western Greenland (Shor 1970) . 



Former distribution : Same . 



Status : Production of fledglings per occupied nest on Colville River, Alaska, dropped 

 from 1.40 in 152 to 0.5 in 1971; 53 percent of aeries unoccupied in 1970 and 1971. Mean 

 eggshell-thickness for this population decreased 21.7 percent since 1947; egg contents 

 average over 800 ppm DDE (lipid basis); and there is a highly significant negative 

 correlation between shell-thickness and DDE concentration in eggs (T.J. Cade and 

 co-workers) . In Ungava, of 8 aeries occupied in 1968, only one was occupied in 1969 

 (J. A. Keith); of 15 aeries examined in 1970, seven had a total of 12 young and 9 bad eggs 

 (D. D. Berger and co-workers) . Numbers have declined along the Thelon River in 

 Northwest Territories from 10 pairs in 1966 to 4 pairs in 1970 (R. Fyfe) . No obvious 

 decline in migrants along the Atlantic or gulf coasts nor consistent reduction in ratio 

 of young to adults has been shown (Ruos 1970); however, there has been a 31 percent 

 reduction in the western Great Lakes migrants from the 1938-40 average to the 5-year 

 period ending in 1967 (D . D . Berger) . Experience with the rapid decline of the American 

 peregrine indicates this subspecies is following the same pattern which led to collapse in 

 numbers . 



Estimated numbers: 200 to 300 pairs in Arctic Alaska (Cade); perhaps a few thousand 

 pairs in Arctic Canada (Fyfe), but assumption of a large population in Canadian Arctic 

 Islands may be erroneous (see J. Weaver and J. Grier in Cade and Fyfe, 1970). No 

 estimate for Greenland. 



Breeding rate in the wild : Average clutch size 3 (Cade I960) . Hatching success decreasing; 

 number of pairs failing to breed increasing. Dead young noted on nesting ledges in 1969 at 

 Bathurst Inlet and on Colville River . Periodic fluctuations in weather adverse to breeding 

 success must be taken into consideration along with other factors (Ruos 1970) . 



Reasons for decline : All field and laboratory evidence points to cumulative effects of 

 chlorinated pesticides and their breakdown products obtained from prey, especially DDT 

 and DDE, which have increased adult mortality and reduced production of young by 

 affecting reproductive mechanisms and causing eggs to become thin-shelled or otherwise 

 nonviable . 



Protective measures already taken : Peregrine falcons are protected at all times of the 

 year by Federal laws and the laws of most States and Provinces . Bureau of Sport Fisheries 

 and Wildlife, Canadian Wildlife Service, about 20 falconer-aviculturists, and Cornell 

 University are studying artificial propagation techniques with peregrines . 



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