possible to increase productivity by "double- 

 clutching," which means taking the first clutch 

 to induce laying of a second. Removed eggs can 

 be artificially incubated or fostered to other wild 

 parents such as prairie falcons. Incubator-hatched 

 and captive reared peregrines may be held in cap- 

 tivity during the first critical year or two, then 

 released to the wild as adults. Artificial propaga- 

 tion and conditioning to survive in the wild could 

 be achieved by modification of falconry techni- 

 ques. Liberated falcons should be paired and psy- 

 chologically conditioned to accept suitable nesting 

 ledges or artificial structures in habitat where 

 food is adequate (Cade 1974). 



In 1970, the Laboratory of Ornithology and 

 Division of Biological Sciences at Cornell Univer- 

 sity began a propagation and restocking program 

 with $100,000 allocated by the University. At the 

 same time, Robert B. Berry began collaboration 

 with a breeding project in Pennsylvania. In 1973, 

 20 young peregrines were reared at Cornell, using 

 artificial insemination. Eggs were hatched in an 

 incubator. Multiple clutches were obtained by re- 

 moving eggs as laid. One pair produced 14 young 

 in 2 years. Two other pairs laid 3 clutches each, 

 totaling 24 eggs, and only 1 pair failed in fertiliza- 

 tion. Only birds taken from the wild as nestlings 

 breed easily in confinement. Reproductive cap- 

 ability is attained by captive birds at 3 years of 

 age (Cade 1973). In 1974, three mature pairs at 

 Cornell produced 21 young. A total of 23 young 

 from all pairs was reared that season. Two young 

 reared at Cornell were fostered to a pair of wild 

 Colorado peregrines that had lost their second 

 clutch through thin-shelled egg breakage due to 

 DDE. The fostered young fledged. Experiments 

 were begun on returning captive reared birds to 

 the wild by "hacking," which involved feeding 

 nestlings in two locations suitable for future 

 nesting sites until they fledged and flew away 

 (Cade ed 1974). From 1973 through 1975, 68 

 young from captive parents were raised. Eleven 

 pairs were laying eggs in 1975 at Cornell, and 

 that year a new breeding facility was started at 

 Fort Collins, Colorado, stocked with birds from 

 Cornell. At a facility in Alberta, the Canadian 

 Wildhfe Service raised 18 peregrines in 1975. 

 Others were reared by private breedings in Can- 

 ada and the United States (Cade ed 1975). Over 

 150 young were produced in captivity in all 

 facilities in 1977, half of which were from western 



North American anatum stock (Rocky Mountain/ 

 Southwestern Peregrine Falcon Recovery Team 

 1977). 



The first major restocking with captive-reared 

 birds was in 1975, when 16 were introduced to 

 the wild by hacking at 5 release sites. Two placed 

 on cliffs where peregrines formerly nested were 

 killed by great homed owls, showing need for 

 special protection against predators at natural 

 nesting sites. The remaining three sites were man- 

 made structures: one in a former gunnery tower 

 at Edgewood Arsenal on Chesapeake Bay in Mary- 

 land; another at Moose Hill Sanctuary of Mas- 

 sachusetts Audubon Society; and a third in a 

 specially built tower on an island near extensive 

 salt marshes in New Jersey. Other captive-bred 

 and raised individuals are being released in Canada 

 {Cdideed 1975 ; Cade and Dayne ed^ 1976). 



If reestablishment of a peregrine population 

 in the East is successful, it must be with stock 

 genetically different from the former typical ana- 

 tum of the Eastern Deciduous forest areas as none 

 of that population remains (King in press; Drury 

 in Clement ed 1974). The problem of artificial 

 rearing and restocking was reviewed at a National 

 Audubon Society sponsored conference in 1974 

 (Clement ed 1974). Choosing ecologically adapted 

 stock to replace the extince "rock peregrine" 

 population was debated. Stock from European 

 populations was suggested as possibly better 

 adapted to the eastern deciduous forest area than 

 other North American stocks (White and Cade in 

 Clement ed 1974). Stocks of various racial origins 

 were suggested as best to achieve greater genetic 

 diversity for natural selection to work with 

 (Hickey in Clement ed 1974). Special protection 

 of nesting peregrines from human disturbance at 

 traditional sties is considered particularly im- 

 portant in preservation and reestablishment of 

 populations (Hickey in Clement ed 1974). 



In summary, essential elements of a manage- 

 ment program are cooperation between govern- 

 ment and private agencies in the United States, 

 Canada, and Mexico in conducting population 

 surveys; rearing, fostering and introducing captive 

 reared birds to the wild; monitoring construction; 

 oil, gas, and mineral exploration; and recreational 

 activities that might interfere with peregrines, 

 with restrictions when necessary; and extending 

 and enforcing pesticide bans (Snow 1972; King in 

 press; Rocky Mountain/Southwest Recovery 

 Team 1977). 



