Artificial Incubation of Falcon Eggs

Abstract

The effectiveness of captive breeding as a conservation tactic for birds often depends heavily on successful artificial incubation of eggs. Incubation procedures for peregrine falcon (Falco peregrinus) eggs were developed using mathematical models and applying empirical information. Each egg was incubated as an individual at carefully regulated temperatures and under calculated conditions of humidity to maximize hatching success. Using this procedure, approximately 83% of all fertile peregrine eggs laid by captive falcons were hatched in 1979 and 1980. Over 90% of all fertile, live eggs received from wild peregrine falcon eyries between 1978 and 1980 were also hatched. The incubation procedures described for falcon eggs appear applicable for use with other bird eggs. J. WILDL. MANAGE. 47(1):158-168 In current peregrine falcon recovery efforts, successful artificial incubation and hatching of peregrine eggs is essential (Burnham et al. 1978, Fyfe 1975). In this paper I examine data that clarify questions regarding egg volume and weight, shell thickness, shell conductance, incubation time, and incubation and hatching procedures in artificial incubation of peregrine eggs. In addition, information obtained from peregrine eggs was used to develop procedures for artificial incubation of other bird eggs. I acknowledge The Peregrine Fund, Inc. (President, T. Cade) and all those who support the program without whose help this work could not have been accomplished. Special thanks are extended to D. Konkel and W. Heinrich for assistance in production of peregrine eggs and young, and to J. Enderson, J. Weaver, and G. Packard for advice and consultation. This manuscript was improved by the reviews of J. Enderson, S. Sherrod, R. Ryder, H. Enos, C. Carey, J. Grier, W. Graul, H. Rahn, L. Boyd, and T. Cade. The many drafts and final manuscript were typed by P. Burnham, whose patient and critical assistance is appreciated. METHODS The conditions under which captive peregrine falcons are held for breeding by The Peregrine Fund have been described previously (Cade et al. 1977). Falcon eggs obtained from captive pairs or nests in the wild (Burnham et al. 1978) were incubated in forced-air desk-top Marsh Farm Roll-X incubators which had been modified (Burnham 1978). All eggs were turned by hand bi-hourly. When eggs pipped they were moved to identical units with similar humidities but lower temperatures. Once the eggs hatched, the chicks were brooded by an Aquatic K-Module and K-pad orthopedic heat-pad (Hamilton Industries, Cincinnati, Ohio) that I adapted for the rearing of falcons. About 300 eggs produced by captive falcons at The Peregrine Fund facility in Fort Collins, Colorado, between 1978 and 1980 were used in this study. In addition, approximately 100 eggs were removed from peregrine eyries in Colorado and New Mexico and hatched in incubators; the resulting young were returned to the wild. Most clutches laid by wild peregrines were removed early in incubation 158 J. Wildl. Manage. 47(1):1983 This content downloaded from 157.55.39.171 on Sat, 25 Jun 2016 06:39:55 UTC All use subject to http://about.jstor.org/terms INCUBATION OF FALCON EGGS * Burnham 159 and transported to Fort Collins by automobile or aircraft in portable incubators operated at approximately 37.0 C. Initial (fresh) egg weights were seldom available and had to be estimated because an egg begins to lose weight after it is laid even though physical measurements of the shell remain the same. Consequently, I used Hoyt's (1979b) general equation for calculating the fresh weight of avian eggs (see Table 1):