Artificial Incubation of Sparrow Hawk Eggs

Abstract

Thirty-six fertile eggs of the sparrow hawk (Falco sparverius) were obtained from wild pairs and incubated in a small still-air incubator. The eggs were divided into six groups with three incubation temperatures (36.0, 38.S, and 40.0 C), and two treatments of cooling (30-minute cooling to 21.0 C twice daily and no cooling). From 19 eggs that hatched, 16 young sparrow hawks were reared to fledging. Of the 17 eggs that failed to hatch, 11 were either pipped or contained fully fonned embryos. An analysis of temperature treatments, on the basis of eggs hatched, showed 38.S C to be the best incubLation temperature (%2, P 0.05). Incubation temperatures from thermisterized eggs of captive sparrow hawks averaged 32.6 C. A thermisterized egg in the still-air incubator gave readings of 1.5 to 3.0 C below the indicated dry bulb temperature. The overall mean time from pipping to hatching was 55.4 hours. INCUBATION OF SPARRONV HAWK EGGS * Snelling 1299 cause a sizeable population of ospreys was present. Several theories may be expressed as to why a high rate of young (1.4) was produced per active nest. The Martin refuge, located 10 miles from the mainland, gets little disturbance except from the occasional commercial fisherman or private boater. The island refuge is also centrally located in Chesapeake Bay and may not be subject to the severe pesticidal and other chemical pollutants found concentrated in some tributaries that feed into the Bay. It has been shown that chlorinated hydrocarbons in the diet of raptors will cause eggshell thinning that ultimately results in reduced hatch success ( Hickey and Anderson 1968 ) . Both the lack of substantial human disturbance and a cleaner diet may contribute to the high nest success of the Martin refuge