Embryonic Heart Rate in Altricial Birds, the Pigeon (Columba domestica) and the Bank Swallow (Riparia riparia)

Abstract

Ballistocardiography or impedance cardiography was used to measure on a daily basis the heart rate (fH) of embryos of altricial pigeons (Columba domestica) and bank swallows (Riparia riparia). The patterns of fH changes during development were investigated. Embryonic fH of domestic and homing pigeons increases slowly during the middle stages of development and then increases sharply toward the end of incubation. Fantail pigeons show a diferent pattern of embryonic fH change; that is, fH remains constant until 1-2 d prior to external pipping and increases thereafter. Heart rate of the bank swallow increases continually throughout the last half of the incubation period. The developmental patterns of fH changes in pigeons and swallows generally are diferent from those of most precocial birds, in which embryonic fH decreases during the last stages of prepipping development.