Water loss from the eggs of a tropical sea bird ( Pterodroma phaeopygia) at high altitude

Abstract

1. 1. The water loss from the eggs of the dark-rumped petrel nesting at an altitude of 3000m in the Hawaiian Islands was studied. 2. 2. The conditions at the nest site were extremely dry and the calculated nest ventilation was very low (17.21/day). 3. 3. Comparisons with data from other Procellariiformes nesting at sea level suggested that the daily rate of water loss from the eggs of the dark-rumped petrel was high (134.5% of the predicted value for a procellariiform egg at sea level). 4. 4. The egg shells were thin and the shell mass was low—83.9% and 73.5%, respectively, of the values predicted for a procellariiform egg at sea level. 5. 5. It is believed that these features of the eggs are related to the altitude of the nesting site.